Today, we will consider a question inspired by Ray Asselin’s film “Old Growth Forests—Nature’s Biotic Water Pump”:

The Oregon coast, especially the South Coast in Northern California, seems perfect for the biotic pump action. It has a cool marine layer with lots of moisture and is heavily forested, with very little development except for the single hwy 101. Yet it has practically 0 summertime rain, on the coast and inland over the mountains. Any thoughts?

Why a Moist Coast Can Remain Dry

I understand the reader to be referring to the southern Oregon coast and the adjoining coast of Northern California. This region does indeed appear, at first sight, to be ideal for biotic pump action. A coastal forest belt of the order of 100 km in width borders the moist ocean on one side and a much drier continental interior on the other.

However, the forest does not act in isolation. Its influence is embedded in atmospheric circulation extending across the North Pacific and the North American continent. The biotic pump effect of the forest can become pronounced when these larger-scale conditions allow or reinforce rising air motion. When the larger-scale circulation causes the air to descend, the forest remains largely at its mercy.

The conventional explanation for the almost rainless summers begins with the North Pacific High. In summer, this enormous region of high atmospheric pressure strengthens and moves northward, while the Pacific storms that bring winter rain retreat toward higher latitudes. Oregon and Northern California are situated on the eastern side of the High, where the air generally descends.

Descending air is compressed and becomes warmer. Close to the surface, meanwhile, the marine air remains cool because the coastal ocean is cold. This produces a temperature inversion: warm air lies above the cool, moist marine layer and acts as a lid. The marine layer can contain abundant moisture, fog and low clouds, but it cannot rise high enough to produce substantial rain.

The clockwise circulation around the North Pacific High also generates the persistent northerly winds along the coast. These winds push surface ocean water away from the coast, allowing colder water to rise from below. This coastal upwelling cools both the ocean surface and the air above it, strengthening the temperature inversion still further.

The following two images from Earth Nullschool illustrate the difference between the local surface circulation and the much larger circulation above it. They are individual snapshots rather than long-term climatic averages, but they make the difference in scale visible.

The green circle marks the coastal region referred to in the question. In the animated Earth Nullschool map, the surface air is moving predominantly from north to south, approximately parallel to the coastline. It is not carrying oceanic moisture directly inland across the forest belt. The brighter green colors offshore indicate stronger winds, while winds over the continent and in some coastal areas are much weaker.

This is the characteristic summer coastal current associated with the eastern side of the North Pacific High. It favors coastal upwelling and a cool marine layer, but not the convergence and rising air required for rainfall.

Surface winds along the west coast of North America. The green circle marks the southern Oregon and Northern California coastal region. Source: Earth Nullschool, accessed 25 August 2026.

The second image shows the winds at a pressure level of 500 hPa, corresponding to an altitude of approximately five to six kilometers. At this height, the atmospheric flow is much broader and stronger. It is organized on the scale of the entire eastern Pacific and western North America. The coastal forest belt, which was readily visible as a geographical feature in the surface map, is now only a very small part of a circulation system thousands of kilometers across.

The maps display horizontal winds and do not show descending motion directly. To see the descent itself, we would need to examine vertical air velocity. Nevertheless, the two images illustrate the basic problem: the surface processes generated by the coastal forest are embedded within, and constrained by, a much larger three-dimensional atmospheric circulation.

Winds at 500 hPa, approximately five to six kilometers above sea level. The broad atmospheric flow extends across the Pacific coast and the continental interior. Source: Earth Nullschool, assessed 25 August 2026.

What Creates the North Pacific High?

Thus, the conventional explanation tells us why abundant moisture near the coast does not automatically produce rain. The air must rise and cool for its water vapor to condense and fall as precipitation. Forest transpiration can add moisture and help air rise locally, but it generally cannot overcome the persistent descent and strong atmospheric stability associated with the North Pacific High.

However, this explanation tells us more about how the High suppresses rainfall once it is present than about why the High forms where it does and why it becomes so strong. The physical causes of the Northern Hemisphere subtropical anticyclones are not entirely settled.

As Seager et al. (2003) wrote:

The mechanisms that underlie the development and maintenance of the subtropical anticyclones are still in dispute.

In their model, heating associated with the summer monsoons over land produced subtropical anticyclones, but they were weaker than those observed in the real atmosphere. Additional amplification was needed. Seager and colleagues proposed that this amplification was provided by interactions between the ocean and atmosphere. In simple terms, the initially weak circulation changed ocean temperatures and the distribution of rainfall, and those changes then strengthened the circulation.

Miyasaka and Nakamura (2005) obtained a substantially different result. They emphasized a relatively shallow heating and cooling pattern near the surface. In their words, their numerical experiments showed that:

those highs can be reproduced in response to a local shallow cooling–heating couplet associated with this thermal contrast.

On one side of this couplet lies the cool eastern Pacific, where the cold ocean and extensive low clouds cool the lower atmosphere. On the other side lies the hot and dry North American landmass, where much of the absorbed solar energy directly heats the land surface and the air above it. Meteorologists call this direct transfer of heat from the surface to the air “sensible heat.”

The zonally asymmetric component of near-surface air temperature in May, illustrating the temperature contrast between the cool eastern Pacific and the warmer North American continent. Source: Miyasaka and Nakamura (2005), Fig. 13a.

Their Fig. 13a reproduced above illustrates the pronounced temperature contrast between the cool eastern Pacific and the warmer continent, already present in May. The causal evidence comes from the numerical experiments that follow, including the model response shown in their Fig. 14c. When the model was driven only by heating from deep convection higher in the atmosphere, the resulting anticyclone was weak. The authors therefore proposed that the North Pacific High and the hot continental low to its east form part of a local, mutually reinforcing system.

Could Continental Dryness Strengthen the High?

From this point onward, I would like to mark the following argument clearly as our own speculation.

Neither Seager et al. nor Miyasaka and Nakamura asked what the North Pacific High would be like if the western North American interior were densely vegetated. However, the results of Miyasaka and Nakamura suggest a possible answer.

Vegetation uses solar energy to evaporate water. A densely vegetated, well-watered land surface therefore remains cooler than a dry surface, where most of the same solar energy is used to heat the ground and the air. If the continental interior were more densely vegetated, more energy would be used for transpiration, less would appear as sensible heat, and the temperature contrast between the continent and the eastern Pacific would be smaller.

If this land–ocean heating contrast contributes substantially to the North Pacific High, as the experiments of Miyasaka and Nakamura indicate, a cooler and more densely vegetated continental interior could result in a less intense High. Conversely, the present dryness and sparse vegetation of much of the interior may contribute to maintaining the strong anticyclone that prevents the Oregon coastal forests from fully realizing their biotic pump potential.

Continental dryness may therefore be not only a result of the atmospheric circulation, but also part of a feedback that reinforces it.

When the Land–Ocean Temperature Contrast Becomes Too Large

There is another reason why a large temperature contrast between the ocean and land can interfere with biotic pump circulation. We discussed this mechanism in our paper, “Vegetation impact on atmospheric moisture transport under increasing land-ocean temperature contrasts”.

The basic idea of the biotic pump is that condensation removes water vapor from the atmosphere. This reduces air pressure and helps draw more moist air toward the region where condensation is occurring.

Now consider moist air moving from a cool ocean toward warmer land. As it travels over increasingly warm surfaces, more water evaporates into it. The air eventually rises, cools, and loses some of its water vapor through condensation. How much vapor condenses depends partly on how high the air rises before turning and flowing away.

The water vapor added through evaporation during the horizontal journey partly replaces the vapor removed by condensation during the ascent. As we wrote:

Addition of water vapor by evaporation in the horizontal flow partially compensates for the pressure drop by condensation in the ascending air.

If the land is only moderately warmer than the ocean, condensation can still produce the pressure decrease needed to maintain moisture inflow. But when the land–ocean temperature contrast reaches a critical value, evaporation adds as much water vapor as condensation removes. The pressure decrease then disappears, and condensation can no longer sustain the inflow.

The limiting temperature contrast depends on how high the air rises and, consequently, on how much of its water vapor has condensed before the air begins its return journey.

In several Eurasian regions that we examined, the observed land–ocean temperature contrasts were already close to this theoretical limit. We have not performed the corresponding calculation for Oregon and western North America, so applying this mechanism to the Oregon coast remains a hypothesis. Nevertheless, it provides another physical reason why an excessively warm and dry continental interior could inhibit ocean-to-land moisture transport rather than strengthen it.

The original question may therefore need to be reformulated. It does rain in this region, and it rains enough for the forest to exist. However, most of the rain falls during the cooler part of the year, when the North Pacific High retreats and Pacific storms can reach the coast. Fog supplies some additional water during summer, but fog is not equivalent to rain and cannot fully replace it.

A forest does not have to produce the same amount of rainfall in every season. It can reinforce moisture transport when the larger-scale circulation provides an opportunity for air to rise and water vapor to condense. There is little point in expecting a relatively narrow coastal forest belt to overcome, on its own, an adverse circulation extending across the North Pacific and the North American continent.

We should therefore study when it does rain in this region, how the forests facilitate rainfall under those conditions, and how the condition of the continental interior affects the larger-scale circulation.

Our speculation is that greening the continental interior would not benefit only the interior itself. By reducing sensible heating and the land–ocean temperature contrast, it could weaken the conditions that suppress summer moisture convergence and help the Oregon coastal forests realize more of their biotic pump potential.

Related Question from Pennsylvania

The possibility that greening the continental interior could alter the larger-scale circulation constraining the Oregon forests leads naturally to the following question from a regenerative farmer and researcher in Pennsylvania:

Hello, Biotic Pump Greening Group,

Could you describe the physics of how the low surface pressure created by hyper-transpiring vegetation could potentially draw moist air from the Gulf of Mexico, rather than allowing it to be replaced by the dry prevailing westerlies descending from the Rocky Mountains? I am using North America as an example.

I am thinking of a scenario in which all of North America’s soils and ecosystems were managed regeneratively so as to retain 90 percent of rainfall. The land would support deep-rooted, mostly perennial vegetation, with excellent nutrient cycling and management, resulting in very thick, healthy vegetation. Its evapotranspiration potential could be up to twice that of an equivalent area of ocean. In other words, it could return rainwater to the atmosphere very quickly.

In this context, would the biotic pump allow moisture and vegetation to advance northwestward into desert regions despite the dry air descending from the Rocky Mountains? Or would hyper-transpiring vegetation on the windward side of the western U.S. mountain ranges be the only way to bring more moisture over the mountains and into this dry interior?

This question is closely related to the North American questions discussed in Biotic Pump Q&A #3: Bringing Water to Drier Landscapes. There we considered how much moisture remains after Pacific air crosses the Rocky Mountains, how vegetation east of the mountains could replenish that moisture and trigger convection, and how this could attract additional low-level moisture from the Gulf of Mexico. Rather than repeat that discussion here, I will add one further consideration arising from the Oregon example.

As discussed above, the hot and dry continental interior may contribute to the intensity of the North Pacific High. If the proposed large-scale revegetation cooled the land through increased transpiration and thereby weakened the High, the large-scale descending motion associated with the High over the western mountains would also be reduced. This would make it easier for moist air to rise over the mountains and penetrate into the dry continental interior.

Thus, continental revegetation could help not only by returning water to the atmosphere and recycling rainfall, but also by weakening one of the larger-scale circulation patterns that currently obstruct moisture transport. In this additional sense, the proposed revegetation would help the biotic pump extend moisture and vegetation into the drier regions of North America.

Related reading:

Nature as Healer

Humans are social beings, and encouragement or simply interest from peers is an essential ingredient of any successful human activity, including, and especially, intellectual endeavours. So when Victor Gorshkov, the founder of the biotic regulation and biotic pump concepts, abruptly changed the direction of his research career, moving from theoretical physics to the foundations of life’s stability, he just as suddenly found himself in complete scientific loneliness. His former colleagues were not quite interested in what he was doing, while biologists did not quite appreciate the theoretical physics approach he was bringing in. Alienated by all, he faced a difficult time.

Yes, as I previously wrote, truth itself and its discovery can be great sources of inspiration and positivity. Yet the situation was aggravated by the fact that he also had to publish, meaning that he was dependent on those very people who had alienated him to approve his work for publication and give it the peer-reviewed label. Nate Hagens recently reflected in one of his Franklys on a related form of loneliness: the loneliness of seeing the world differently from most people around him. Fortunately, Nate can speak directly to his audience through a platform of his own. Victor worked in the pre-Internet era and depended on others to publish his work.

That is to say, biotic regulation began in a peculiar atmosphere of exciting discoveries and social isolation. To cope with the downside, Victor found a way: he travelled to the wilderness areas of the Soviet Union and, later, Russia: to the Urals and to the Ob and Yenisey rivers. Siberia is magnificent.

Later, he began to travel to the White Sea, which is in the European part of Russia, 700 km north of St. Petersburg. Eventually, I joined Victor there, and this region became my wilderness motherland. Today I want to describe a particular practice that I invented, one which helped me come to terms with myself and the world and return from the White Sea pilgrimage ready and eager for another year of fighting.

The White Sea Seals

Although the White Sea is relatively close to industrial centres, its southern region remains largely wild because of its high tides, with the water level rising and falling by about a metre and a half. The seabed is quite flat, which means that twice a day very large coastal areas become inundated and then dry again. Since people normally travel in small boats on this inner sea, and since the winds are strong and unpredictable, all this makes it difficult to develop and deforest the coastal area, which therefore remains quite wild. This was especially true in the 1990s, when economic activity was low. It was then that animal life began to flourish. Later on, with the development of tourism, it declined again.

But in springtime, when we travelled by kayak, first down a small river to the sea and then from one small island to another, the sea remained pretty uninhabited by humans, allowing wildlife to follow its course undisturbed.

So our story will be about the seals. Several species of seal inhabit the sea. Local people do not normally hunt seals, so they are only moderately cautious when they climb onto the rocks to relax and take air baths. As the tide recedes, they can remain on the rocks for hours, and during this time it is theoretically possible to come close to them, moving slowly between the rocks.

This was the type of “hunt” I invented: moving very slowly between the rocks and the small pools left behind, trying to come very close to a seal, as close as possible, and spend as much time as possible near it.

Usually, these moments do not last very long, because the seal periodically looks around, and when you are very close, no matter how immobile you are, and even if you choose to approach the seal from the direction of the sun, it still notices you all of a sudden and then escapes into the water. But you can take some good photos at such close range.

This photo, which I called Sea Beauty, was taken in this way. After about three hours of slowly approaching the animal, I made a final leap to the very stone where it was lying. She looked up and saw me within arm’s reach, and before she disappeared into the crystal-clear seawater, I was fortunate enough to take this shot. I am no professional photographer, and my cameras are quite basic, but I still consider it to be a fairly good shot because I managed to come very close.

Sometimes young seals do not quite understand this trick of the sea disappearing and leaving them hundreds of metres from the waterline. In this vulnerable situation, they can become easy victims of bears and even foxes. When this happened, we would take them back to the water.

Besides the smaller species of seal, there are also larger seals known in Russian as “sea hares.” They are really big, can be more than two metres long, and are found far from the coast, usually on small islands or rocks. Because they are so large, they are not afraid of other animals in the way smaller seals are, although they immediately escape when humans approach them in a boat.

One day I was able to achieve something truly remarkable. I saw one such seal taking a nap on a rock and decided to approach him from the waterline. He was facing away from the waterline, looking towards the shore, while I moved slowly towards him. Whenever he looked in my direction, I would stretch out flat on the rock, pretending that I was just another seal relaxing nearby. Of course, I did not look exactly like a seal, but, on the other hand, he might have thought: Mother Nature is full of wonders, so why not?

In this manner, I was able to approach this seal very, very closely, and I lay parallel to him about a metre away. He was mostly sleeping. I could have touched him, but after some hesitation, I decided that it would be disrespectful.

When he awoke and saw me so close, I could see that a difficult calculation was going on in his brain. On the one hand, I looked bizarre and was not very small, so I was potentially dangerous. On the other hand, he realized that I’d been around for quite some time, and he hadn’t escaped, so it would not be quite comme il faut to suddenly rush away. Why should he, after all, when he could simply wait for this bizarre creature to move away instead?

During this calculation, I took a selfie with him, and then he chose to splash into the water. It is not an ideal selfie, I agree. But take into account that I was standing in the water on a small ridge of a sloping cliff, trying to pretend that I was a seal, keeping my camera from sliding into the water, and all that. Given such conditions, this selfie is quite good; it is dear to me.

Being close to a wild animal that is not alarmed by your presence and watching how this animal’s life unfolds and how it contemplates the world make for a very special feeling. It feels like you have found an invisible spring of vitality and can drink from it in peace. It is as if you have been admitted to this world of vitality and resilience that exists as long as we don’t violate its rules.

Foxes

Another acute feeling of this sort came when we had a fox visitor. I know foxes are quite common in many suburban environments, so many people would not even be impressed by a fox as part of the wildlife. But that was a perfectly wild fox in the sense that she had been born on a large, distant island and had never seen humans, only bears and moose. Therefore, when she came to the lawn where our tent was standing and saw some big animals around, she did not hesitate to look for something to her taste. She behaved as if we were bears, and this was very funny.

We thought that she would come the next day, and so we prepared. We put some cheese on a piece of log standing upright. And when she came and smelled the cheese, she stood up and ate it while we watched and remembered the famous fable of the crow and her cheese, which was stolen by the fox. Again, it was this beautiful feeling of being present in a world of natural vitality spread all around you and available for you to draw strength from.

Then, on May 10, 2019, Victor died. It was the moment when I had to summon all my strength to overcome this loss and survive. It was a beautiful May, and then came a beautiful, green June. To cope with grief, I would wake up early in the morning at around five or six and walk many kilometres through the forest near our dacha. Once, at grey dawn, I saw some small movement on an abandoned road in the distance. At first, I thought I was seeing young birds being led by their mother, but then I realized that they were very small fox cubs. I also saw their mother a little farther away, extremely worried.

Looking at her face and hearing her cry, I saw how terrified she was that I might harm her babies. Her pain resonated with my own, and I walked away.

A few days later, I returned along the same road. This time it was a bright, sunny morning, and suddenly I saw the cubs playing around what turned out to be their home, a burrow beneath the road. They had grown noticeably. I realized that the mother was not around, and I began to approach them slowly. Apparently, they had never seen humans either. Without their mother there to warn them, they allowed me to come very close. I spent about two hours sitting with them and watching them play, sleep, and explore the world. Birds were singing around us. Dandelions were about to spread their seeds but were still untouched in their fragile beauty. It was as if Victor was talking to me through the language of this beauty.

I returned once more a few days later, and the small foxes were still there, having grown a little more, and I made some good video clips.

Later in that beautiful summer, I watched bees visit a beautiful three-dimensional flower trembling near the river. And I saw birds eating seeds from another flower, while a distant train signalled where the border between nature and civilization lay. Nature was talking to me.

It was not that the wound was healing rapidly, but it stopped being an erupting volcano of grief. For me, a new life was hatching, and I was again fully present, ready to carry biotic regulation and the biotic pump forward, towards the dawn of a new civilization. Without those foxes, birds and flowers, I would not be here now.

Announcement

I’ve spoken many times about the science of biotic regulation and the biotic pump, but much less about this important dimension behind the science: our experiences in nature and how they matter. I have seldom been asked about that. So I was exceptionally pleased to be invited to participate in the Re-Rooting Ourselves in Nature online speaker series organized by Earth Activist Training. You can find the relevant information below.

I feel very privileged to take part in a series that also includes Judith Schwartz (Stories of Hope), Dr. Lyla June (Indigenous Regenerative Food Systems, Past and Present), Scott Richardson-Read (Ancestors of the Land), Paulinho Muzaliwa (Re-Rooting as a Refugee), Nadia Lawton (Greening the Desert), Bonita Eloise Ford (Water & Fireflies: Grieving & Thriving for Community Activists), and Jonathan Belarmino (Re-Rooting in the Brazilian Atlantic Rainforest).

Description of my session on October 6:

The Planet’s Moisture Pump: Dr. Anastassia Makarieva, along with V. G. Gorshkov, formulated the concept of the biotic pump: the atmospheric transport of moisture from ocean to land, a process that sustains terrestrial life. Drawing on more than five years of forest research in the Russian wilderness, Anastassia will help us understand this ecological system and the wider importance of forests for water and climate. She will also share how she thrives in one of the most remote places on the planet and reflect on what wilderness can teach us about our search for meaning.

Earth Activist Training is excited to host Re-Rooting Ourselves in Nature, a series of conversations with wisdom keepers, educators, scientists, authors, and activists from around the world about modern applications of deep-time practices. This weekly online speaker series will consist of live 90-minute sessions on Tuesdays from September 22 to November 10, 2026, at 9 a.m. Pacific Time. Each session will be recorded and closed-captioned. Sliding-scale registration is available for individual sessions or for the entire series.

Learn more about the series and register: https://earthactivisttraining.org/re-rooting-ourselves-in-nature/

I look forward to seeing you there if you are interested.

Subscribe now

Nate Hagens, in a recent episode of his Frankly series, suggested fifteen “unordinary interventions” that any of us could undertake. The aim was not just to ease our personal way through the predicament, but to change the initial conditions of our complex system so that more favorable options might open up in the future. It is the idea that the presence or absence of a small push can eventually lead to enormously different outcomes.

Among the fifteen interventions, I especially liked the invitation to take off your shoes and stand on the ground, literally touching Mother Earth. This simple act, or even the recognition that this option is unavailable, can change one’s view of how much we have lost and how much we might potentially regain. For me personally, I have found that walking barefoot greatly improves my emotional state and literally retunes me to the world. Of course, where you walk matters too.

Now then, as a scientist, I thought I could add a sixteenth intervention: learn a number about Life.

We live in a calculating civilization, but we mostly calculate money and everything related to how our technologies work. With regard to Life, many of us remain largely agnostic. For example, how much Life is there on land and how much in the ocean? What atmospheric composition is optimal for the functioning of our brains? How precisely is our genetic information copied when we pass it to the next generation? At what rate does your body consume energy relative to what the Sun delivers and the biosphere produces?

Connecting our analytical thinking with Life’s functioning can transform how we move through our predicament.

Our atmosphere is an integral part of the environment in which Life thrives and which Life itself maintains. Winds carry water vapor and bring rain. The kinetic energy of these winds is continually dissipated and must therefore be continuously regenerated by some mechanism working in the atmosphere.

Our detective story is pursuing a specific question: can the atmosphere’s observed wind power be explained by differential heating? That is, by the fact that the air is warmer in some places and colder in others, and that this difference sets it in motion.

The Suspect: Differential Heating

Making the atmosphere work is, of course, not the crime. Rather than putting forward an accusation, we want to clarify whether the common claim that differential heating generates all atmospheric wind power holds true.

In the first and second chapters, we considered two “witnesses.” The first was the theoretical study of Lorenz published in 1960. He found that the maximum possible power differential heating could generate was only about half the atmospheric power estimated from observed winds.

The second was the observational study by Romanski and Rossow published in 2013. They directly evaluated the distribution of heating in Earth’s atmosphere and its relationship with temperature. They found that differential heating generated about 1.2 W m^-2. This was again about half the independent estimates of wind power.

The testimony of these two witnesses is strengthened by two facts. First, their statements were made independently. The later study does not refer to the earlier numerical result. Second, both calculations were made within a conceptual framework in which differential heating is assumed to generate all atmospheric power. Their numbers therefore point to a problem within the very framework in which they were obtained.

A witness gives us both a statement and a number. The statement is an interpretation. The number can testify on its own.

Today we will consider a third study. It does not discuss either of the earlier numerical discrepancies and independently arrives at another theoretical maximum below the estimates of actual atmospheric power that it cites. Its author nevertheless regards the agreement as close. This is why numbers matter.

We will then return to the central number: how much power does the atmosphere actually generate, and in what form? Finally, near the end of this post, we will compare atmospheric power per unit area with the power of the human body. I hope readers can take away two useful numbers connecting human and planetary metabolism.

Extracting Maximum Power

Our third witness is Axel Kleidon’s 2021 study, Physical Limits of Wind Energy Within the Atmosphere and Its Use as Renewable Energy: From the Theoretical Basis to Practical Implications. Like Lorenz in 1960, Kleidon was not simply estimating atmospheric power. He was looking for its maximum possible value.

Kleidon represented the climate system with two regions, a warm tropical region and a colder extratropical region. The tropical region absorbs more solar radiation, while the extratropical region absorbs less. Atmospheric motion transports heat between them.

Then we face the same dilemma that we encountered in the first chapter. A greater poleward heat transport carries more energy through the atmospheric heat engine. At the same time, this transport cools the warm region and warms the cold one, reducing the temperature difference that drives the engine. With no heat transport there is no power. If the transport becomes strong enough to eliminate the temperature difference, there is again no power. Somewhere between these two limits, power reaches a maximum.

Lorenz also searched for the maximum power that differential heating could generate. He considered how the distribution of heating and cooling produces available potential energy. Kleidon describes the atmosphere more explicitly as a heat engine and uses the Carnot limit to calculate the rate at which kinetic energy can be generated.

In essence, Kleidon expresses atmospheric power as the product of the poleward heat transport and the Carnot efficiency associated with the temperature difference between the two regions. The two calculations are not identical, yet the underlying question is essentially the same: how much power can differential heating produce at best?

Using satellite estimates of absorbed solar radiation as input, together with an empirical relationship between temperature and outgoing thermal radiation, Kleidon calculated that maximum power occurs at a poleward heat transport of about 32 W m^-2 and a temperature difference of about 30 K. The corresponding maximum power is equal to

G_max = 1.6 W m^-2.

How does this theoretical maximum compare with kinetic-energy generation in the actual atmosphere?

Kleidon refers to previous estimates of atmospheric kinetic energy generation from 2.1 to 2.5 W m^-2 and regards them as similar in magnitude. For a model intended as a first approximation, this may indeed be considered a reasonable agreement. For interpreting the result as an atmospheric maximum, however, the direction of the discrepancy matters. Even the lowest estimate is about one third above the theoretical maximum, while the highest is more than one half above it.

Kleidon discusses several contributions missing from his simple model. These include seasonal variation, the Hadley circulation, tropical cyclones and regional circulations. These qualifications do not diminish Kleidon’s result. On the contrary, the transparency of the model helps isolate one particular mechanism and estimate what it can accomplish. The interpretive difficulty begins when the result is used to conclude that the atmosphere operates close to its thermodynamic limit. Agreement in order of magnitude is not necessarily agreement with a proposed maximum, particularly when the atmospheric estimates exceed that maximum and additional sources of kinetic energy remain outside the model.

Our second witness, the study by Romanski and Rossow discussed in Chapter 2, approached the question from the other direction. Using observations and the Lorenz framework of available potential energy, they estimated how much power differential heating actually generates in Earth’s atmosphere. Their estimate of 1.2 W m^-2 is consistent with Kleidon’s theoretical maximum of 1.6 W m^-2 in one important sense: the actual generation is somewhat lower than the maximum it could theoretically reach.

Taken together, the three witnesses tell a consistent numerical story. Lorenz and Kleidon estimated the maximum power differential heating could generate. Romanski and Rossow estimated how much it actually generates. All three obtained values below independent estimates of atmospheric power.

The witnesses may interpret their testimony differently. Their numbers, however, point in the same direction: differential heating cannot account for the entirety of observed atmospheric power.

Let us now turn to the updated estimates of atmospheric power itself.

In Search of the Right Number

The detective finds one more document that did not enter Kleidon’s comparison: the earlier study by Laliberté et al. (2015). They estimated total atmospheric power at 3.7 W m^-2 from the MERRA reanalysis and 4.1 W m^-2 from the CESM climate model. These larger values widen the discrepancy with Kleidon’s theoretical maximum of 1.6 W m^-2. They are also conspicuously above the range of 2.1–2.5 W m^-2 that he cites.

Here we need to take into account one process that has so far been neglected in our considerations. The atmosphere not only regenerates winds dissipated by friction. It also lifts water.

Water evaporates from the surface, rises to the altitude where it condenses, and eventually falls as precipitation. Raising this water requires work. The rate at which this work is performed is the gravitational power of precipitation. This contribution is easily missed when wind generation is diagnosed from horizontal pressure-gradient work alone. It is estimated independently from the precipitation rate and the mean height of condensation. Every kilogram of water that precipitates must first have been lifted, often through several kilometres.

Laliberté and colleagues calculated the total pressure work of the moist atmosphere rather than horizontal wind generation alone. Their calculation did not isolate water lifting as a separate contribution, but its broader accounting helps explain why their values lie near 4 W m^-2.

We can now return to the winds themselves.

Oh et al. (2026) recently evaluated the Lorenz energy cycle using four global reanalyses. Summing the dissipation of mean and eddy kinetic energy gives estimates of approximately 2.4–2.9 W m^-2.

The shift from the older range of 2.1–2.5 W m^-2 to the newer estimates of 2.4–2.9 W m^-2 may appear modest. In relation to a proposed maximum of 1.6 W m^-2, however, it moves the atmospheric estimates still farther from the theoretical expectation.

And there is another factor that can push the wind-power estimate higher still.

The fact is that kinetic energy generation is concentrated predominantly in the lower atmosphere. Discussing their results, Huang and McElroy (2015) wrote:

“The most prominent sources are located in the mid-latitude oceanic regions below the 800 hPa pressure level, notably in the Southern Hemisphere.”

The vertical profile from our steam-engine paper confirms this pronounced lower-atmospheric maximum and draws attention to a related numerical problem.

Vertical profile of global kinetic energy generation in MERRA-2 for 2023. The resolved pressure levels yield 3.0 W m^-2, of which 2.2 W m^-2 is generated below 500 hPa and 0.8 W m^-2 above. The unresolved surface layer adds to the lower-atmospheric contribution. The decline at the lowest plotted level occurs because much of the land surface has a surface pressure below 1000 hPa. Source: our steam-engine preprint, Makarieva & Nefiodov (2026), Fig. 4.

In MERRA-2, the standard pressure-level fields begin at 1000 hPa. The layer between the actual surface and the lowest resolved pressure level is therefore partly missing. This matters precisely because kinetic energy generation is greatest close to the surface.

The resolved levels give 3.0 W m^-2. Depending on how the missing layer is treated, accounting for it raises the estimate to between 3.2 and 3.5 W m^-2, an increase of up to nearly 20 percent. Our reported estimate is 3.2 ± 0.3 W m^-2, which we can remember as approximately 3 W m^-2 of wind generation.

The gravitational power required to lift precipitating water is independently estimated at 1.1 ± 0.3 W m^-2, which we can remember as approximately 1 W m^-2.

The atmospheric power estimates discussed in this post, grouped according to what they count.

So what have we learned by making our way through all these numbers? Our three witnesses place differential-heating power, including its estimated theoretical maximum, below about 2 W m^-2, while the most recent estimates place atmospheric wind power at about 3 W m^-2. The atmosphere must also lift water, requiring another 1 W m^-2 Total atmospheric power therefore comes to about 4 W m^-2.

The Takeaway Message

Let us now put some flesh on this 4 W m^-2 and make it easier to remember. What are these watts about? How do we measure them?

A watt measures power, the rate at which energy is transferred or generated. Our 4 W m^-2 consists of about 3 W m^-2 of wind generation and about 1 W m^-2 used to lift water.

For water lifting, the calculation is fairly straightforward. We need to know how much water precipitates per unit area and time, and the mean height H from which it falls. Multiplying the precipitation mass flux P by gH gives the water lifting power.

We make partial use of this atmospheric work through hydropower. When precipitation falls on elevated land, some of the gravitational potential energy imparted to the water remains available as the water flows downhill. Hydroelectric plants capture part of this energy. The atmosphere lifts water through several kilometres, while river runoff descends from a mean elevation of only a few hundred metres. Moreover, only part of the runoff passes through turbines. The hydropower we exploit therefore represents a small fraction of the atmosphere’s water lifting power.

Let us now turn to wind generation.

What makes air move is a spatial difference in air pressure. Air molecules continuously collide with and push one another. Pressure increases when more molecules occupy a given volume and when they move more rapidly as temperature rises. Air pressure therefore reflects both how much air is present locally and how hot it is. The differential-heating framework emphasizes temperature differences. In the steam-engine mechanism, condensation removes water vapor from the gas phase and thereby changes the pressure field.

Air is accelerated from areas of higher pressure toward areas of lower pressure. To estimate this wind generation of approximately 3 W m^-2, we need to know the pressure and air velocity throughout the atmosphere.

Of particular interest is the component of air velocity directed from high toward low pressure. The stronger the pressure difference over a given distance, and the faster the air moves in this direction, the more kinetic energy is generated per unit time. When air moves toward higher pressure, the pressure gradient removes kinetic energy from the wind.

Observations from satellites and the worldwide meteorological network are brought together using weather prediction models. The result is called a global reanalysis: a coherent reconstruction of pressure, wind, temperature, and other atmospheric properties across the planet and through time.

Researchers can use these reconstructed fields to calculate the rate at which pressure gradients generate kinetic energy. Integrated over the entire atmosphere and divided by the area of Earth’s surface, this rate is approximately 3 W m^-2.

Imagine dividing Earth’s surface into squares with an area of one square metre and placing the entire atmosphere above each square into a column. Averaged over the planet, the winds in each such column gain kinetic energy at a rate of about 3 watts.

Takeaway numbers, presented barefoot

Is this a lot or a little? To answer, we need a reference value. Usually wind power is considered in the context of human energy needs: how much can we extract from what the atmosphere generates?

I leave this exercise to interested readers. Multiply 3 W m^-2 by the Earth’s surface area in square metres and compare the result with the current rate of energy consumption of our civilization. This will tell us what proportion of total wind generation we would need to harvest to cover all our needs, in the hypothetical case that wind power ceased to be intermittent.

A ready answer and a table comparing different aspects of biospheric and civilizational energy consumption can be found in Energy budget of the biosphere and civilization: Rethinking environmental security of global renewable and non-renewable resources.

Here we will pursue another unordinary perspective. It is entirely unrealistic, but it may provide a lively image that makes our number easier to remember. Imagine that we had to move the atmospheric air and lift precipitating water ourselves, using the power of our bodies. How would we fare?

An adult human body consumes energy at an average rate of roughly 100 W over the course of a day, comparable to two traditional electric bulbs rated at 50 W each. This is metabolic power, most of which sustains the body’s internal functioning and ultimately appears as heat. In our imaginary exercise, however, we shall suppose that all this power could somehow be redirected towards making winds and lifting water.

At 4 W m^-2, each of us would be able to take care of

100 W ÷ 4 W m^-2 = 25 m²

of the Earth’s surface.

The total surface area of the Earth, including the oceans, is approximately 5.1 × 10¹⁴ m². We would therefore need

5.1 × 10¹⁴ m² ÷ 25 m² = 2.0 × 10¹³ people.

That is about 20 trillion people, roughly 2,500 times the present human population. All of them would have to devote their entire metabolic power to moving the air around the Earth and lifting the water that later returns as rain and snow.

As we can see, this is an insurmountable task. If something goes wrong with our winds, we will be absolutely unable to fix it. Accordingly, winds have traditionally been viewed by humans as belonging to the realm of deities. Even in our ultra-modern times, our greatest achievement so far has been to use artificial intelligence to predict how tropical storms move. There is no chance to change what is coming.

Meanwhile, forest ecosystems, and natural vegetation more generally, appear to have evolved ways of regulating these flows. They do so by carefully handling the invisible fuel of the atmospheric machine: water vapor.

We can’t replace the machine. We can, however, preserve natural vegetation and help it recover. In doing so, we can guard ourselves against the worst wind extremes.

Let us cherish our green friends.

Related reading:

We pick up our story from the moment when Edward Lorenz used the most plausible assumptions about the distribution of heating in the atmosphere to estimate the maximum amount of work per unit time (aka power) that this heating could sustain in Earth’s atmosphere. He obtained an estimate that was about half the power independently estimated from the observed winds.

Again, the maximum possible power was already about half the observational estimate.

Before we make a leap of half a century to consider more detailed estimates, I would like to share some thoughts about confirmation bias. When Lorenz set himself the task of calculating the maximum possible power from differential heating, he used the best available data and the most plausible assumptions. Had his simple model yielded the right magnitude for maximum power—for example, 0.03 of solar power versus the observed 0.02—there would have been little reason to search for other assumptions or finer resolution.

Since data are rarely perfect and usually come with uncertainty, how confirmation bias can interfere is as follows. A researcher uses a plausible set of parameter values to test a hypothesis. If the result matches the observations—hurrah, we can publish it. If it does not match, the researcher may look for another set of values for the same parameters, still within the uncertainty ranges and still plausible, although not the first choice. Then, for a certain choice—voilà—the hypothesis matches the observations. This can also be published, but the fact that the first plausible choice did not work may not always be mentioned.

This type of confirmation bias is not very visible, but it can matter. It is relatively innocent in the sense that, if the ultimately chosen set of parameters remains within observational uncertainty, the hypothesis is at least capable of explaining reality. Until it is shown to conflict with other evidence or with physical laws, it remains one possible explanation. However, as uncertainties tighten, the inability of the most plausible parameter values to explain the data may hint at where the error lies.

The fact that Lorenz reported the very low value produced by his first choice suggests that he might have regarded the calculation as robust enough to deserve attention, despite the discrepancy.

Eddies Eating Up Power

Lorenz attributed the discrepancy to assumptions that were too simple:

“Ignoring variations with height and with longitude, and assuming a reasonable value for the mean albedo, we find that the maximum possible rate of generation of available potential energy in such an atmosphere is about 0.01 of the incoming solar radiation.
This is less than the estimated value of the actual rate of conversion in the real atmosphere. If the estimate for the real atmosphere is correct, it follows that we have failed to take some factor into account.”

Half a century later, satellite observations allowed the same question to be examined using more detailed estimates of atmospheric heating. In 2013, Romanski and Rossow published their analysis:

“Our estimates of G are the only ones that are computed from diabatic heating calculated directly from observations and the only ones that decompose G_z and G_e into the contributions from each separate heating process, thus permitting evaluation of the role of cloud processes. Since we calculate diabatic heating from observations, we can link the various contributions to the physical processes that generate them and to the atmospheric circulation, so that we can diagnose, in a physically meaningful way, how the atmosphere’s circulation modifies the spatial distribution of heating away from the simple pattern of net solar radiation.”

Here by G the authors mean generation of available potential energy by differential heating, that is, the vertical red arrow in the schematic picture that we discussed in the previous chapter. G_z is the zonal-mean generation, associated with the meridional distribution of heating and temperature. G_e is the eddy generation, arising from departures from the zonal mean, including the midlatitude eddies.

Uneven heating generates available potential energy by “lifting the atmosphere up.” Kinetic energy is then generated as air flows down along the resulting pressure gradients.

That is to say, in his maximum-power estimate, Lorenz considered only the meridional differences in heating. But at each latitude there are also variations with longitude—in temperature, heat transport, and absorbed and emitted radiation—associated with atmospheric eddies.

Now, in our detective plot, resolving these longitudinal variations could in principle raise or lower the estimate. Lorenz had in fact suspected that the eddy contribution might be negative, but its magnitude could not be reliably established with the data available at the time.

Romanski and Rossow were able to calculate whether the longitudinal heating patterns associated with eddies “lift” the atmosphere further, creating more available potential energy, or instead reduce this energy by preferentially heating colder anomalies and cooling warmer ones.

To keep some suspense before announcing what Romanski and Rossow actually found, let us discuss those eddies. What are they?

If we look at the longitudinally averaged global circulation, we can see three circulation cells in each hemisphere. We already know that warmer air is “higher” than colder air, so the “highest” air resides in the tropics. In the Hadley and Polar cells, the air aloft moves “in the right direction”: from warmer to colder regions, down the pressure gradient.

A very schematic depiction of the zonally averaged atmospheric circulation.

But in the Ferrel cells, squeezed between the “correct” Hadley and Polar cells, the motion is in the opposite direction: from cold to warm—that is, uphill! Kinetic energy is naturally consumed in this uphill motion.

The images below show the instantaneous winds and cloud patterns from which the zonally averaged circulation emerges. The eddies are particularly evident in the Ferrel Cell in the Southern Hemisphere.

The visualizations are from the Earth Nullschool project for July 31, 2026

In the second graph, the white shading shows total cloud water.

The Questions That Nobody Asked

Romanski and Rossow found the zonal-mean generation to be1

G_z = 1.5 W m⁻².

This was already considerably below Lorenz’s estimate of 3 W m⁻². Then came the eddies. Instead of adding the missing power, they contributed

G_e = −0.3 W m⁻².

Thus, the total generation of available potential energy by differential heating was

G = G_z + G_e = 1.2 W m⁻².

The eddies did indeed eat up some power. What does this mean?

Positive G_e is produced when heating strengthens the longitudinal temperature differences: warmer-than-average regions are heated, or colder-than-average regions are cooled. Negative G_e means the opposite: warmer regions are cooled or colder regions are heated, so that the temperature differences are reduced.

This is not the same as the negative kinetic-energy generation in the Ferrel cells discussed above. There, air moves against the pressure gradient and kinetic energy is spent. Here, it is the distribution of heating and cooling that destroys eddy available potential energy.

While these are two different ways in which eddies can be said to eat up power, they are not independent and may in fact help explain why the eddy generation is negative.

Indeed, as we discussed earlier, for a warm location to receive net heating, it must absorb more energy than it emits. In a steady state, the excess heat has to be transported away to a colder location. This is what happens in a heat engine: heat flows from warm to cold, and part of this flow can be converted into work. In the atmosphere, this is the case for the thermally direct Hadley and Polar cells.

There is, however, an important subtlety. When air carries heat away from a warm location, that location, in the steady-state, is left with a positive local heat budget: absorbed solar radiation exceeds longwave emission. At the colder location, the imported heat must be lost by radiation, so the local heat budget is negative. Thus, the circulation does not merely respond to differential heating. By transporting heat, it also helps create the very pattern of differential heating from which the generation of available potential energy is then calculated.

The Ferrel cells work in the opposite way. They do not behave as heat engines, but as heat pumps.2 A heat pump consumes work to transport heat from cold to warm. This is how the fridge in the kitchen works: electric power is used to remove heat from the cold interior and release it into the warmer room.

If most of the eddies contributing to G_e​ are associated with the Ferrel cells, their heat transport should tend to produce the opposite heating pattern: net heating in colder regions and net cooling in warmer regions. This gives negative generation of available potential energy.

After half a century, the neglected longitudinal structure had finally been resolved. It did not repair Lorenz’s low estimate but made it lower.

“If differential heating generates only about 1.2 W m⁻² of available potential energy, how can it sustain the considerably larger power independently diagnosed from the observed winds and pressure gradients?

Is an important heating process missing, are the dynamical estimates too high, or is the premise that all atmospheric work is generated by differential heating incomplete?”

These are the questions that nobody asked.

Outlook

When thinking about the subtitle for this post, I vaguely recalled Agatha Christie’s novel Why Didn’t They Ask Evans? Hence, The Questions That Nobody Asked. But this is not a direct analogy. What seems important here is that there has been almost no discussion of the published mismatch between the prevailing thinking and the data. This is an informative illustration of how our concepts shape what we choose to see and what we choose not to see.

There are many publications evaluating the Lorenz energy cycle. The most recent one I located was published in 2026 and compares atmospheric power across four major atmospheric datasets. Romanski and Rossow are included in the reference list, but the approximately twofold discrepancy is not discussed.

Romanski and Rossow estimated the generation of available potential energy by differential heating at about 1.2 W m⁻², less than half the wind power independently estimated from observed wind speeds and pressure gradients. Thus, the mismatch first encountered by Lorenz in the late 1950s appeared again in the work of Romanski and Rossow half a century later. They may not have recognized that Lorenz had faced essentially the same problem; at least, they did not cite his 1960 work.

Ilya Glazunov. Metro

In retrospect, the progress of ideas is often depicted as a bright individual sacrificing comfort for the sake of truth while confronting an aggressive majority. A visual analogy that came to my mind, also imperfect, is Glazunov’s painting above, with its contrast between the massive dark flow moving downward and the small light movement upward.

But I feel that the actual situation can often be considerably more peaceful and prosaic. Evidence that does not fit may simply fail to attract interest. After all, scientists are free to work on the questions they choose. No individual scientist bears personal responsibility for a mismatch between the prevailing paradigm—all atmospheric work is due to heating—and the data. Many therefore choose to do other things, as though the mismatch did not exist. Eventually, almost nobody knows that it exists and that something should be done about that3.

Then, when a new concept appears—in our case, the proposition that atmospheric motion is driven by condensation—the mainstream may appear as a monolith, although it is not one. From the beginning, the comparison is therefore not entirely fair. The mainstream is presented as though it had no inconsistencies, and authoritative figures may criticize the new concept from that position. Again, this need not result from anyone’s malicious intention. It may simply be how human thought and scientific attention work.

How, then, do things change?

I am struggling to keep the interest of readers who normally come here to read about how green life works its wonders rather than about abstract meteorological concepts. But for me there is no border between science and real life. This is one of the lessons I learnt from Victor Gorshkov. Science is an intellectual window into the beauty of Life. I feel this strongly and try to communicate it here.

Once one sees this beauty, it becomes impossible to unsee it, to forget that when it rains, the atmosphere does its work, and to return to the convenient picture in which heating alone does everything and the vegetation cover is reduced to a surface with a given roughness and color. That’s why we don’t stop.

Nate Hagens recently published a powerful essay about “5D chess”: the need to view our global predicament through several different lenses. At the two most basic levels, we distinguish only between “friend and enemy” or “us and them.” At the third level, we begin to see the entire chessboard. At the fourth, we place that chessboard within the planetary landscape. At the highest level, we add the dimension of time, allowing us to see how the game may evolve.

This resonates with my own attempt to portray the study of atmospheric motion as a great drama composed of many separate stories—rather like Karl Bryullov’s painting The Last Day of Pompeii, in which each small human story forms part of a much larger scene.

What I want to draw your attention to is that we are almost certain to miss something important if we fail to pay attention to the discrepancies that appear, here and there, within the prevailing scientific view. When each discrepancy is considered only at the first two levels—separately and in isolation—it can be quietly swept under the rug. Then, as the years pass and older studies drift into oblivion, it becomes increasingly difficult to notice that these scattered, recurring problems may fit together, forming a larger picture: one in which the prevailing narrative is failing to describe reality.

The digital age, however, has opened new possibilities for recovering forgotten evidence. When we bring these discrepancies to light and trace the connections among them, we begin to discern a different picture—much as in a detective story, where each clue reveals another part of a larger pattern.

The question we are going to pursue may not sound particularly dramatic in itself, but it leads into a much broader set of problems—including, in particular, why the role of vegetation in atmospheric dynamics has been so widely underappreciated1.

Heating and Motion

We know from everyday experience that heating can set air in motion. Above a radiator, heater, or gas stove, warmed air rises while cooler air moves in to replace it. A small circulation begins in the room.

We also want to understand what happens when uneven heating—the ultimate source of which is our Sun—extends over hundreds or thousands of kilometres rather than across a kitchen. To this end, it is useful to imagine the atmosphere as a landscape.

In this analogy, temperature plays the role of elevation. A warmer atmospheric column stands “higher,” while a colder column stands “lower.” This is more than a visual metaphor: the characteristic vertical extent of the atmosphere increases with temperature.2 Warm air expands vertically, while cold air remains more compressed.

A horizontal temperature difference can therefore be pictured as a hillside. Because pressure decreases more slowly with height in the warmer column, surfaces of equal pressure sit higher there than in the colder column. At a given altitude, this creates a horizontal pressure difference. The larger the temperature contrast, the steeper the effective slope and the stronger the pressure gradient.

Now imagine a ball resting near the top of that hill. Once released, it rolls downward. In our atmospheric picture, this downhill motion represents the generation of mechanical power: air moves under the action of pressure gradients, converting energy stored in the temperature contrast into kinetic energy.

In doing so, the circulation tends to weaken the very contrast that made the motion possible.

Heating can act in the opposite direction, rebuilding the hill.

If heat is added to the already warmer region, the high side rises still higher. The temperature contrast grows, the slope becomes steeper, and more power can be generated as the atmosphere moves “downhill.”

If, however, the same heat is added to the colder region, the lower side rises toward the higher one. The temperature contrast weakens, the slope becomes gentler, and less power becomes available.

The analogy therefore gives us something more than a picture. We can estimate the two sides independently: how rapidly heating builds the atmospheric slope, and how rapidly atmospheric motion runs it down. In a steady state, the two rates should match. In the language of the figure, the red and black arrows should represent equal amounts of power.

The First Mismatch

Our story begins around 1960, with Edward Lorenz as its first protagonist. One of the most influential atmospheric scientists of the twentieth century, Lorenz was among the first to ask quantitatively how much kinetic energy the atmosphere could generate from differential heating.

At that time, atmospheric measurements were far less precise than they are today. Observations indicated that the power generated within the atmosphere and the power dissipated by friction were at least of the same order of magnitude, as they must be on average in a steady state. But the uncertainties were too large to establish convincing numerical agreement. Early estimates of the power generated by differential heating differed by severalfold.

Lorenz therefore attempted something more robust. Rather than relying only on uncertain observational estimates, he asked how much power differential heating could possibly generate on Earth. He sought an upper limit.

To understand his reasoning, we need to look more closely at what differential heating actually means.

Our planet receives solar energy unevenly: much more in the tropics than near the poles. It also emits thermal radiation unevenly, although the variation with latitude is smaller.

Annual-mean radiation balance by latitude. Earth absorbs much more solar radiation in the tropics than near the poles, while outgoing longwave radiation varies less strongly. This leaves a radiative surplus at low latitudes and a deficit at high latitudes. From Goosse et al., Introduction to Climate Dynamics and Climate Modeling, Fig. 2.14; NCEP–NCAR reanalysis data from Kalnay et al. (1996). Reproduced under CC BY-NC 4.0.

At every location, we can compare the energy received with the energy emitted. If the two balance, the long-term net heating there is close to zero.

This is what would tend to happen if air did not move heat between regions. Each latitude would approach its own local radiative–convective equilibrium: it would emit approximately as much energy as it received, and the net heating available to generate atmospheric power would vanish.

Once the atmosphere moves, however, it transports heat from warmer regions toward colder ones. The warmer regions receive more energy from the Sun than they emit to space, while in the colder regions the opposite is true. This contrast between net heating and net cooling is the differential heating considered by Lorenz.

We therefore face a dilemma.

If there were no horizontal air motion, there would be no heat transport and hence no differential heating, even though the temperature contrast between warm and cold regions could be large. The atmospheric hill would be steep, but nothing would move down it, so no power would be generated.

At the opposite extreme, very strong air motion would transport heat so effectively that it would smooth out the temperature contrast. The hill would be flattened, leaving little pressure gradient to drive the winds. Again, power generation would tend toward zero.

Maximum power must therefore occur somewhere between these two limits, where both the temperature contrast and the motion-driven heat transport remain finite.

Lorenz estimated this maximum. Remarkably, even the maximum power that differential heating appeared capable of producing was only about half as large as the observational estimate then available.

As Lorenz himself put it3:

“Ignoring variations with height and with longitude, and assuming a reasonable value for the mean albedo, we find that the maximum possible rate of generation of available potential energy in such an atmosphere is about 0.01 of the incoming solar radiation.
This is less than the estimated value of the actual rate of conversion in the real atmosphere. If the estimate for the real atmosphere is correct, it follows that we have failed to take some factor into account.”

In the language of our landscape analogy, even the fastest possible rebuilding of the hill seemed insufficient to explain how rapidly the atmosphere was running it down.

Yet observational estimates were still highly uncertain, and the question of whether some process other than differential heating might generate atmospheric power was not even posed. The mismatch therefore attracted little discussion and was soon overshadowed by a more reassuring conclusion: that the atmosphere operates somewhere close to its maximum possible power—although just how close remained as uncertain as the observations themselves.

Interlude: Why Atmospheric Power Matters

The next mismatch appeared more than half a century later, in the mature satellite era. We will come to it in the next post.

For now, as in a good detective story, let us pause the main narrative and add a few considerations that give the investigation a broader scientific and cultural context.

Why should we care about the precise value of atmospheric power?

Atmospheric power tells us how rapidly the Earth system can regenerate atmospheric motion against the friction that continually dissipates it. When we turn off the gas stove in the kitchen, the small circulation above it fades: the motion dissipates and is no longer regenerated.

Many important features of Earth’s climate depend on how energetic the atmospheric circulation is. Many readers of this blog are environmentally concerned citizens and know that excess atmospheric CO₂ contributes to global warming. Far fewer people realize that climate models can produce substantially different global temperatures at the same CO₂ concentration, depending on the circulation and the resulting transport of heat.

I discussed this issue, together with figures from the relevant papers, in The Super Greenhouse Effect and Winds as Global Temperature Controllers.

Now follow the logic. In the prevailing account of climate change, CO₂ is the primary driver, while many other changes are treated as feedbacks to the warming caused by CO₂. Atmospheric circulation is expected to respond as well. But if we do not understand what drives that circulation—and what role additional heating actually plays—we are very likely to misunderstand, and therefore mispredict, changes in atmospheric circulation.

This matters because shifts in atmospheric circulation and their teleconnections are increasingly discussed as possible contributors to abrupt changes in global temperature that climate models have not fully anticipated or explained.

It also matters for anticipating changes in large-scale coupled systems, including the Atlantic meridional overturning circulation and its relationship to the Gulf Stream.

But this is only part of the problem.

More seriously, if we do not understand the relative roles of heating and other drivers of atmospheric motion, we may overlook the circulation response to disturbances other than rising CO₂—most importantly, changes in vegetation cover on land. We may then devote enormous attention to mitigating CO₂-driven change while continuing to neglect the climatic consequences of land-cover change.

This possibility is especially important because, as we discussed in Atmosphere as a Steam Engine: New Results, the process that we argue has been overlooked as a contributor to atmospheric power is water-vapour condensation. Over land, the availability of water vapour is closely tied to vegetation.

Whether a permaculturist restoring degraded land or a conservationist protecting resilient natural ecosystems contributes to climate stability—and whether such work deserves recognition and urgent support—depends strongly on whether we correctly understand the roles of heating, condensation, and vegetation in atmospheric circulation.

I value this line of inquiry precisely because the path from a seemingly abstract academic question to practical policy is far from obvious. To find the right solutions, we may have to begin much further back—with seemingly abstract questions about how the atmosphere works—and reconsider the entire foundation on which decisions are made. This work has brought me and my colleagues into contact with remarkable people willing to follow such a long and non-obvious path toward solutions whose significance may reach far into the future.

As Nassim Nicholas Taleb illustrates in The Black Swan, those who prevent catastrophes may receive no recognition precisely because the catastrophes never occur. They themselves may never know whether anything was truly prevented. For any effort whose value is not immediately obvious, the reward may therefore simply lie in being understood and appreciated by like-minded people.

With that, I want to express my sincere gratitude to all readers of this blog—and my deepest gratitude to those who have found ways to support my inquiries.

Please stay tuned for the continuation of our journey.

Related reading:

The Yenisey River provides a perfect space for practising spaciousness—in every sense of the word.

We have returned from the taiga and gone back to work, but I feel I need to share something before I can move forward. It is always overwhelming, and it is difficult to find the right words to convey the significance of wild nature—and how much it matters to us, even when we do not know it.

So perhaps I will not even try this time. I will simply share a few scattered feelings and photographs.

You arrive by boat during high water. There is no snow left in the forest, but much ice remains along the banks.

No greenery yet—only a few first flowers among last year’s dead grass.

Then, over the next three weeks, comes the spring explosion. Everything bursts into life and grows, seemingly frantically, but in fact according to some intricate set of rules. You can see how powerful and unstoppable natural life is.

The same place, three weeks apart

You have to take care of food almost all the time: catch fish, prepare it, and try to build up a reserve for the days when there is no catch. It is a great deal of work, and it is hard to imagine that our ancestors could have survived here on catches as small as those of today, given how imperfect their tools were. Yet fish are still abundant enough to sustain you.

Then there is the bear.

This year we met one. We were returning to our cabin after a long walk when we suddenly saw bear tracks leading in the same direction, sometimes printed over our own footprints from the outward journey.

“Doesn’t this mean that he walked after us, and now we are following him?”

“Well, yes. But look—isn’t that a bear over there?”

And it was, about seventy metres away, down by the river.

In Thinking Like a Mountain, Aldo Leopold wrote that a deer herd lives in “mortal fear of its wolves,” just as a mountain lives in “mortal fear of its deer.” Seeing a large predator that could tear you apart if in a bad mood awakens this fear. In small doses, it shakes you inwardly and summons hidden resources.

In larger doses, it can alter the course of a life. Dostoyevsky survived a mock execution after being sentenced to death, an experience that shaped his later work. Victor Gorshkov, born on this day in 1935, survived a terrorist bombing aboard an airliner shortly before turning from theoretical physics to the study of life.

The danger makes correct behaviour suddenly important.

Do not run. Running may trigger the instinct to pursue, and the bear may follow.

Our bear was in a good mood. He was eating plants and gradually moving away from us. Then he crossed the river, leaving our path home clear.

Home, here, means a hunter’s cabin in the forest.

Near this cabin stood a small banya, or bathhouse. Unusually, it was locked. Earlier in the spring, a bear had smelled some food stored inside and wanted to get in. Since the door was locked, he opened it in his own way, pulling an entire piece of timber out of the wall and wreaking havoc inside.

Among the other neighbours who appeared were a young moose, many chipmunks, and birds of many species. The birds sang beautifully as spring unfolded into summer.

There are also all kinds of flowers: peonies, lilies, orchids, wild roses.

The taiga teems with flowers, like Eden.

When the spring floodwaters receded, aquatic plants began to emerge, trembling in the gentle current. I have always been enchanted by their bowing, as though they were trying to tell us something, to alert us to something philosophically important.

A friend asked, “How far away is the nearest person?”

Not very far, perhaps ten kilometres away, on the Yenisey, there is a small settlement whose inhabitants maintain the river’s navigation beacons. But reaching them would take an entire day, because the taiga is almost impenetrable. And when you also have things to carry, walking out to civilization takes at least three days.

You have to cross many bogs and wetlands and climb over a succession of ridges. The terrain is difficult and complex. Walking through all this creates a peculiar mood of green immersion.

“An echanted tree” — a point where we lost our way several times

This summer was drier and warmer than usual. Our river grew shallow and warm, and the local trout retreated to the cooler waters of the Yenisey. There were no fish to catch, so we lived on the fish we had smoked earlier.

Yet the vegetation, undisturbed by human exploitation, seemed to be coping well with the unusually dry conditions. Given nature a chance. Give it space to breathe.

The mosquitoes make it impossible to leave much skin exposed, so you have to remain fully covered even in the heat, while walking and carrying your things. By the time you finally emerge from the taiga to the nearest village, you need at least a couple of days simply to recover.

Aldo Leopold concluded Thinking Like a Mountain as follows:

We all strive for safety, prosperity, comfort, long life, and dullness. The deer strives with his supple legs, the cowman with trap and poison, the statesman with pen, the most of us with machines, votes, and dollars, but it all comes to the same thing: peace in our time. A measure of success in this is all well enough, and maybe a requisite to objective thinking, but too much safety seems to yield only danger in the long run. Perhaps this is behind Thoreau’s dictum: In wildness is the salvation of the world. Perhaps this is the hidden meaning in the howl of the wolf, long known among mountains, but seldom perceived among men.

My own, non-poetic take is less radical and more positive. Wildness is extraordinarily beautiful, complex, and difficult. Modern people have a unique opportunity to preserve it, experience and enjoy its breathtaking beauty, and then return to the comforts of civilization. What is needed is a rethinking of priorities.

Related reading:

The original conversation can be watched here:

The text below has been edited for readability. This is my last scheduled post while I am away in the wilderness. As you read it, I am still offline, thinking that today my post should appear — if the civilization from which we have temporarily escaped is still functioning. So I have decorated our conversation with views of the Siberian wilderness in June.

Coming to forests from theoretical physics

Kathy: From MEER, Mirrors for Earth’s Energy Rebalancing. This is the MEER podcast.

Arjana: We explore climate science, systems thinking, and real-world solutions. Today we are talking about forests not just as carbon sinks, but as engines of planetary circulation.

Kathy: Our guest today is Dr. Anastassia Makarieva, a theoretical physicist from the Petersburg Nuclear Physics Institute in Russia.

Arjana: She is known for her work on the biotic pump theory: the idea that forests do not just respond to climate, they actively influence atmospheric circulation and rainfall patterns across continents.

Kathy: Anastassia, welcome.

Anastassia: Thank you, Kathy. Thank you, Arjana. It is my pleasure to be here.

Arjana: We’ll first get into your personal journey and origins. You are a theoretical physicist by training. How did you end up studying forests and atmospheric physics?

Anastassia: I graduated from the Faculty of Physics and Mechanics of the Leningrad Polytechnic Institute, but my department was the Department of Biophysics. Thus, my training was quite broad. It was not exactly training in the life sciences, but it gave me some glimpses into them.

The most important influence was one of our professors, Victor Gorshkov. I later became his collaborator. He taught a unique course on human ecology and biosphere stability. Through his work and through this course, I became acquainted with systems thinking, which you’ve already mentioned, and with a broader view of sustainability, biosphere stability, and how natural ecosystems matter for the Earth’s climate and environment.

It was due to his mentorship that I gradually came to study these things. He also worked as a theoretical physicist at our institute, and I joined the same theoretical department. I am very proud to be part of it. It provides a unique atmosphere of free research. This does not mean that we are very well financed, but research freedom is deeply respected.

Arjana: So you were not coming from traditional meteorology. You were beginning from physical principles.

Anastassia: Yes. I think this is one reason why we could develop something truly original. That it is original is not disputed: not everybody agrees with it, but nobody disputes its originality. It was a different perspective on these problems.

Arjana: Exactly, it’s so great when scientists from different backgrounds come and look at the climate problem from different perspectives. It is very helpful.

Kathy: Exactly, and I would say that, in a similar way, Dr. Ye Tao, the founder of MEER, also began with a chemistry and physics background before turning to the climate change challenge. This gave him a unique approach: tackling the three-dimensional problem of a heating atmosphere with a two-dimensional strategy of surface reflection.

Anastassia: This is a very large topic, because there are also social laws that govern science as a social enterprise. There are social forces that tend to push scientific communities toward groupthink. For example, when people vote to choose a new colleague, if there is even a small tendency to accept someone who thinks similarly, the system can spontaneously evolve toward more uniform thinking. This does not require bad intent or conspiracy; it is simply how social systems may work. That is one reason why disruptions so often come into a discipline from outside.

What a wild forest teaches

Kathy: Moving back to your area of focus, we have read that you spent summers in the northern Russian forest. How did those experiences shape your thinking?

Anastassia: This was a very important part of my education — education in the deep meaning of that word. What I now understand as the principal property of natural ecosystems is their fantastic complexity.

We do not have anything comparable in our urban life. We wake up and see a table, a chair, familiar human-made objects. But in a natural forest there are flows of energy and matter, and innumerable living creatures participating in them, genetically programmed and shaped by millions of years of evolution. They are doing very different things. Some are synthesizing organic matter, while others are decomposing it at the same time. Yet this does not produce havoc or chaos. It works smoothly and maintains natural beauty.

For me, studying natural ecosystems only became possible because I had seen this and had been immersed in this ecological action. One cannot really understand such a system in full; but one can, in a modest way, participate in it, belong to it, observe it from within. It formed in me a sense of complexity, and a sense of awe and modesty with which one should approach the analytical study of nature.

This is crucial, because one understands that a natural ecosystem cannot be described by one or two, or even one hundred, numbers. One has to think first of all about function: what these systems are doing and how they are organized in a highly complex, information-rich way.

And it is not enough to go to a neighboring park and see “nature” that is under human control. One needs to encounter a place developing by itself, through primordial forces. Then one sees the interplay of abiotic and biotic phenomena. For me personally, this was very important.

Kathy: That is a beautiful connection between observation and theory that you bring together in your work. I do share your passion and love for those natural forests, and the awe that one feels when one is in a remote forest.

Anastassia: Yes. It is a very unusual feeling of belonging and immersion. It gives one an impetus to go further: to try to understand, and to bring our own human enterprise into balance with this magnificent thing that is nature.

What is the biotic pump?

Arjana: Let us turn to the biotic pump. For listeners who have not encountered it before, what is the biotic pump theory?

Anastassia: The biotic pump theory is about how forests draw moisture inland.

There is an interesting story behind it. We had a colleague in the Amazon, Dr. Antonio Nobre, who knew about our other work on how natural systems regulate climate and the environment. We had been doing research related to carbon dioxide and climate stability. He said, in effect: look at the Amazon — we have this majestic water cycle and this majestic forest. It cannot be that they are unrelated. If you are studying biotic regulation, please come and explain what is going on here.

So from the very beginning it was a challenge from a friend. We began by asking: how can a forest do this? Life emerged from the ocean; at some point it had to march inland from the coast. How did it bring rain with it?

Today we can observe that, in the great forested regions, precipitation does not decline from the coast toward the continental interior in the way one would expect over non-forested regions. If air goes inland, rains out, and this water drains back to the ocean as rivers, then rainfall should diminish inland. But in the large forests this is not what we see.

So we thought: is there a physical mechanism by which forests could arrange to have enough rain to compensate for river runoff? This question arises because land differs fundamentally from ocean in that land is continuously losing water: it is elevated above the ocean, and due to gravity water returns to the ocean as runoff, and does so very rapidly. Therefore, to remain wet, land must receive an atmospheric inflow of moisture. There is no other possibility. The question is: how is this inflow maintained?

What we proposed is that, when water vapor condenses and falls out as rain, there is less gaseous matter in the atmosphere and pressure drops. It is as simple as that. For some reason, this effect had not received sufficient attention. We quantified it theoretically and showed that it is powerful enough to explain a potential forest impact on atmospheric circulation.

A forest transpires. During photosynthesis, a green leaf must open its small pores to take in carbon dioxide molecules. While these pores are open, many water vapor molecules leave the leaf. The atmosphere becomes moist. A moist atmosphere has fundamentally different dynamic properties from a dry one: different processes become possible.

When a forest keeps the atmosphere moist, the air can rise and cool; water vapor then condenses and precipitates. This condensation produces a pressure drop, and air moves toward that pressure drop from adjacent areas. If the adjacent area is the ocean, and the forest borders the ocean, moist oceanic air flows toward the forest and further into the continental interior.

That is the main idea of how the biotic pump functions.

Arjana: That is fascinating. So, as a brief summary for our audience: trees transpire vast amounts of water vapor; this vapor condenses; pressure drops; and moist air is pulled inland. So, rather than heat being the only driver of wind, your argument is that condensation itself can generate a pressure drop and draw moist air inland. Is that correct?

Anastassia: It is not that heat has no role. It does. What was new in the biotic pump theory was demonstrating that the pressure-drop mechanism associated with condensation and precipitation is significant.

Previously, this had not been shown, and because of that it was, and still is, assumed that forests cannot influence atmospheric dynamics in this way.

The mainstream view emphasizes differential heating: different amounts of solar energy arrive at different places, and this drives atmospheric currents in various ways. In that framework, forests can change this or that, but they do not crucially alter atmospheric dynamics, because their heating effects are considered relatively small.

Once we focus on the pressure drop related to condensation and precipitation, however, a new physical argument appears: forests can be crucial for atmospheric dynamics because they maintain the moist conditions in which this mechanism operates.

Deforestation and the possibility of abrupt change

Arjana: If this theory is correct, what does it change about how we should think about deforestation?

Anastassia: The biotic pump is part of a larger framework showing how forests matter for climate stability. First of all, if we destroy forests, we significantly undermine the stability of the terrestrial water cycle. This is a tragic prospect at a time when more and more people experience water shortage.

We believe that there has already been a major event in human history: a major desertification event caused by the destruction of the biotic pump. It occurred in Australia, which used to be green.

Australia was not, of course, a rainforest continent like equatorial Amazonia. Its geographical position is different: much of it is situated in a region where dry air tends to descend. Nevertheless, several tens of thousands of years ago Australia was much greener. For example, species of tree kangaroos that today occur only in moist tropical forests closer to the equator have left remains over much larger regions of the continent. Scientists now find their remains throughout Australia.

But when the first people came to the continent, approximately 40,000 years ago, there was, at approximately the same time, an abrupt shift to arid conditions. It was not caused by any large-scale climatic perturbation that would have been registered. Thus, it remained practically unexplained.

From the biotic pump viewpoint, if these people used fire for hunting, as we know they did, and if they burned forests along the coast where they originally settled, this could have cut the remaining tree cover — that is, the remaining biotic pump of the inner continent — off from oceanic moisture. Aridity could then have followed almost instantaneously on a geophysical time scale.

This proposed mechanism is less plausible directly at the equator, where rainfall is strongly favored by geophysical conditions and the presence of warm ocean. But where the background geophysical conditions are less favorable, such a flip may occur if vegetation is destroyed. We do not know exactly where this boundary lies or what level of disturbance may cross the threshold.

An ecosystem does not necessarily degrade linearly. As a regulatory system, when disturbed, it initially tries to compensate. One can therefore see the disturbance growing while, apparently, little changes. But internally, the resistance required to maintain homeostasis increases. The system struggles harder and harder, and then, at a certain point, it may break down.

This is especially relevant to the water cycle, because the water cycle involves many positive feedbacks that can proceed unchecked when biotic control is lost. Forests are makers of a dynamic equilibrium favorable to our existence. This is how we should view them. They are not just standing there. They are working. They are functional. When we destroy them, we destroy a function that keeps our planet habitable.

Arjana: That is very powerfully put. A previous guest from Brazil spoke about Indigenous rights and about seeing forests and trees as protectors. There is a resonance with what you are saying about forests as workers and protectors.

Anastassia: I think there is much true knowledge that people can gather when they live in direct contact with an ecosystem.

But it is also important that forests are not only relevant to the local water cycle: the Amazon forest is not important only for Brazil, nor the boreal forest only for Eurasia. Because these forests are so large, and because atmospheric circulation depends on them, they can have an important global impact.

This impact is not well understood or incorporated in global climate models. Climate models were developed primarily to describe how climate responds to increasing carbon dioxide, and they do a reasonable job with respect to that purpose: one does not find models predicting cooling from increased carbon dioxide; they robustly predict warming, although by differing magnitudes.

But when one looks at what models predict for deforestation in relation to the water cycle, there is no robust response and no clear constraint — no clear idea of what it should be. Some predict reduced streamflow, others increased streamflow, and the magnitude of the response varies greatly. Thus, they currently provide no guidance on the climatic importance of forests.

That is why we believe there is ample room for new insights and for a reconsideration of how we think about the importance of forests.

Are the Amazon and boreal forests vulnerable?

Arjana: How vulnerable are the Amazon and boreal forests now, in your view?

Anastassia: I can speak with more direct knowledge about boreal forests, although I believe the same central concern applies to the Amazon. My view is that intact forests, if not logged or burned, have a very high chance of withstanding the climatic changes now being imposed on them. For many forest species, a change of a few degrees is within the range of conditions they can naturally experience. There are, of course, ecosystems that are far more immediately vulnerable, such as coral reefs; I am speaking here specifically about forests.

The grave problem is what happens when we log a forest. We strongly disrupt the water cycle and the local moisture regime. We open the canopy. There is more wind, and therefore more uncontrolled evaporation rather than transpiration. Transpiration is a process controlled by the tree; evaporation from an opened, disturbed surface is not controlled in this way. When the canopy is opened, moisture can be rapidly lost. The forest dries, and once it is dry it becomes susceptible to bark beetles and other disturbances. Trees die; dead and weakened forests burn. A whole chain of disasters can begin with human interference.

Unfortunately, the idea of “sustainable forestry,” born roughly one or two hundred years ago, is based on neglect of the climate function of forests. Sustainability came to mean: we may cut as much timber as the forest regrows.

But think of a natural forest without humans. It does not “regrow” in this economic sense. Like the biosphere as a whole, it exists in a stable equilibrium. Every tree that dies gives life to an enormous number of creatures, all of which do something in the ecosystem. Consider, for example, the production of biological aerosols that participate in cloud formation — a process in which bacteria and fungi are involved.

In a natural forest, the annual increment used as a forestry measure is close to zero because the forest is not a crop; it is a stable living system. When we cut it, it begins to regrow, and then it has an annual increment. Sustainable forestry brings the forest to the condition where this increment is at its maximum, and keeps taking the maximum of what it produces.

It is as if we took a person and exploited him or her so as to obtain the largest possible output of work, leaving no free time, no relaxation, no resources for recovery. This is what we have been doing to the European forests for two or three centuries. Forest trees can live for two, three, or four centuries. Thus, for an entire forest lifespan, we have not given these forests a moment to breathe. We have continuously exploited them and called this sustainable.

What happens to a person exploited in this manner for an entire lifespan? Of course he or she breaks down. This is what is happening now with European forests: they are breaking down. Climate change is a trigger, but even without climate change, such overexploitation cannot continue indefinitely.

Now, when forests are in trouble under climate change, we should exploit them less, not more. They cannot simply give us pellets in order to become our “renewables.” If we continue in this way, we will lose them forever. What we should be doing is withdrawing from forests and allowing them at least one hundred years — which is very little in forest time — to have some time for themselves.

Kathy: That is a powerful metaphor and a sobering picture.

Anastassia: Yes. It is like saying: we provide this person with enough food, so the caloric value is adequate; why, then, did he or she become ill? Every complex system must have resources for its inner resilience. We are depriving forests of these resources.

How can the biotic pump be tested?

Arjana: What would it take to properly test the biotic pump hypothesis?

Anastassia: This is something we continuously think about. We cannot destroy an entire forest simply to see what happens. Fortunately, the Amazon forest is still resilient and still functional. Even if we see a decline in moisture inflow during the dry season, indicating that the system may already be close to the brink, this decline is still compensated during the wet season. We can see the forest attempting to rebalance.

Forests are extraordinarily complex. Therefore, we need indirect ways to show that the physical mechanism is correct: first to establish the physics, and then to apply that understanding to forests with greater confidence.

This is why we have studied tropical cyclones. Tropical cyclones are remarkable phenomena with intense condensation and precipitation in their centers. Unlike the Amazon forest, of which there is only one, tropical cyclones are numerous, so we have statistics. We can measure them and ask whether condensation of a given intensity produces pressure gradients of the magnitude predicted by our theory. This is what we have been doing, and we have found good agreement.

Another possibility is to study the general atmospheric circulation — the great circulation cells, such as the Hadley cells — and ask whether the observed global precipitation can drive the observed winds according to the proposed physics. This also gives good agreement. We proceed step by step, trying to show the scientific community that this is a valid proposition.

Kathy: You have also suggested that forests may influence cyclone formation. How might this work?

Anastassia: This remains to be studied in greater depth. The basic idea is that the fuel for tropical cyclones is atmospheric water vapor. Imagine a great forest drawing atmospheric moisture toward land. If there is a persistent outflow of moisture from the adjacent ocean toward the continent, tropical cyclones may have less water vapor available for their development.

This was one of the ideas that occurred to us in the early development of the concept [see Makarieva and Gorshkov 2010 and Makarieva and Gorshkov 2013]. If one looks at tropical cyclone tracks, one notices that the Atlantic Ocean between the Congo and Amazon forests is effectively free of tropical cyclones. There are no regular tropical cyclone tracks there. If one looks at how precipitation changes annually between the two forests, there is also a certain alternation: at some times the Congo forest receives more precipitation, at other times the Amazon receives more, but at all times little appears to be left for cyclone development.

[see also Sheil D. (2026) How Forests May Reduce the Incidence of Destructive Tropical Cyclones, Hurricanes and Typhoons. Forests, 17(3), 359; https://doi.org/10.3390/f17030359 — AM]

Of course, this is an a posteriori explanation. It is not yet a bulletproof demonstration. Other explanations are offered — for example, that there is simply insufficient space between the two continents for cyclone development. But at least one such event has occurred in the South Atlantic — Hurricane Catarina in March 2004 — indicating that tropical cyclone formation there is possible.

Arjana: Even as a hypothesis, it suggests a new way of thinking about forests: as possible stabilizers of global atmospheric systems.

Anastassia: Yes. And the argument extends further. Today there is intense discussion in climate science about possible catastrophic changes in ocean circulation: whether important oceanic flows may weaken or collapse, bringing drastic climatic changes. If atmospheric circulation depends substantially on forests, then disrupting a forest system as large as the Amazon could also have consequences for oceanic circulation. This is one further reason to recognize that these systems are interconnected.

Forests and the vertical transport of heat

Anastassia: There is another related aspect that we are studying: the role of forests in the vertical transfer of heat.

When forests transpire, energy that would otherwise heat the surface is used to evaporate water. When the vapor later condenses aloft, latent heat is released there. If the air remains aloft long enough, part of this energy may radiate to space from a higher level than it would if it were absorbed and converted to thermal radiation near the surface.

The important point is that this effect depends on circulation. If long-range circulation is replaced by small circulations in which air rapidly descends, the cooling effect may be weakened, as the air warmed by latent heat is brought back toward the surface.

If, however, the air remains aloft long enough for energy to radiate away, there will be a cooling effect. This is not an instantaneous process: the atmosphere can radiate only a finite amount of energy per unit time. The biotic pump represents a long-range circulation, with air travelling thousands of kilometres in the lower atmosphere and thousands of kilometres back aloft. Such circulation can keep air warmed by latent heat in the upper atmosphere for a long time. If we disrupt it and replace it with many small circulation patterns in which air descends quickly, this alone will warm the Earth.

This is a radical proposition, but it is one we have published and that can be examined. My view is that we need to open our minds to see how forests matter. They matter very greatly.

Criticism, inertia, and scientific change

Kathy: You have mentioned that your ideas are somewhat controversial in climate and atmospheric science. Scientific revolutions often do take time, especially when they challenge foundational assumptions. How do you avoid becoming discouraged by critics?

Anastassia: I think critics are a very good thing. I am not discouraged by criticism. In the first years I was a little surprised that developments did not proceed faster, but now, having more experience and having learned more about atmospheric science, I understand that science can move very slowly.

There is an example that has personally impressed me. More than a century ago, Margules posed the problem of how atmospheric potential energy can be converted into motion. Only decades later did Lorenz formulate available potential energy in the form that became central to modern atmospheric energetics.

The central problem is not necessarily criticism. Everybody in a scientific community is already doing their own work, and there is often little incentive to change direction. The life of a scientist is difficult: one needs grants, publications, and a place within a community. This is partly sociological, and partly the natural inertia of scientific development.

Criticism itself is positive because it means that one is being noticed. People do their best to show that one is wrong. Even if a critic goes away convinced that one is wrong, one is left with their arguments. One can consider them, see whether one is right, strengthen the argumentation, and emerge with a better understanding.

The main enemy is not criticism; it is non-existence — when a body of knowledge is treated as though it were not there. This undermines the essence of the scientific process.

For example, there are competing theories of tropical cyclone formation. We published a critique of a major theory in one of the central journals of meteorological literature, the Journal of the Atmospheric Sciences. The anonymous reviewers were surprised by its implications; yet, after publication, the broader community remained largely silent. It is often easier to speak against the mainstream when one does not belong to that community than from within it.

This is unfortunate. But science itself is so exciting that it keeps us going.

What keeps one working?

Arjana: After years of debate and persistence, what keeps you motivated?

Anastassia: I am motivated by two things.

First, I hope — and perhaps there are grounds for this hope — that society may reach a new stage of understanding itself, in which this knowledge can contribute to a new attitude and new ethics, if we survive the present predicament. Together with many other people, we are doing our small part to build that possible future, and to protect the beauty that is still here.

The second reason is more individual: the science itself is so exciting that I would not want to do anything else. Even when it is difficult to move forward, this is what keeps us going.

Arjana: It is exciting and also crucial. Doing this work can feel like helping to build the future.

Anastassia: Yes. Many of us share the feeling that this may be useful for the future — that, in some modest way, we may be contributing to building it. So many negative things are happening. We have little to rely upon except our intellect: we need to understand what is happening, and to change.

Kathy: Anastassia, thank you very much for putting your passion into action and for helping to illuminate the vital roles that forests play in the climate system. We wish you well in your continued research and advocacy, and hope to hear updates from you.

Anastassia: Thank you very much. Good luck with your important work as well.

Related reading:

We are losing nature, and as a society we generally do not seem to care enough. From my corner of reality, I see clearly that this is profoundly wrong, and I am constantly looking for ways to explain why. I recognize some repetition in this blog’s title with a previous one, “Simplicity and Complexity, Doing and Non-Doing, Restoring and Preserving,” but I have kept thinking about this, and complexity is central.

What is Left?

By “what is left,” we mean natural ecosystems that still exist, seemingly for their own sake — ecosystems that are either not under direct human exploitation or, where exploitation has occurred, remain capable of self-recovery. This capacity for self-recovery is one of the defining features of wild nature.

In the forest zone, one useful operational measure of “what is left” is the concept of Intact Forest Landscapes (IFLs): large, unbroken natural landscapes showing no signs of significant human activity and large enough to maintain native biodiversity, including viable populations of wide-ranging animals. Technically, these are areas of at least 500 km², with a minimum width of 10 km.

The map below shows the remaining extent of Intact Forest Landscapes in 2025 and their loss over the preceding twenty-five years.

Fig. 2 from “INTACT FOREST LANDSCAPES EXTENT AND CHANGE, 2000-2025” by Potapov P., Turubanova S., Glushkov I., Zhuravleva I., Komarova A., Goldman E., Rosoman G., Yaroshenko A.: IFL extent for the year 2025, IFL area reduction from 2000 to 2025, and boundaries of geographic regions used for the analysis.

In 2000, the world still had about 12.8 million km² of such Intact Forest Landscapes. By 2025, this had declined to about 10.9 million km². What remains now occupies only 8.4% of the Earth’s ice-free land area and contains about 21% of global tree cover. Most of these remaining intact forests are concentrated in the Amazon and Congo basins and in the northern boreal forests, particularly in Canada and Russia. These remaining wild forests are our real treasure.

Fig. 5 from Potapov et al. 2025: IFL area loss 2000-2025 as a percentage of the year 2000 IFL area by country.

Viewing these maps invites numerous thoughts.

The red mark that catches the eye in Europe indicates the complete loss of Intact Forest Landscapes in Romania. There was not much there, and now there is nothing. Europe does not have much wilderness left, but it is still losing what is left.

At the same time, Europe has taken a visible course toward rewilding, and its initial efforts readily attract media attention. Restoration is valuable. But what does it tell us if we cannot preserve what we aim to restore? Can restoration become an illusion of doing — a way to avoid facing the truth that we remain unable to preserve what is left, or even to recognize its significance?

Another line of thought is more positive. Intact Forest Landscapes are not all we have. There are treasures invisible on this map: forests that were disturbed in the past but still retain the potential for self-recovery. Given time and protection, they may again become wild forests — not necessarily IFLs in the technical sense, but self-sustaining, climate-regulating ecosystems.

A conspicuous example is the return of old-growth conditions in parts of the eastern United States. The United States does not have much wilderness left, and the eastern part of the country has lost nearly all of its original old-growth forests. Yet forests that were cleared or logged in the past may, if left alone, continue along the long path toward old growth. What is left therefore includes not only the intact landscapes still visible on the map, but also the living systems whose self-recovery is still possible — if we do not interrupt it again.

Reason for Nature

Then one may ask: these natural ecosystems, existing by themselves — why should we protect them?

Some people do not need an answer to this question. They approach it on ethical and philosophical grounds. They believe that these ecosystems have the right to exist, and that this right must be respected.

Others approach the question emotionally and aesthetically: wild nature is beautiful, we love it — let it be.

But apparently there is not enough love or respect for nature among us to stop its destruction. Therefore, we need to broaden the support base for the conservation of wild nature.

I see my own mission as helping to do this on rational grounds. This is not to say that I am not emotional or philosophical in my attitude toward nature. However, emotions and philosophies differ greatly among humans, often dividing us more than contributing positively to our common cause.

The rational argument for preserving wild nature has, however, one non-rational premise: the one connected with the meaning of life.

Professor Victor Gorshkov, the founder of the biotic regulation concept and the scientist with whom I had the privilege to collaborate on the biotic pump concept, published a book in 2000 together with Vadim Gorshkov and me, entitled Biotic Regulation of the Environment: Key Issue of Global Change. It was a book about how life keeps the Earth habitable, written within the tradition of theoretical physics.

And theoretical physicists tend to seek a unified view of the evidence.

So, in this scientific book, there was an index at the end, where one could look up terms such as leaf area index, metabolic rate, greenhouse effect, and so on, each referring to particular pages in the book. And there was also an entry: “Life, meaning,” referring to pages 334–336.

So now, if the meaning of life ever becomes unclear, you know where to look.

The meaning of life is the continuation of life — its persistence.

Once we agree that we want human life to persist into the future — and this is not itself a rational judgment — we can rationally justify preserving wild ecosystems as an indispensable condition for human persistence.

Persistence is therefore the first pillar of the rational case for preserving wild nature.

Complexity

Our next argument is about complexity.

Unfortunately, we have become used to simplifying — and oversimplifying — almost everything: reducing the problem of climate stability to carbon dioxide concentration, or the problem of obesity to Ozempic. Our tactical solutions are often highly sophisticated, but our strategic thinking remains shallow.

This reflects a one-dimensional mode of existence associated with expansion. Humanity has been expanding into the biosphere, destroying living capital. This one-dimensionality makes our strategies primitive: more extraction, more production, more control, more replacement.

Conversely, if we are to live in a steady state, without the progressive transformation of the planet and without the expansion vector, then our strategies for living must become far more sophisticated — and far less obvious. We would need to learn not only how to act, but also how to refrain from acting; not only how to restore, but also how to recognize what must be left alone.

And this would require us to redefine what human progress is, what knowledge is most valuable, and how that knowledge should be judged.

So, if we imagine that we are already those advanced humans of the future — highly skilled in appreciating complexity — the first thing we notice about climate is that it is dynamic, not static. Its state emerges as the outcome of many processes, often acting in opposition to one another.

What would climate be without these dynamics? On an airless, stone-covered planet, surface temperatures would respond far more directly to incoming sunlight and radiative cooling. Earth’s habitable climate is not only a matter of composition; it is also a consequence of circulation, condensation, heat transport, and the living processes coupled to them.

For clouds to form and reflect sunlight, air must rise, cool, and water vapor must condense. Atmospheric motions transport heat upward, while atmospheric and oceanic circulation redistribute heat from the equator toward the poles, shaping where and how this heat escapes to space.

What do I mean by processes acting in opposition to one another? Take atmospheric composition, for example.

The Carbon Cycle

The atmosphere contains nearly one thousand gigatons of carbon. Every year, more than one hundred gigatons of carbon are taken up by the terrestrial biosphere through photosynthesis, while a comparable amount is released back through the respiration and decomposition of countless living beings.

So any serious disruption of these processes could rapidly perturb atmospheric composition — just as we humans have done by suddenly burning organic carbon that had been buried underground for millions of years.

But the functioning biosphere does not simply push this enormous flux in one direction. The opposing processes of synthesis and decomposition are immensely powerful, but they are kept in check. They form not a static balance, but a dynamic one — a balance maintained by life itself.

Unfortunately, the role of the biosphere in the carbon cycle has often been studied within oversimplified frameworks. As a result, despite decades of research, we still do not fully understand how major carbon pools and sinks are changing.

A common premise has been that the carbon value of trees must be expressed through carbon accumulation in their biomass — although, evidently, trees cannot accumulate carbon indefinitely.

Much larger reservoirs of organic carbon than living tree biomass are found in soils and as dissolved organic carbon in the ocean. Yet we still lack robust knowledge of how these immense pools respond to the continuing transformation of the biosphere.

Our eLetter on Bar-On et al. 2025 — bringing the oceanic ecosystem into focus

What we do know is that, so far, on the global scale, land and ocean sinks have responded to anthropogenic carbon emissions in a compensatory way: they have absorbed a major share of our emissions. This does not follow from any simple first principle — except from the biotic regulation concept, which maintains that the biosphere organizes its own homeostasis.

Imagine, instead, that we had found the opposite: that natural ecosystems globally were releasing additional carbon, as degrading lands often do. Our mechanistic understanding would likely explain this a posteriori: the planet warms, soils warm, heterotrophs respire faster, and extra carbon is released.

Indeed, even within current modelling frameworks, different assumptions about the response of soil microbes to warming lead to radically different projections of soil carbon loss.

Modelled response of global soil carbon to warming in conventional soil-carbon models and in a microbial-explicit model. In the dashed green scenario, microbial communities adapt to warming without a decline in microbial growth efficiency, resulting in substantial soil carbon loss. Source: Wieder, Bonan and Allison (2013), Fig. 3b, Global soil carbon projections are improved by modelling microbial processes, Nature Climate Change.

But the remarkable fact is that, so far, the living Earth has been compensating for part of our disturbance. This compensation is not guaranteed. It depends on the continued functioning of ecosystems that are still intact enough to compensate for disturbance rather than amplify it.

This is why complexity matters. When we destroy a natural ecosystem, we are not merely removing a stock of carbon. We are dismantling part of a dynamic living system whose regulatory functions we do not fully understand, cannot reproduce, and may already depend on for our own persistence.

Water Cycle

Another example of tightly coupled opposing processes is the water cycle on land. Plants require water to perform photosynthesis. The opening of stomata needed for carbon dioxide uptake is accompanied by transpiration, during which large amounts of water vapor are released into the atmosphere. Thus, photosynthetic activity is coupled to depletion of local soil water.

In a dry regime, where vegetation is sparse and the atmosphere remains relatively dry, additional transpiration may exceed any associated increase in precipitation. Vegetation then appears to reduce water availability: more greenness means less runoff.

But this is not the only possible regime. As vegetation develops and transpiration moistens the atmosphere, precipitation may begin to respond more strongly. In a wet forest regime, increased transpiration can be coupled to increased moisture convergence and rainfall. More vegetation can then mean not less, but more available water.

Thus, the same process — transpiration — can appear either as a loss of water or as part of a mechanism sustaining abundant rainfall, depending on the state of the ecosystem and atmosphere. A disturbed ecosystem in a dry regime cannot reveal the full hydrological function of an intact wet forest. [see “Ecosystem Recovery, Atmospheric Dynamics, and the Water Cycle”]

Power

The third argument — historically, the first — comes from Vladimir Vernadsky: seen against the background of geochemical processes, and even of anthropogenic environmental impacts, the processes of the biosphere are immensely powerful.

Evidence of the greater resilience of intact ecosystems brings Persistence, Complexity, and Power together in one observation. It is a very important line of evidence in favor of biotic regulation. When an ecosystem that has maintained itself over immense periods of time is arbitrarily modified, its function may rapidly deteriorate. This is what we should expect when we intervene in something whose functioning we do not understand in full — precisely because its complexity exceeds ours.

Data from Bowman et al. 2026 illustrating that young tree stands that form after logging are more susceptible to fires than mature forests.

The opposite of resilience is fragility. One way to see this fragility is through turnover times: by comparing the size of an environmental reservoir with the magnitude of the fluxes running through it. When the fluxes are large relative to the reservoir, a loss of regulation can change the state of the system very rapidly.

For atmospheric carbon, the turnover time with respect to biospheric exchange is about ten years. For modern groundwater stores on land, the turnover time with respect to global river runoff is also short — about six years.

These are almost instantaneous timescales compared with the millions of years over which ecosystems have persisted. The contrast is sobering: variables that make the Earth habitable can change very quickly, while the living complexity that keeps them within viable bounds has taken immense time to evolve and cannot be rebuilt at will.

Therefore, the rational case for preserving wild nature, as I see it, rests on three pillars:

Persistence — Complexity — Power

By persistence, I mean the continuation of life, including human life, into the future.

By complexity, I mean that conditions suitable for life are not maintained by one variable, one mechanism, or one technological fix. They emerge from the interplay of many dynamic processes — physical, chemical, and biological — often acting in opposite directions.

And by power, I mean that life is one of the strongest forces shaping the Earth system, capable not only of transforming the environment, but also of maintaining it in a state suitable for life.

To keep such powerful, complex, multidirectional processes within the narrow range compatible with life requires complexity of the same order. Natural ecosystems possess this complexity, but we will never know it in full detail. When we disturb this complexity, we impair function. And when we impair function on a large scale, we risk destabilizing climate.

Therefore, the evidence for the importance of natural ecosystems does not come primarily from how they affect one parameter that currently seems most important to us — for example, carbon stored in tree biomass. It comes from a deeper observation: the equilibrium that sustains life is dynamic, fragile, and maintained by life itself.

The more we understand the Earth system, the less plausible it becomes that we can dismantle its living complexity and still keep its stabilizing function.

Related reading:

Their study adds an important radiative dimension to a phenomenon that has been discussed in the Amazon literature for some time: shallow clouds can occur more frequently over cleared land than over nearby forest. Using satellite observations for 2003–2022, Dror and Feingold demonstrate that this enhancement of low-level cloudiness over deforested areas substantially strengthens the local top-of-atmosphere cooling signal relative to nearby stable forest.

This is a valuable result. But it demands especially careful interpretation.

The reason for our concern can already be seen in the accompanying commentary by Gunnar Myhre, published in the same issue of Science. Its title is Clouds moderate Amazon deforestation’s climate effect. Its subtitle reads: “An unexpected increase in cloud cover partially reduces warming caused by carbon dioxide release.” The commentary ultimately affirms the importance of maintaining and restoring Amazon forest cover. Yet an important qualification in Dror and Feingold’s paper is absent from it: they note that low-level cloudiness declined across the Amazon basin on average. As discussed below, even this mean decline does not reveal the regional structure of cloud loss.

Thus, a result derived from comparing deforested pixels with nearby stable forest has already entered discussion as an effect that partially reduces the warming caused by deforestation.

Here the issue of scale becomes critical.

A cleared patch can indeed be cloudier than the forest immediately beside it. From space, it may look locally cooler because it reflects more sunlight. But that does not mean that ongoing deforestation is making the Amazon as a whole cloudier, cooler, wetter or more resilient.

The local signal may arise because a clearing, embedded within a still substantially forested landscape, redistributes convection and clouds at the expense of neighbouring forest. Meanwhile, the more heavily disturbed regional sector may be drying, losing low-level clouds and becoming less able to sustain rainfall.

In short, the issue is not whether the local cooling signal is real. The issue is that it risks being interpreted as a climatic benefit of forest loss — without first asking the essential questions:

Relative to what — and at what scale?

Our eLetter, also available as an ESS Open Archive preprint, addresses this distinction. Below, I reproduce it in full. Afterwards, I provide additional context: how earlier research on local cloud patterns had already raised the question of spatial scale; what independent evidence suggests about the larger regional trajectory; and why the climatic function of an intact forest cannot be assessed clearing by clearing.

Our eLetter to Science

Stealing Forest Clouds?

Anastassia M. Makarieva, Andrei V. Nefiodov, Antonio Donato Nobre, Luz Adriana Cuartas, Mara Baudena, Germán Poveda, Juan Fernando Salazar

Affiliations:
Biotic Pump Greening Group Institute, São José dos Campos, Brazil;
Theoretical Physics Division, Petersburg Nuclear Physics Institute of NRC “Kurchatov Institute,” Gatchina, Russia;
National Center for Monitoring and Early Warning of Natural Disasters (CEMADEN), São José dos Campos, São Paulo, Brazil;
Institute of Atmospheric Sciences and Climate, National Research Council, Turin, Italy;
Department of Geosciences and Environment, Universidad Nacional de Colombia, Medellín, Colombia;
Escuela Ambiental, Facultad de Ingeniería, Universidad de Antioquia, Medellín, Colombia.

Dror and Feingold use 2003–2022 satellite observations to estimate the local radiative response to Amazon forest loss (1). They report that deforested pixels have more low-level clouds and lower cloud tops than nearby stable forests, increasing reflected shortwave radiation and yielding a local all-sky biophysical cooling signal. This result is important, but its interpretation depends on scale.

Their comparison is between cleared pixels and forests within 10–50 km. This is the scale at which deforestation can redistribute convection, clouds, and rainfall rather than generate a net increase.

Forest–nonforest transitions affect rainfall locally (2). Forest loss can increase rainfall at 20–80 km but decrease at about 200 km (3), while another analysis found wet-season enhancement locally but reductions beyond about 60 km (4). Clearing creates gradients in temperature that can favor clouds over open land while suppressing them over adjacent forest through a breeze-like circulation (5).

In this sense, deforested areas may be “stealing” forest clouds: reorganizing cloudiness within a drying atmospheric system rather than creating additional clouds. This is consistent with Dror et al. (6), who show that shallow green cumulus in the Amazon is associated with positive relative-humidity anomalies. This would suggest reduced cloud formation under basin-wide drying. Dror and Feingold note a basin-wide decline in low-level cloudiness that was less pronounced over cleared land at their comparison scale (1). At larger scales, however, the relative pattern appears to reverse: many deforestation hotspots are located in regions of declining low-cloud cover (Fig. 1), consistent with the observed dipole of increased solar-radiation absorption over the more deforested southeastern Amazon and decreased absorption over the least deforested northwestern Amazon (10).

The importance of scale becomes even greater when these findings are projected to increasing deforestation. Understanding deforestation’s climate impact requires assessing local radiative effects together with atmospheric dynamics.

Figure 1. Low-level cloud trends from Ceppi et al. (2026), with Amazon deforestation hotspots from Mataveli et al. (2022) and Finer et al. (2025) shown as black dots.

References and Notes

1. T. Dror, G. Feingold, Amazon forest loss: An all-sky biophysical top-of-atmosphere cooling feedback. Science 392, 429–432 (2026).

2. R. Knox, G. Bisht, J. Wang, R. Bras, Precipitation variability over the forest-to-nonforest transition in southwestern Amazonia. Journal of Climate 24, 2368–2377 (2011).

3. A. T. Leite-Filho, B. S. Soares-Filho, J. L. Davis, G. M. Abrahão, J. Börner, Deforestation reduces rainfall and agricultural revenues in the Brazilian Amazon. Nature Communications 12, 2591 (2021).

4. Y. Qin, D. Wang, A. D. Ziegler, B. Fu, Z. Zeng, Impact of Amazonian deforestation on precipitation reverses between seasons. Nature 639, 102–108 (2025).

5. J. Wang, F. J. F. Chagnon, E. R. Williams, A. K. Betts, N. O. Renno, L. A. T. Machado, G. Bisht, R. Knox, R. L. Bras, Impact of deforestation in the Amazon basin on cloud climatology. Proceedings of the National Academy of Sciences 106, 3670–3674 (2009).

6. T. Dror, V. Silverman, O. Altaratz, M. D. Chekroun, I. Koren, Uncovering the large-scale meteorology that drives continental, shallow, green cumulus through supervised classification. Geophysical Research Letters 49, e2021GL096684 (2022).

7. P. Ceppi, S. Wilson Kemsley, H. Andersen, T. Andrews, R. J. Kramer, P. Nowack, C. J. Wall, M. D. Zelinka, Emerging low-cloud feedback and adjustment in global satellite observations. Atmospheric Chemistry and Physics 26, 4153–4171 (2026).

8. G. Mataveli, G. de Oliveira, M. E. D. Chaves, R. Dalagnol, F. H. Wagner, A. H. S. Ipia, C. H. L. Silva-Junior, L. E. O. C. Aragão, Science-based planning can support law enforcement actions to curb deforestation in the Brazilian Amazon. Conservation Letters 15, e12908 (2022).

9. M. Finer, A. Ariñez, N. Mamani, M. Cohen, A. Santana, Amazon Deforestation & Fire Hotspots 2024. Monitoring of the Andes Amazon Program 229 (2025).

10. J. Cui, S. Piao, C. Huntingford, T. Wang, D. V. Spracklen, Historical deforestation drives strong rainfall decline across the southern Amazon basin. Nature Communications 17, 1642 (2026).

Additional context

Earlier research on local cloud patterns and the question of scale

The tendency for shallow clouds to occur more frequently over cleared Amazon land than over adjacent forest has been examined in earlier research. In 2009, Jingfeng Wang and colleagues showed that shallow clouds preferentially occurred over deforested surfaces, whereas the less frequent deep clouds tended to favour forested surfaces. They related this local pattern to atmospheric circulations generated by contrasts between forest and clearing: where surfaces with different properties occur side by side, rising air and cloud formation can be redistributed across the landscape.

Importantly, Wang and colleagues also recognised that this local response raised a question about progressive deforestation. A clearing embedded within extensive forest is not physically equivalent to a landscape where forest loss has expanded over large areas. As the landscape becomes more uniform, the local contrast responsible for enhanced shallow cloud formation over clearings may weaken or disappear.

They wrote:

“There must be a limit to the length scale of land cover heterogeneity above which the lifting mechanism is lost and the enhancement of shallow clouds over deforested areas will disappear.”

A local radiative contrast between clearing and neighbouring forest cannot automatically be extrapolated to the climatic effect of continuing deforestation across the Amazon.

From a basin-wide mean to the regional pattern

Dror and Feingold note that low-level cloudiness has declined across the Amazon basin on average. Yet an average decline does not identify its spatial structure. It could reflect similar losses throughout the basin, or it could be dominated by losses in more heavily disturbed regions while less disturbed regions remain comparatively stable or show increasing cloudiness.

Figure 1 above points to the latter possibility. Many major deforestation hotspots are situated in regions of declining low-cloud cover, particularly in the more deforested southern and eastern Amazon. Toward the less disturbed northwest, low-cloud trends are markedly different.

This regional pattern does not contradict Dror and Feingold’s local comparison. At distances of tens of kilometres, a clearing may be cloudier than nearby stable forest. At the scale of broad Amazon regions, however, extensive forest loss occurs within landscapes showing declining low-cloud cover, while less disturbed regions show markedly different cloud trends.

This distinction is central to the phrase “stealing forest clouds.” A deforested patch may locally attract or retain more shallow cloud relative to its immediate forest neighbour, while, at broader regional scales, major deforestation hotspots occur within regions of diminished cloud cover and weakened cloud shielding.

The Amazon dipole: contrasting trends in cloud shielding

A complementary indication of this regional structure comes from the recent study by Jiangpeng Cui and colleagues, Historical deforestation drives strong rainfall decline across the southern Amazon basin. Their analysis shows greater sunlight reaching the surface in the more deforested southern and eastern Amazon, but decreasing surface sunlight in the less deforested northwest.

Forest loss and sunlight reaching the Amazon surface. In the more heavily deforested southern and eastern Amazon, forest cover declined while more downward shortwave radiation reached the surface. In the less deforested northwestern Amazon, downward surface shortwave radiation tended to decrease. Source: Cui et al. (2026), Nature Communications.

The variable shown here is incoming sunlight at the surface, not cloud cover directly. Nevertheless, the spatial contrast is consistent with weakening cloud shielding in the more deforested southern and eastern Amazon and increasing cloud shielding in the less deforested northwest.

Thus, a clearing may be locally cloudier than nearby forest, while the broader regional pattern associates greater forest disturbance with declining cloud protection.

What happens as deforestation progresses?

A clearing surrounded by extensive forest can generate a local atmospheric contrast. But what happens when clearings expand, the forest becomes fragmented, and the landscape becomes increasingly uniform?

There is a memorable illustration of this question from Australia. In 2002, Tom Lyons published a paper with the direct and beautiful title, Clouds prefer native vegetation. In southwest Western Australia, where large areas of native vegetation had been replaced by agriculture, clouds could be seen forming preferentially over native vegetation while cleared land remained largely cloud-free.

A friend recently sent me a photograph illustrating the same striking pattern.

Clouds over vegetation beside cleared land in eastern Australia, May 2026. This contemporary photograph visually echoes the phenomenon discussed by Tom Lyons in Clouds prefer native vegetation. Image shared by a good friend and reproduced with permission.

This photograph helps us see why the response of one clearing embedded within forest cannot simply be extrapolated to a progressively deforested landscape.

Within a forest–clearing mosaic, open land may locally attract shallow clouds because it contrasts with the moist forest around it. But after more extensive removal of native vegetation, the landscape may lose the moisture supply and atmospheric organisation needed to sustain clouds more broadly.

A cloudier clearing can therefore be a feature of a still-heterogeneous landscape — one that remains dependent on the forest surrounding it.

Relative effects and actual trajectories

In my recent mini-series, China at an Ecohydrological Crossroads, I discussed a related interpretive problem.

In the China case, a reported decline in water availability associated with re-greening was not an observed regional decline. It was a reconstructed relative effect: an estimate of how vegetation change altered water availability compared with a hypothetical trajectory without that change. Meanwhile, the directly reported ERA5 trend showed slightly increasing water availability in China during the studied period.

The Amazon-cloud question is different in its processes and observations. Yet the same distinction matters here: a relative local effect should not be mistaken for the actual trajectory of the larger system.

A deforested Amazon patch may have more low clouds than nearby forest. This does not establish that progressive deforestation is making the Amazon cloudier.

A cleared patch may exhibit a local cooling signal relative to neighbouring forest. This does not establish that deforestation offsets warming.

The new Science paper shows that local cloud changes are an important part of the radiative response to forest loss. What this local signal means for a progressively deforested Amazon is a different question.

A clearing may brighten and become locally cloudier. But the clouds above it may, in part, depend on the forest system that its expansion would help to erode.

Let us work to stop deforestation in the Amazon. When asked by when this must be done, Antonio Nobre has a simple answer: “By yesterday.”

Related reading [another eLetter about Forests and Clouds]:

When, in the 18th century, we learned to use steam to produce motion, we called it the Industrial Revolution. And with good reason. James Watt’s improved steam engine ushered in an era of extraordinary technological innovation and sweeping social and economic change. The mass production of goods, the great rural exodus, and the rise of economic and political systems that still shape our world all trace their roots to that pivotal moment.

Little did we know that steam would one day stand at the center of another revolution. This time, however, it is not the steam that drives pistons, but the vapor that drives winds and weaves clouds. Not the steam that comes from burning coal, but the vapor lifted by forests, gracefully carrying heat from Earth’s surface upward, releasing it into space, delivering rain far inland, and maintaining the planetary conditions for life.

Unlike the first, the “Second Steam Power Revolution” relies on a mechanism that extracts nothing, generates no waste, and runs on sunlight rather than fire. If the first revolution led us to agglomerate in urban centers and fueled the illusion that we could conquer nature’s limits (a popular notion of its time), the second invites us to reconnect with nature and realign human systems with the living engines that sustain the biosphere, which in turn creates a hospitable planet. It calls us to recognize our role as conscious agents within the planetary water cycle, restoring rather than disrupting its elaborate flow. It is around the scientific exploration and dissemination of these principles and practices that the Biotic Pump Greening Group was formed.

Scientific Intuition and the Seeds of a New Climate Paradigm

In the mid-70s, in the Russian taiga, physicist Victor Gorshkov gazed at the Yenisei River and wondered, “If all this water flows to the sea, there must be a mechanism that brings an equivalent volume back to the continent.” In the early 2000s and thousands of kilometers west, Earth scientist Antonio Nobre looked out over the Amazon rainforest and asked, “How, despite known global cataclysms, did this magnificent biome sustain abundant rainfall over millions of years, without interruption? Is it just a passive hitchhiker of a favorable environment or a sitting duck for climate change?” Questions like these are the lifeblood of science. They arise from the suspicion that something essential is being overlooked, that there is still a principle to uncover, a pattern to explain.

When Antonio Nobre - a rainforest veteran and a longtime enthusiast of the Gaia hypothesis - first read the book Biotic Regulation of the Environment (2000) by Victor Gorshkov and Anastassia Makarieva, the intellectual connection was immediate. At the time, he was deeply immersed in ecoclimate data from the Large-Scale Biosphere-Atmosphere Experiment in Amazonia (LBA), which was propelling him toward a startling conjecture: natural forests might not merely submit to the whims of climate; they appeared to actively concoct the environment for their own comfort and benefit. This idea matched squarely with Gorshkov and Makarieva’s Biotic Regulation of the Environment Theory.

Their enlightened explanation of how ecosystems manipulate environmental flows struck him profoundly. For Nobre, it provided an elegant, first-principles foundation for the earlier insights of Gaia, much as Kepler and Newton had for the heliocentric model of Copernicus. Awed by the Russian theory, he reached out to the physicists in September 2004. Eager to test his conjectures, he challenged them to apply their grand theory to the Amazonian mystery: “prove physically how the rainforest keeps itself wet.”

This call to action from Amazonia sparked a new phase of their research. The ensuing collaboration - fusing Nobre’s empirical knowledge with the Russians’ theoretical prowess - led to Gorshkov and Makarieva’s reference work in 2007, which crystallized these ideas into the “Biotic Pump Theory.” Their productive and long-lasting partnership grew to include other key collaborators, such as the theoretical physicist Andrei Nefiodov, the hydro-meteorologist Adriana Cuartas, and the climate modeler Paulo Nobre, among others in several fields of knowledge. Ultimately, Antonio’s invitation wasn’t just about testing a theory; it was about sharing and articulating knowledge across disciplines and continents.

How Forests Move the Sky

The Biotic Pump Theory describes a physical and ecological mechanism by which forests attract moisture-laden air and secure their own water supply. Through photosynthesis and transpiration, forests release vast amounts of water vapor into the atmosphere. When this vapor condenses into clouds, it releases latent energy, causing a drop in local air pressure. As clouds turn into rain, this pressure difference acts like a pump, propagating downward and laterally, pulling moist air from the oceans toward the interior of continents. Forests also emit a variety of organic gases and particulates, such as terpenes, isoprenes, pollen, spores and others that act as cloud condensation seeds, helping raindrops form and enhancing precipitation. These mechanisms drive winds, deliver rainfall far inland, and help regulate global temperature by carrying heat upward, where it can dissipate into space. It also explains why declining tree cover threatens water security for hundreds of millions of people worldwide. In short, the Biotic Pump Theory shows that forests are dynamic engines of the hydrological cycle and key stabilizers of the planet’s climate, not just passive carbon sinks.

A Climate Theory Under Pressure

New ideas in science rarely gain acceptance overnight, and that’s precisely what protects their credibility. Every hypothesis must endure rigorous scrutiny, exposure to contradictions, and countless rounds of questioning. This is the nature of scientific progress, and the proponents of the Biotic Pump have embraced it fully, prepared to engage with critique and debate the theory in every arena.

The journey, however, was anything but easy. Their landmark article, Where Do Winds Come From?, faced a grueling public review process that lasted two and a half years before finally being published. Such resistance is not unusual for disruptive ideas, but in this case there was an aggravating factor. The principle at the heart of the Biotic Pump Theory unleashed a veritable earthquake in mainstream meteorology by demonstrating a long-overlooked physical factor: water vapor condensation as the main driving force in tropospheric circulation. In 2010, during its open peer-review phase in Atmospheric Chemistry and Physics Discussions, the paper ignited an unprecedented debate that spilled beyond the journal into various digital platforms, gathering more than 1,500 comments in a single online thread. Nearly all were addressed by Anastassia Makarieva, whose ability to turn intellectual challenge into energy is remarkable. This episode later became the subject of a sociological study on how digital platforms are transforming scientific communication by expanding the reach of ideas, accelerating feedback, and fostering more transparent and interactive exchanges. It highlighted the power of open peer review and online forums to serve as a new kind of scientific agora: a public square where complex and novel concepts can be debated in full view of the global community.

However, at first, the openness of the platform alone was not enough to prompt meaningful engagement from defenders of conventional climate models. It took repeated public invitations to revisit the arguments and analyze them rigorously. The persistence of the Biotic Pump authors - thoroughly documented in the open-review record - made it clear that the conversation would not simply fade away. Their insistence on dialogue underscored a deeper tension in the field: a reluctance to confront a framework that questioned the foundations of established models.

At the heart of the controversy lies a fundamental point: in conventional climate models, the work performed by the atmospheric heat engine is formulated via tuning parameters - something adjusted to observations but not derived from first principles. As a result, while these models register condensation and precipitation, they fail to capture the ability of these processes to physically influence atmospheric circulation and generate winds.

The Biotic Pump, by contrast, proposes that, if condensation is properly accounted for, it can not only refine our understanding of wind and rainfall but also explain the persistent gaps between projected and observed climate: from the abrupt onset of monsoons to the mechanisms that fuel the destructive power of cyclones, and even the extreme temperature peaks since 2023, which exceeded the most pessimistic projections.

This is no ordinary academic debate. It touches one of the most politically and economically sensitive areas of science today: the emphasis on the role of carbon-containing greenhouse gases, particularly CO_2​, as the primary driver of climate change. A perspective that adds forests and atmospheric vapor flows to the equation inevitably challenges the foundations of this “carbon-centric” narrative, along with the global markets, funding structures, and careers that have been built around it.

Initial efforts to sideline the Biotic Pump were unmistakable. But over time, that strategy failed. Today, dozens of peer-reviewed articles exploring the Biotic Pump have been published in respected scientific journals. Each new contribution has broadened the conversation, and the vigor of the exchanges that follow speaks to how consequential the debate has become.

Scientific breakthroughs often depend on moments when old assumptions give way to new ways of thinking. These moments do not emerge in isolation. They require spaces for open dialogue, conceptual flexibility, and cross-disciplinary thinking. And because these shifts ripple far beyond academia, engaging with broader society is just as important as internal consensus.

To support this transition, we may need to develop new languages. Ones that can describe the intricate relationships between forests, water, atmosphere, and life. What’s certain is that we need to share: share ideas, share evidence, share lived experiences. Because interconnection is not just a property of ecosystems. It’s also the foundation of how knowledge evolves, whether you’re looking up to the atmosphere or kneeling close to the soil with your hands in it.

Restoring Climate from the Soil Up

In 2015, a new thread was woven into the fabric of the Biotic Pump Greening Group. Once again, it was Antonio Nobre who acted as the seamster, just as he had in 2004, when he invited Victor Gorshkov and Anastassia Makarieva to study the Amazon. This time, however, what caught his attention was not a theoretical model, but a practical approach to land management: Syntropic Farming - a regenerative agroforestry system developed by Swiss farmer and geneticist Ernst Götsch. This approach seeks not only to recreate the structure of forests but also their functional complexity.

Through ongoing exchanges with Felipe Pasini and Dayana Andrade, experienced practitioners and long-standing collaborators of Ernst Götsch, the group gained field insights and practical frameworks for translating Biotic Pump physics into land-based strategies. In 2019, Felipe and Dayana officially joined the group, anchoring a deeper alliance between cutting-edge ecological science and restoration practices.

This integration was critical because activating the Biotic Pump is not simply a matter of increasing green cover. Reforestation without ecological coherence - especially the widespread use of fast-growing monocultures - has often led to low survival rates, poor ecosystem function, and, in some cases, even greater disruption of local water cycles.

Syntropic systems, by contrast, are based on ecological principles of stratification (organization of species into functional layers) and natural succession (temporal progression of plant communities over time). This vertical complexity creates multiple microclimates and pressure differentials that enhance air circulation, while intentional temporal dynamics accelerate regeneration toward mature systems capable of properly activating the Biotic Pump.

Farming that integrates nature's complexity: this footage documents 3 years and 7 months of transformation in southern Italy. From depleted land to a stratified, successional syntropic agroforestry system. A deliberate act of recovery through agriculture, from the soil up.

This integrated perspective now informs the group’s projects in diverse and challenging environments, from arid landscapes in Saudi Arabia to climate-stressed vineyards in France. By combining climate diagnostics, landscape hydrology, and syntropic design, the group develops land-use strategies that restore ecological functions, whether through large-scale regreening or by adapting productive systems to enhance climate resilience.

While the Biotic Pump theory provides the scientific foundation for preserving intact forests, syntropic agriculture complements this imperative with a practical blueprint for restoring degraded lands through farming. By making reforestation productive, it eases the pressure to convert natural forests into farmland and reframes restoration not as a moral imposition or economic sacrifice, but as a regenerative strategy that is both viable and desirable.

The Intelligence That Builds Upward

Watch a forest emerge from abandoned farmland, and you witness something that defies our industrial logic entirely. Where, over time, our machines inevitably wear down, break apart, and return to rust, living systems grow more intricate, more capable, more fertile with each passing season. This is the profound difference between entropy and syntropy - between systems that disperse energy and those that organize it into ever-greater complexity.

Industrial steam engines exemplify entropy in action: fuel burns, heat disperses, metal fatigues, and each cycle brings wear. The second law of thermodynamics governs this realm with iron certainty - energy always flows from organized to disorganized states, from useful to wasteful forms.

But step into an old-growth forest, and you encounter a different, fascinating physics. Here, diffuse sunlight becomes living wood. Atmospheric chaos becomes orchestrated rainfall. Simple soil microbiomes become vast networks that communicate across miles of root systems. This is syntropy: a concept, first demonstrated by the Italian mathematician Luigi Fantappiè in1944 and later explored (as “negative entropy”) by scientists like Austrian-Irish theoretical physicist Erwin Schrödinger and by Hungarian physiologist Szent-Györgyi to describe how living systems sustain and increase their internal order.

The forest operates like a factory where the machinery doesn’t just maintain itself - it continuously redesigns itself to become more efficient, more resilient, more interconnected. A mature tropical forest can move more vaporous water across a continent than the Amazon River moves to the sea, yet it does so while simultaneously cooling the planet, generating its own rainfall, and supporting millions of species in elegant collaboration.

This is the result of self-organizing processes, where individual components dissolve their boundaries and function as interdependent parts of a larger, co-evolved system. Each tree is both itself and part of something more. Each root network is both autonomous and entangled. Forests are living engines, operating with the precision of Swiss clockwork, but with the accumulated wisdom of millions of years of evolution.

Our current crises - climate breakdown, social fragmentation, ecological collapse - are symptoms of trying to solve 21st-century problems with 19th-century thinking. We’re still operating like black-soot-spewing steam engines in a world that demands the green brilliance of forest intelligence.

Toward a Regenerative Culture

In 2024, the Biotic Pump Greening Group further advanced its vision by co-organizing the international conference Embracing Nature’s Complexity, held in Munich.

Far from a traditional academic event, it brought together scientists, farmers, policymakers, entrepreneurs, poets, communicators, and restoration practitioners from around the world. The goal: to elevate nature preservation with a strong scientific foundation, while bridging the disciplinary divides that have long hindered a full appreciation of ecosystems’ role in climate regulation and human well-being.

Currently, the group continues its work through an integrated and decentralized structure, spanning theoretical research, applied science across biomes, and support for large-scale ecological design and policy. Its members also contribute to intergovernmental programs, civil society initiatives, and educational institutions, promoting both eco-literacy and science-informed decision-making. Beyond scientific publications, the group embraces storytelling, art, and public communication as essential tools for translating data into shared meaning, helping to catalyze a cultural shift toward more conscious and collaborative ways of living on Earth. These diverse fronts operate across regions and disciplines, yet remain unified by a common aim: to protect and restore the living systems that make the planet habitable and to reweave the relationship between climate, culture, and care.

If mastering the steam engine required understanding pressure and combustion, engaging with the biotic steam engine demands something else entirely: ecological empathy. This shift redefines humanity’s role, not as external managers of nature nor even as benevolent stewards acting upon it, but as conscious participants in a planetary body, contributing our creativity and intelligence to life’s unfolding complexity.

This is the revolution already underway. And it begins, like all life does: growing by sharing.

Dayana Andrade is a journalist and syntropic farming practitioner. She is a member of the Biotic Pump Greening Group, where the connections between forest, water, and climate that Anastassia's work illuminates meet the hands-on practice of syntropic farming. With a Ph.D. in Environmental Sciences, she co-authored the book “Vida em Sintropia” with Felipe Pasini (available in PT, IT and FR). If this piece sparked your curiosity, follow their journey at “Life in Syntropy”.

Life in Syntropy

Here is where Dayana Andrade and Felipe Pasini publish in English about syntropic agriculture as a lived practice, a design approach, and a way of understanding regeneration.

By Dayana Andrade

Related reading:

How does a new idea come into your head? I honestly do not know, but perhaps one of the ways is to reach calmness. In this calmness, you begin to see the invisible surface of the Universe, which sometimes has small wrinkles. These wrinkles are pre-ideas: they appear and disappear, but if you are attentive, you may see a pattern and catch one of them mentally, capture it into being — and then, voilà, you have a new idea. Which can also be wrong — meaning that it belonged to a different Universe.

The idea for this paper, new then but accomplished now, came almost exactly one year ago, when we were in Siberia, in a small cabin in the taiga, already one week disconnected from civilization. The brain was still running at full force in an analytical mode, but calmness was already setting in — and then it came.

Now, over the course of this one year, it has matured into a full-fledged work, which we were able to submit two days before we depart for Siberia again, to disappear once more into the green. It feels so bizarre to be free to go, having done what you felt you had to do. Fais ce que dois, advienne que pourra.

So this post shares a mixture of emotions and scientific content from the new paper, which you can find on arXiv here, with the codes for all calculations available at Zenodo:

http://arxiv.org/abs/2605.23875

https://doi.org/10.5281/zenodo.20371682

I am posting this from the airport. The next four posts will come as scheduled posts, as I will be offline until the second week of July.

The Last Day of Pompeii

The Last Day of Pompeii by Karl Bryullov

This is a very large painting in the State Russian Museum in St. Petersburg, where I live. It has a bench nearby, so when we, as schoolchildren, were guided through the museum, one could always rest on this bench and at the same time contemplate the tragedy.

Meanwhile, the guide would explain that the painting tells many stories at once, stories of different people and their small groups. There are sons saving their elderly father; a wounded mother parting with her son; a young family trying to escape with a child. Together, these separate stories create the joint impression of a great drama — which I did not quite experience as tragic when I was a small girl, because the negativity and angst of the painting were softened by the opportunity to rest on the bench.

But I loved the colors.

Our scientific paper, “Atmosphere as a Steam Engine,” is similar in that sense: it weaves together several stories that, especially if you know the context, are quite dramatic. Since our restless minds sometimes have difficulty synthesizing things, we created a sort of painting in the Discussion section, bringing all these stories together for a comprehensive evaluation.

Here it is — let me share three of those stories with you. Please allow me a little drama in the telling: the dry scientific prose is in the arXiv version.

Abstract of “Atmosphere as a steam engine”

Earth’s atmosphere operates a steam cycle in which water vapor evaporates from the surface, expands, condenses in colder air, and returns as precipitation. The Clausius–Clapeyron law relates the incremental expansion work of saturated water vapor to latent heat converted at a Carnot efficiency corresponding to the temperature difference between evaporation and condensation. We generalize this relation to an atmospheric column in which condensation occurs over a range of heights and derive the expansion work per mole of precipitated water. This includes the gravitational work associated with lifting moist air to the mean condensation height, the expansion work generated by condensation, and a correction for incomplete condensation.

Using GPCP v3.3 precipitation and observational constraints on condensation height, we estimate the global steam-engine power as W_v = 4.4 ± 0.9 W m⁻². This is close to an independent estimate of total atmospheric power, W = W_P + W_K ≃ 4.3 ± 0.6 W m⁻², obtained from the gravitational power of precipitation and kinetic energy generation by horizontal pressure gradients diagnosed from MERRA-2. Kinetic energy generation is W_K ≃ 3.2 ± 0.3 W m⁻², of which at least two thirds is generated in the lower atmosphere. The smaller upper-atmospheric contribution is dominated by temperature-related pressure gradients and is comparable to Lorenz available potential energy generation.

We argue that the agreement between steam-engine and atmospheric power is physically linked to condensation and precipitation fallout. By removing water from the atmospheric gas phase and enabling column-mass redistribution, precipitation can maintain surface pressure gradients that drive cross-isobaric flow in the frictional lower atmosphere. The steam-engine framework thus provides a thermodynamic basis for condensation-induced atmospheric dynamics and identifies a major lower-atmospheric power pathway associated with water phase transitions.

First story: A Major Gain in Credibility for Biotic Pump Physics

The biotic pump came into being as a physical concept based on the following consideration: the distribution of water vapor in the atmosphere is strongly compressed relative to that of other gases. This non-equilibrium pressure distribution, caused by water vapor disappearing from the gas phase, allows air to expand and perform work at a rate proportional to condensation. Thus, wind power is proportional to condensation rate.

This formula expresses local kinetic energy generation, σ_CIAD, in the framework of condensation-induced atmospheric dynamics (CIAD, the physical basis of the biotic pump). Here, w is vertical velocity, p_v is water vapor partial pressure, p is air pressure, z is altitude, and γ = p_v/p reflects the relative water vapor content of air. The formula says that kinetic energy is generated in proportion to the decline in this relative water vapor content in rising air as condensation proceeds.

However, this idea, and the corresponding formulations, were kind of an orphan in the community of meteorological truths. It seemingly did not have any connections, yet claimed big things — predicting the magnitude of the atmospheric power of Earth as well as hurricane power. In a way, it could be compared to Kikuchiyo, the “incorrect” samurai from the Seven Samurai by Akira Kurosawa.

Kikuchiyo was not a samurai by birth. He arrived with a false genealogy, noisy manners and an impossible sword.

Orphans do not have the family protection and external attacks are more difficult to handle for them than for others.

For the biotic pump concept, a major line of criticism has always been that the effect is “small.” The controversy here is that the main formulation of the biotic pump correctly predicts the observed magnitude of wind power, so its effect is demonstrably not small. But since the origins of this formulation remained unclear, one could argue that it simply could not be so — while there was nothing carved in stone that ruled out a significant role for atmospheric water vapor pressure differences.

For example, Axel Kleidon wrote the following, with my emphasis:

While it is well known and established that water vapor pressure differences can perform physical work and thus generate motion, the conditions that are associated with this are very different to the Earth’s atmosphere. One practical example of work done by water vapor is the steam engine. Yet, to perform work, the operating temperature and vapor pressure differences of steam engines are substantial. They operate with temperatures above the boiling point of water, for which the saturation vapor pressure is greater than the mean sea level pressure. Such water vapor pressure differences (and temperature differences) are much greater than what is observed anywhere in the Earth’s atmosphere, which at best amount to 3% of the air pressure. Because water vapor pressure differences on Earth are much smaller, the effect on buoyancy can be neglected. Hence, the BP hypothesis is, in principle, not unphysical, but simply focuses on an irrelevant effect and does not explain why convective motion takes place.

That is to say, the criticism did not address how the conclusion about the significant role of water vapor pressure differences had been reached — because this remained obscure. Rather, it argued that the effect must be small because atmospheric water vapor pressure differences are small. There was no common thermodynamic ground on which this dispute could be settled.

And such a battle was difficult for either side to win. As Fred Pearce wrote in Science in 2020:

Since then, there has been neither validation nor disproof, but largely a standoff.

In this paper, we explicitly consider the steam-engine power of the terrestrial atmosphere. The physical picture is relatively straightforward: water vapor evaporates, rises, expands, condenses and precipitates. But the calculation requires accounting for different heights and temperatures, since droplets form at different heights.

After all, why should a huge temperature difference be needed to produce significant power? Significant power can be generated even at a small temperature difference, provided that there is a lot of rain. This is what happens on Earth.

By the way, a pressure difference amounting to 3% of atmospheric pressure — about 30 hPa — corresponds energetically to a wind velocity exceeding 50 m s⁻¹.

During these derivations, we showed that the CIAD formulation represents a part of the steam-engine work: the part related to water vapor expansion caused by condensation. The total work of Earth’s atmospheric steam engine

includes:

[a] the gravitational work associated with lifting moist air to the mean condensation height;
[b] the expansion work generated by condensation;
[c] a correction for incomplete condensation in rising air.

We showed that CIAD represents contribution [b], with contribution [c] assumed to be zero — corresponding to complete condensation.

In the measured and delicate language of a scientific paper, the summary of this story reads as follows:

…since 2007, condensation-induced atmospheric dynamics (CIAD) has suggested that condensation and precipitation contribute substantially to atmospheric power by generating surface pressure gradients. These ideas have given rise to extensive discussion. In particular, the relationship between condensation rate and power generation, while yielding meaningful predictions across diverse meteorological contexts, has remained largely heuristic. The steam-engine formulation developed here provides a thermodynamic framework in which this relationship can be reconsidered.

To give an analogy, it is as if, after Kikuchiyo had already fought courageously and proved through his actions that he was a true samurai, an authentic ancient genealogy were suddenly found showing that he was, after all, of samurai descent.

To summarize, in the paper we calculate the steam-engine power, estimate its magnitude under terrestrial conditions, and then compare it with an independent estimate of wind power, finding close correspondence. We also show that the earlier CIAD relation is a major part of the steam-engine power, thus providing it with solid thermodynamic grounding.

Second story: What Is Bigger?

A subspecies of the narrative “the effect is small,” which has accompanied the biotic pump since its birth, was the idea that this effect is smaller than the effect of latent heat release during condensation — whatever these “effects” may represent in measurable terms.

Condensation does two things at once. It removes water vapor from the gas phase, such that there is less gas around. When the condensed water precipitates, mass is also removed from the atmospheric column. But condensation also releases the energy that was spent on evaporation — the energy required for water molecules to break free from the liquid and enter the vapor phase.

The argument goes like this. Suppose precipitation removes a certain amount of water from an atmospheric column, reducing its weight and hence reducing air pressure at the surface. But the same condensation releases latent heat and warms the air. Since warmer air expands, this warming is assumed to produce a pressure effect larger than the pressure decrease associated with the removed water.

There are two problems with this argument.

The first is that, for condensation and precipitation to occur, rising air must cool, not warm. Thus, when speaking of latent heat “warming,” one is actually comparing condensing air that cools less with some reference air that would cool more in the absence of condensation. Depending on how this comparison is made, the conclusion can differ.

The second point is that, for a column of fixed mass, warming of the air aloft does not by itself increase air pressure at the surface. Surface pressure is determined by the weight of the atmospheric column. Warming changes how pressure differences are distributed with height; removal of mass changes pressure in the lower atmosphere and at the surface.

Therefore, latent heat release and removal of gas by condensation and precipitation do not simply produce two opposing effects that can be compared by asking which one is “bigger.” They create pressure gradients in different spatial domains, with different dynamical consequences.

There is also a more sophisticated historical parallel related to the same problem.

More than a century ago, Max Margules evaluated how much work could be produced by surface pressure perturbations if the atmosphere relaxed from a given state to a static, horizontally isothermal state. He found that the available work associated with surface pressure perturbations was small compared with the kinetic energy of observed hurricane winds.

This reasoning later became part of the background against which atmospheric available potential energy was understood. In a static formulation, the available energy associated with pressure perturbations is proportional to their square. Therefore, if surface pressure perturbations are several times smaller than temperature-related pressure perturbations aloft, their static available energy can indeed be much smaller.

Height-latitude plot of kinetic energy generation. Note the large areas with negative generation in the upper atmosphere: here the air must move against an adverse pressure gradient. Source: http://arxiv.org/abs/2605.23875

But here is the key point: small static available energy does not imply small kinetic energy generation. And vice versa, large static available energy does not imply large kinetic energy generation.

Near the surface, friction makes air cross the isobars, and a surface pressure gradient can therefore continuously generate kinetic energy. Aloft, pressure gradients can be larger, but fast air motion may proceed largely along the isobars — or even against an adverse pressure gradient, as the negative areas in the figure show.

In this sense, the historical argument was important, but it became a distraction when static available energy was taken as a measure of the importance of a pressure gradient in a dynamically maintained circulation. The biotic pump is not a proposal that a disturbed atmosphere quietly relaxes to a static state. It is about a continuously operating moist circulation, in which condensation and precipitation can maintain surface pressure gradients, and friction allows these gradients to generate wind.

So, if you are a biotic pump supporter and are confronted with the argument that the effect must be small compared with latent heat release, you can respond:

Latent heat release shapes pressure gradients primarily through temperature differences aloft, while condensation and precipitation alter column mass and surface pressure in the lower atmosphere. These effects act in different parts of the circulation and are not directly comparable by saying that one is bigger than the other.

And if the dialogue continues, your position becomes even stronger when the logic of our third story is brought in: rain-driven kinetic energy generation in the lower atmosphere and temperature-related pressure gradients aloft do not compete, but work together.

Third story: The Beauty of Rain-Driven Winds

When I look at the colors in old paintings — like this masterpiece by Piero di Cosimo, which filled me with awe when I saw it in the Uffizi Gallery in Florence with Ugo Bardi — I feel that these colors were as deep and solid as the earth herself, nourishing body and soul. There was beauty around, and at least some of our ancestors had time to contemplate it, perhaps without knowing how transient it was.

Much of this beauty is now being lost.

The physical processes that shape our climate are not beautiful in the same direct way: pressure, condensation, motion and work do not nourish the eye and soul like a living landscape. But caught in clean and elegant physical laws, they open to the human mind, and beauty can be seen in them too.

Through this lens, the available data tell us something beautiful: the steam-engine power approximately coincides with the total atmospheric power on Earth — water lifting and wind generation combined. At the same time, our analysis shows, in agreement with CIAD, that precipitation-driven kinetic energy generation occurs predominantly in the lower atmosphere.

How can this happen?

Let me tell an imaginary story about three planets.

First, imagine a planet with a dry atmosphere. The Sun heats this planet mercilessly along the equator. The air there is much warmer than over the poles, and the warm atmospheric columns have higher pressure aloft. This surplus pressure pushes the air toward the poles.

But the planet rotates. Air moving toward the poles, toward the axis of rotation, acquires a fast motion around this axis, and the associated centrifugal force opposes further poleward motion. Instead of freely running from high to low pressure, much of the flow proceeds along the isobars.

The temperature gradients are there. The store of potential energy is there. Some kinetic energy generation is possible. But there is no reason to expect it to reach the power of our moist and raining Earth, where water itself enters the game.

As Heinrich Hertz wrote more than a century ago:

If the atmosphere were dry, the temperature differences existing in it would by themselves give rise merely to movements of minor significance.

Now imagine a second planet. This one has an ocean and rain, but no horizontal temperature differences. Such a planet is far more imaginary: to keep her equally warm everywhere, we would probably need to surround her with several suns.

On this strangely warmed planet, rain removes water vapor from the atmospheric gas phase and decreases pressure in the lower atmosphere. Near the surface, where there is friction and the flow cannot simply follow the isobars, air moves from high to low pressure — toward the rain. This motion brings more moisture into the precipitation area and sustains the pattern.

Down below, the atmosphere is working vigorously. Kinetic energy generation in the lower branch can be large.

Then the air aloft has no other choice but to close the circulation initiated by precipitation below. Since there are no temperature differences, the pressure difference created near the surface remains adverse for the returning air in the upper atmosphere. To complete the circulation, the air must move against this adverse pressure gradient, consuming almost all the kinetic energy that was generated below.

Thus this rainy but horizontally isothermal planet can have strong rain-driven kinetic energy generation in the lower atmosphere and still have little total kinetic energy generation. What she makes below, she loses aloft.

By the way, tropical cyclones provide a very real analogue. They develop over a nearly uniform warm ocean surface, with enormous kinetic energy generation in the low-level inflow. But in their upper-level outflow, rapidly moving air proceeds against an adverse pressure gradient, producing negative kinetic energy generation and offsetting part of the work generated below.

And now let us return to our Earth.

She has both: the temperature contrasts of the first planet, and the oceans and rain of the second. Precipitation decreases pressure in the frictional lower atmosphere and generates air motion from high to low pressure. But now temperature differences change how this pressure difference varies with height.

Here the temperature gradients that were largely locked on the dry planet acquire a new role. They do not have to provide the main kinetic energy generation in the lower atmosphere: precipitation does this. Their role is to prevent this lower-atmospheric work from being undone aloft.

The air rising from the lower branch has already lost much of its newly generated kinetic energy to friction. It cannot sustain an extensive upper-level return flow against a comparable adverse pressure difference. For the circulation to continue, this adverse pressure difference aloft must become small or reverse sign. This is what the temperature contrast makes possible.

The pressure gradient can remain strong near the surface, where rain drives kinetic energy generation, while becoming very small or slightly favorable aloft. In our analysis, the upper-atmospheric contribution to kinetic energy generation just barely exceeds zero. But it does exceed zero: it no longer cancels the large positive generation below.

Thus the two mechanisms meet. On the dry planet, differential heating creates a store of potential energy, but without the moist power pathway much of it remains locked. On the isothermal rainy planet, precipitation generates kinetic energy below, but nearly all of it is taken back aloft. On our living, thriving Earth, precipitation makes the lower atmosphere work, while temperature differences prevent this work from being undone above.

The result is that total atmospheric power — the power of lifting water and generating wind combined — is approximately equal to the power of Earth’s atmospheric steam engine.

So rain does not merely fall from an atmosphere already set in motion by something else. Rain itself is part of what makes the atmosphere move.

And when you look at a tree, think of this as well: it is an enabler of the atmospheric engine over land, feeding it with its working fluid — water vapor.

We need to respect trees.

Related reading:

In anticipation of the Convergence, I was delighted to be interviewed together with John D. Liu — one of the world’s most eloquent voices for restoring degraded landscapes and rethinking human civilization around ecological function — by Emmanuelle Chiche and Megan Lindow from StoryMoss. Below is a slightly abridged transcript of the interview, which can also be watched on YouTube.

Restoration and preservation of nature form a philosophical Möbius strip, weaving into deeper questions about our existence — and, as I see it, not without controversy.

Opening: Different Paths Converging Around Nature

Emmanuelle:
Hello, StoryMoss viewers. Hello, John, Anastassia, and Megan. We are really, really happy and honored to be with you today as we invite more of the world to join the Global Earth Repair Convergence, founded by Michael “Skeeter” Pilarski, happening in early May in Cascadia and online.

We thought of inviting both of you for what may perhaps be the first one-on-one conversation with us in the background about your amazing work.

Anastassia Makarieva is a Russian atmospheric physicist and one of the originators of the biotic pump concept and the biotic regulation framework, which offer essential insights into healing our degrading world. John D. Liu is a filmmaker, activist, land restorer, and so many other things. Thank you both very much.

Megan is joining us from Cape Town, while John is in Los Angeles, Anastassia is in Russia, and I am in New York. We are here together today. Megan?

Megan:
Yes. Hello, everyone, and welcome. We are going to have a story-weave today.

I wanted to ask both John and Anastassia, first, what draws you specifically to the Global Earth Repair Convergence. Beyond that, as we were just noting in our discussion, so much of your work, Anastassia, points to the need to preserve ecosystems — these complex forests that remain around the world even as we are seeing such rapid rates of destruction and deforestation.

And John, as a filmmaker with a long background of discovery — from traveling as a journalist to really learning about natural processes and ecosystems, and then weaving that knowledge into large-scale efforts at landscape restoration — you come to this restorative work across landscapes that have already been disturbed, and from a background of covering politics and geopolitics.

So, as each of you tells us a little more about your work, I would also love to hear what fascinates you most about each other’s work, and what you are hoping to explore and discover in this conversation.

Maybe we can start with you, Anastassia.

Anastassia:
Thank you, Megan. It is my great pleasure to be here.

I have been working all my life as a physicist, investigating the role of natural systems in sustaining a habitable climate on Earth. In this habitability, water is a key ingredient. Much of my recent work has therefore been devoted to investigating the role of terrestrial ecosystems in facilitating the water cycle on land, particularly its atmospheric component: moisture transport from ocean to land.

The biotic pump concept, which Emmanuelle mentioned, describes the active role of natural vegetation in driving the water cycle — particularly in ensuring that moisture evaporated over the ocean comes to land, precipitates over land, and feeds the water cycle and all life on land.

This is largely theoretical, fundamental research. What fascinates me in John’s work, as you said, is that these are real efforts to which our knowledge could contribute. This knowledge can be spread and converted into real actions that engage people all over the world in a network where they stop destroying and begin doing something more positive, coming into greater harmony with nature, which I believe is our future.

Megan:
Thank you, Anastassia. John?

John:
Thank you very much. It is a great pleasure to have this opportunity to speak with you all.

I certainly came from a different beginning point. I was really a professional observer for my entire life. I tried to tell the truth and to understand what I was seeing at any given time.

It was very exciting and interesting to watch major political events, economic developments, cultural changes, and so on over the course of my life. But when I found that the Earth systems were massively degraded in all the cradles of civilization, and I had the opportunity to go to many of these places, I began to look at them and consider what I understood of the history — or what I could find out from the history, from sediment layers, from fossil remains, and from what was already known.

I began to realize that I had very little information about this. I thought I was fairly experienced and educated, but there I was, looking at the basis of living systems, and I did not really know enough.

Then I was very fortunate. I was asked by the World Bank to film the baseline study of the rehabilitation of the Loess Plateau in the upper and middle reaches of the Yellow River. In doing that, I realized that it could not always have been the way it was. I had to do a kind of forensics: to look at the crime scene and say, “Well, I see the body, I see the blood, and now I’m looking for whatever instrument was used to murder this thing.”

Ultimately, what I found was that I was studying dysfunction. It was necessary to understand the dysfunction fully if I wanted to see it another way. From my position as an observer, I was in some ways representing humanity, because humanity was not aware of what was going on. For thousands of years, human beings had been destroying the life-support systems of the planet.

I was given many fellowships to study, so I became an accidental student. I started to realize that this could be defined if we used these forensic methods to look at what had happened.

I found that all fully functional places have massive biodiversity. They have higher and higher canopies. Perennial polycultures replace annual plants, and there are no exposed soils whatsoever. In a functional terrestrial system, unless you have plate tectonics, earthquakes, volcanic activity, meteor strikes, or something like that, you generally have total vegetative cover.

There are some interesting differences in some deserts, but my conclusion is that most deserts are not natural deserts.

The Chinese experience in restoration shows very quickly that restoration can go faster than we thought. Maybe we really need to go to the worst places — the most degraded places, where early civilizations began and destroyed their environments. That also links with some permaculture understanding: you have to work at the edges. The edge is where there is a lot of variation.

One of the biggest realizations for me was that the percentages and total amounts of what I would call necromass — decaying dead biomass — are critically important. Almost nobody knew anything about this. This dead biomass is also the habitat for the microbial and fungal communities that make mineral nutrients bioavailable to plant life.

Another important point, which I think is very close to what Anastassia is working on, is that once you have degraded the system, you find that biology had self-organized over prodigious time to alter the physics.

Then all the criteria become larger and larger: the temperature differentials, for example. I have seen temperature differences of 45°C between exposed soils in deserts and areas beneath artificially induced vegetative cover. That cover was grown through extreme methods: saline irrigation and the use of halophytes. But it was functional, and it worked.

If we can do that, we can hold moisture in the lower hydrological cycle and recycle it near the Earth. Looking at this, it struck me that this is exactly what needs to be done. Every human being needs to understand that we are in a symbiotic relationship with all other life forms. It is ridiculous for us to imagine that our abiotic infrastructure is the basis of life. It is not.

I am talking too much. Sorry.

Complexity and Simplicity

Megan:
No, it is fascinating. I am really appreciating this aspect that I have heard from both of you, in different ways, about the human relationship to the natural world, and how we need to grow our understanding and heal our hearts at the same time in order to achieve what we are all gathering for — both in place and online — in this Global Earth Repair Convergence.

There is so much knowledge emerging. But I want to turn the conversation a little poetic for a moment, if I may. I was inspired by hearing both of you speak in various recordings about your work.

I wanted to ask whether you could each talk about an experience you have had in the natural world — an experience of very deep connection — and what insight that brings you about repair and going forward. I know you must both have innumerable such experiences, but perhaps, Anastassia, you could begin. How does it feel when you stand in one of these vast forests in Siberia, or at the river, and see what your work has uncovered — the flying rivers, the biotic pump, the physics actually happening in this place?

Anastassia:
Thank you, Megan.

John mentioned that he traveled a lot, saw many ecosystems, and learned from them. Personally, I have spent a lot of time in boreal forests — many years, if I count all the months together. So I also have this first-hand experience of how nature works.

Unfortunately, not many people have this. What I would say is important is that when you are there, in what John refers to as a functional ecosystem, you understand that it is very complex. It is basically the most complex thing or process that one can imagine.

When you see this, it sets a standard for understanding complexity: what complexity is, and what complexity is required for function.

The challenge is how to communicate this idea of complexity to people who have not seen it first-hand, and who may believe that we can simply put a green thing in a pot, bring it to the desert, water it, and then something will start going there.

This complexity — I do not know how to express it in poetic terms — is a very profound feeling. It is overwhelming. This is what I am trying to bring into my scientific research: to formulate it in scientific language so it can be understood and shared by all people.

So this is my response: complexity. The unmatched complexity of the living world.

Emmanuelle:
That is beautiful. Thank you so much.

As we were preparing to meet with you and watching many more recordings, we were going slowly, trying to get the depth of your inquiry. For StoryMoss, going back to Joanna Macy’s work on deep ecology — opening our hearts, paying more attention, and listening — I think that is what Megan was trying to bring in with the poetic question.

I have been reading a lot of both of your work. There is a lot of eco-philosophy, critical wisdom, mindfulness, and the stage where many more of us, when we reach that moment, begin to pay more attention and engage. We begin to feel that we can do something.

I think the problem is that too many of us think we cannot do anything, that we are doomed. But both of your work brings hope — active hope. That is what we are also trying to bring through the complexity.

John, did you want to respond?

John:
Yes. I would like to say that I agree: the complexity is infinitely complex. But there is also a very elegant simplicity in nature, which is quite beautiful when you find it.

Nature follows a logic. Ecology and logic are closely related, and that is really important. What we see now with our economic and political systems is that they are extremely illogical. They are about power, dominance, or greed. These are not very wise perspectives.

I would also like to say that many people consider that we are physical beings struggling or striving to have spiritual experiences. But it seems more likely that we are spiritual beings experiencing physicality for a short while.

In doing this, it shows us a bit of a purpose in life: we are meant to bring life, to bring consciousness to life. We are just not very good at it yet. We have been expressing ourselves more like parasites, as if we are going to destroy our host and then die with the host. That is ridiculous.

Likewise, the idea that we should acquire more and more material possessions or power for ourselves is a mistake. As a journalist, in all my observations, I noticed that we are all going to pass away. We will return to where we came from. The person who dies with the most stuff does not win anything.

There is a mistake here. I think it is also about joy and beauty. What we see in nature has such elegance and beauty. What I see now, even here in Los Angeles, in many films for example, rarely shows tremendous beauty or profound thought. They are mostly violent, or about greed, or about more things, grasping, and low-energy behavior.

I think we can do better. We should do better. We are supposed to do better. We have all the information we need now. We have the ability to feed everyone on the planet. I do not think that is a problem if we share and work to do this.

But if we think that the basis of wealth is material things, then we are bound to fail. It will be very difficult to take care of eight, nine, or ten billion people. But if we understand that nature is expressing perennial polycultures and consistent, self-replicating life — that it is breathing, and because it is breathing, we are breathing — then we realize we are part of it. We are a bivalve. We could act as any other organism that breathes, or filters the water, or takes in food.

And it has to be organic — without poisons, without pollution. It is insanity not to do that.

So I think we have enough information. We have our marching orders. We have work to do, and this needs to be the central intention of human civilization.

Doing and Non-Doing

Megan:
When you mention breathing, I want to pick up on that. When I was discovering your work, Anastassia, I had the impression of the forest — the biotic pump — as the forest breathing in a way, generating its own self-sustaining water cycles.

To return to the really complex nature that you both speak about, and the challenge of how humans learn this complexity when not everybody has the opportunity to experience it: at the same time, there is so much that we know now. Some of it is perhaps ancient knowledge that has been lost through modernity, colonization, and other processes of destruction.

That brings me back to the inspiration and active hope that need to come with this challenge: stepping up, doing things differently, and integrating this understanding that we are developing as humanity.

If either of you has a response?

Anastassia:
If I pick up from breathing: actually, the biotic pump has also been compared to the beating heart of the forest, because it pumps like a heart. It pumps moisture.

But I would also like to bring in the idea of balance. John mentioned complexity, simplicity, elegance, and logic in nature, and I totally agree. Another perspective I would like to emphasize is doing and not doing.

People are doers. We can easily be energized for a good cause — to do something, to plan things, to restore. But another important thing is not doing what should not be done.

Once we energize ourselves to restore something that we have destroyed as doers, we must at the same time put limits on further destruction of this water pump — this still-beating heart of the world’s great forests: the Amazon, the Congo, Indonesia, Papua New Guinea, Canada, Russia. These forests are alive. They have been exploited and are being exploited, but they are still alive. They can regenerate, and they can teach us this complexity, simplicity, and elegance.

We will not invent it. We should not be too self-confident. We cannot invent nature. But we can learn, and we can let nature guide us through self-restoration.

We must stop the destruction. Doing and non-doing: that is what I think.

John:
What she said.

Megan:
Beautiful.

Emmanuelle:
Yes. John, do you want to take this on?

The Ability to Understand

John:
One thing crossed my mind because Anastassia said many people might not have this experience. I am not sure that is true.

I remember having a fellowship at Rothamsted Research in the UK, an agricultural field station. They created the RothC carbon model, which is part of the basis for understanding disruptions to the carbon cycle.

The director invited me to come. He did a lot for me. He sent me to Africa, and I was able to really see the Congo Basin and work closely with a number of countries there for a while.

What was very interesting was that I had to give a lecture. They had all these quite famous scientists, and I was wondering what I would do if I gave this lecture and they just looked at me. I did not really know what it would be like.

When I gave the lecture, at the end a rather well-known scientist came up to me and said, “Hello.”

I said, “Hello.”

He said, “You seem to know what you are talking about.”

I said, “Well, thank you.”

Then he said, “If you can understand it, anyone can understand it.”

And I thought: yes, that is true. If I can understand it, anyone can understand it.

That is where we need to be. This needs to be common knowledge throughout humanity: we are drinking water, we are breathing air, and soils are the basis of the food we eat. These systems need to be fully intact. Biodiversity is normal. Reducing things to monocultures is unknown in nature. Nature is outrageously biodiverse.

Because of the symbiosis between systems, we are killing ourselves if we destroy them. Once we understand this, we must see that wealth in the world does not come from buying and selling things. It comes from the natural functioning of Earth systems.

Every living being has the right to life. It is outrageous to imagine that we should decide, with prejudice, what lives and what dies. If you understand how extinction events work, you find that the top of the food chain is most at risk. That should give us some thought, because we are at the top of the food chain. It is outrageous that we could even be in a situation where this is possibly happening.

The anger and painful sorrow that are around all the time — this is not natural. You do not find that when a baby is born and looks at the world, fascinated by everything. This is taught behavior. We should be really careful to teach joy and the harmony that exists among all life. That is where we need to focus.

One thing we have been working on recently — over the last nine years — is ecosystem restoration communities. What we are seeing is that people can come together and work together. When they do, they can do more than they can as individuals. They can study together and understand together. Physically, mentally, imaginatively, and intelligently, together we are stronger.

By ourselves, how are we going to restore the Earth? The problems are huge. But if you think about them the way the Chinese think about them, you say: “Okay, we are a swarm. We are a hive of bees. We are ants. An ant can only carry a tiny thing, but when all the ants come together, they can pick up everything.”

Then you realize that change can happen rapidly. How long did it take China to raise hundreds of millions of people out of poverty once they recognized that soils, water systems, and biodiversity were important? It changes rapidly because they make it the central intention of civilization.

We have to realize that we are not different. We are one species. This is a planetary issue. It is not up to China, the United States, Russia, Europe, or any one place. It is up to humanity as a species to act on a planetary scale. That is the only way we can change this.

Now we look at our economics, and we have billionaires and billions of poor people. This is ridiculous. Everyone has an equal right to life. Who among us can say, “No, I deserve everything. Give it all to me”? That is gross. That is disgusting.

If we learn to work together, these ecosystem restoration communities can come together — 250, 300, 500 people — and make community land trusts. They can say, “Everyone in our community is going to eat. Nobody will go hungry. Nobody will be without housing.”

Then we can come together and do our best to ensure that everyone has a house, everyone has food, and everyone has meaningful work. Right now, we are forcing billions of people to behave like indentured servants, running around doing things that are often destructive, when we need everyone to do the right thing.

We should all be grateful for the opportunity to do the right thing. We should all be happy to do the right thing. Then we will all be well fed and healthy, and we will watch as the next generations inherit a fully functional Earth. That is where we need to be.

Restoring and Preserving

Emmanuelle:
Thank you, John. It feels so good to listen to both of you.

For the last few minutes of our time together, Anastassia, if you would like to close, I also want to express our gratitude for the friendship, for the Convergence, and for Michael Pilarski’s work. I think you have come more than once, and I know Michael loves that.

The movement he has been building for about fifty years, together with his team and the think tank, is exciting: 120 speakers online and in person, and then ongoing work after the Convergence. There is so much that will be shared. It will take a while to watch it all.

And there is also the call for one billion actors to repair the Earth in three years. The shift your work is helping make is so important: yes, carbon emissions are very important, and stopping them matters, but we also have to look at forests, oceans, and grasslands as having solutions. We have to let nature guide us through healing.

That brings so much hope, because then we do not only think about carbon emissions and feel bad. We can see that nature is still doing it. How can we honor and respect that, and continue to engage with and enjoy the gift of life?

So thank you so much, Anastassia. Would you like to close us with a few words?

Anastassia:
Yes. I think this is a very important endeavor that Michael and his team are championing.

Spreading knowledge and explaining things to people is essential. As John said, everybody can understand — and I totally agree. It is difficult to communicate feelings, because we have diverse backgrounds. But we can encode those feelings in a universally understandable language, because we are the same species.

The question is how to make this knowledge engaging, how to make it spread, and how to create an ignition — when people begin to burn with these noble feelings from within and energize each other.

I think this event is very important in that respect, and I wish it every success. Unfortunately, I cannot go in person, but I will participate online.

Emmanuelle:
Anastassia, you are mainly in St. Petersburg?

Anastassia:
Right now I am in St. Petersburg. But soon we will travel to Siberia, to the taiga forest.

Emmanuelle:
Wow.

Anastassia:
It is not possible to study something that you have not seen and felt. That is very important, because formulas do not communicate the full truth. But when you have seen the truth, you can write down the right formula — one that will have meaning, hopefully. That is at least how we think about our work: trying to make it meaningful.

Megan:
Beautiful. Do you have internet there in Siberia?

Anastassia:
No, no, no. No way. We do not even have electricity. You are totally immersed in nature.

We let ourselves be in nature. It is also a very particular emotional and spiritual experience, because you detach from the digital world and tune entirely to the green revival of nature.

In Siberia, spring comes and winter becomes summer very quickly. You see this burst of life coming from almost nowhere, and it carries you away with its wave. You feel that you are reviving.

And there are lots of mosquitoes. You go through all of this like any animal, and you feel that you are becoming part of it. That is very important.

Megan:
So you actually experience a different way of being human.

Anastassia:
Yes. We become part of the ecosystem.

Emmanuelle:
John, have you been to Siberia, to the taiga?

John:
I have been throughout the Soviet Union. Probably the most interesting is that I have been to Mongolia 30 or 35 times, up to where Lake Baikal is. I have also been several times on the Trans-Siberian Railway, so I got to see it.

But I would love to spend more time there. I also went closer to Moscow, looking at peatlands surrounding the city. They had been drained, as in many other places, but some of the most beautiful remaining places are there. Beavers have been coming back and restoring them. They were quite lovely. We need to do that all over the world as well: restore these wetland systems.

In some places of Europe, wetlands are being restored. Belarus is a conspicuous example

Los Angeles is absolutely the worst. I will have to share some of the work of a very interesting and lovely Chinese colleague who unfortunately passed away, Professor Yu Kongjian. He worked on the sponge city and sponge planet movement. They have done a thousand projects, mainly in estuaries where rivers meet the sea. They are just beautiful.

Then you come to Los Angeles and see this stupidity: concrete in the bottom of the Los Angeles River. It does not flow. It is all about rushing runoff out to the sea as fast as possible, when in fact they need all that water here. And of course they had the terrible fires burning down houses. It was ridiculous.

Outlook

Megan:
John, I know we are coming to the end of our conversation, but this is an aspect of your work that I find really interesting and have a lot of questions about: the diversity of places and ecosystems you have traveled to around the world.

On the one hand, there must be universal principles or ideas behind restoration. But at the same time, each ecosystem and each place has its own unique lifeways, cultures, and history. I would be fascinated to hear more about your learning process and how you think about engaging restoration in different contexts.

John:
Well, we would need quite a lot of time for that.

Emmanuelle:
Next episode.

John:
I would say that there are principles, and that this is one Earth. It is a single planet. As a planet, it is the interaction among all of the systems together that makes it functional.

We have nearby examples, such as Mars and Venus. If we look at those and start to think about what happened there, we have to look at the atmosphere, the water cycle, and the relatively benign temperatures that we have experienced here.

This is also a question about humanity: the rise of humanity, as opposed to other types of organisms. This interglacial period that we have emerged into is not normal, but it is here. Yesterday we were talking about coincidence or serendipity. It is like a miracle. It is a miracle that we have a planet like this, and that we live on this planet. It is wonderful.

We should be aware of that, and not live in selfish materialism. The Chinese concept of ecological civilization is very important, but it should be defined by consensus among people around the world — not by one culture alone.

China had to face the danger of starvation with a huge population of 1.4 billion people. Through rapid industrialization, moving from organic gardening to becoming the world’s manufacturing center, they also had to face pollution. They could not be terrified of the pollution; they had to deal with it.

The West has spoken a lot about electrification and reducing emissions. That matters, but it is not where true wealth lies. True wealth lies in restoring ecological function to everything.

That is what is going to happen. I used to get frustrated because I thought nobody was really listening to me. But the fact is that this is the truth, and there is no way that it will not be. It will happen either with human beings or without human beings. So we had better get on the right side immediately, so that we can enjoy this beautiful planet — and so can our children.

Emmanuelle:
It is very exciting. The world harmony, the world joy — when we speak with all of you, there is so much happiness and joy in the way your hearts are working and pulling your lives toward solutions. That is what nature wants us to do. I think nature wants us to do it together.

We are finally realizing that we can be part of the miracle on this miracle planet. The joy of coming together in that realization is what we all hope for.

Thank you so much for your big hearts, for all your insights, and for your great healing energy.

Megan:
Thank you. It has been so lovely, illuminating, and fascinating to be with you both. I really appreciate your sharing your insights with us, and I hope this is the first of many conversations.

Anastassia:
Thank you.

John:
Thank you.

https://www.globalearthrepairconvergence.com/

Related reading:

Disclaimer: Water availability (WA), water yield (Y) and runoff (R) are used interchangeably in this mini-series, with their very subtle differences discussed in Part I: Basic Notions. Evapotranspiration is denoted as either ET or E.

Increasing Precipitation and Water Availability, Decreasing Transpiration?

Figure 5a from An et al. (2025), showing ERA5 reanalysis trends in precipitation P, evapotranspiration ET, and water availability WA = P - ET during the two decades of re-greening.

We can see that water availability increased, while evapotranspiration decreased, during the studied period. This is the opposite of what a reader might take from the abstract of An et al. (2025), where land use and land cover changes (LUCC) are said to have increased evapotranspiration and decreased water availability:

Readers who do not examine how these results were obtained, and media reports that repeat the headline conclusion, may therefore miss the central point.

The direct ERA5 pattern is different: over the last two decades, water availability in China has been slightly increasing. Precipitation has been increasing as well, while evapotranspiration has been decreasing. How should we interpret this? And how can evapotranspiration decline over a re-greening area?

There are two possibilities.

The first is that the evapotranspiration trend itself is uncertain. As discussed in Parts I and II, evapotranspiration is not measured directly over large areas. It has to be inferred from flux-tower data, satellite information, land-surface models, and multiple parameterizations.

The most robust estimates usually come from watershed-scale mass balance: we measure precipitation, we measure streamflow, and we estimate evapotranspiration as the difference between them. But this method is not local. It depends on river-basin measurements, which remain uncertain in many regions. In China, consistent national-scale streamflow data have only recently become available (Wang et al., 2025).

This means that an evapotranspiration trend estimated as the difference between precipitation and runoff trends accumulates the uncertainties of both. It cannot be more robust than the underlying precipitation and runoff data.

It may therefore be that actual evapotranspiration in China has been increasing, together with rainfall and runoff. This would be similar to the wet-season pattern inferred for the Loess Plateau by Tian et al. (2022), using a different reanalysis product, MERRA-2.

A summary of discussed trends, Table 1 from https://arxiv.org/abs/2604.09510

The second possibility, which we discuss below, is related to ecosystem processes.

Ecosystem Recovery, Atmospheric Dynamics, and the Water Cycle

When an ecosystem begins to recover from a major disturbance, plant biomass increases. Transpiration increases as well, adding moisture to the atmosphere. If plants have enough water to sustain transpiration, then as vegetation recovers, the atmosphere above and around it can become moister. This is indeed what has been reported for China: re-greening has been associated with an increase in atmospheric moisture content (Jiang et al. 2013).

At the initial stage of recovery, we can therefore expect a positive correlation between transpiration and atmospheric moisture. Atmospheric moisture, in turn, affects the probability of precipitation, but in a non-linear way. When moisture content is low, and the atmosphere is still dry and far from the dew point, adding more moisture may have little effect on precipitation. This is the dry regime: atmospheric moisture and transpiration increase markedly, while precipitation changes more slowly, if at all.

In this regime, shown in the picture below to the left of the red dot, water availability, or runoff, indeed decreases as transpiration increases:

ΔY = ΔP − ΔE < 0, because ΔP < ΔE.

Conceptual relationship among atmospheric moisture content, stage of ecological succession and changes in hydrological variables—precipitation P, evapotranspiration E and water yield Y=P-E —relative to their initial values. The red dot marks the transitional point at which the water-yield trend becomes positive. Fig. 2 from https://arxiv.org/abs/2604.09510

If the ecosystem is allowed to recover further, the atmosphere may eventually become moist enough for atmospheric dynamics to change, condensation to intensify, and precipitation to increase rapidly. At the same time, transpiration does not increase as readily in an already moist atmosphere. This is the wet regime: water availability begins to rise as evapotranspiration grows slowly and precipitation grows rapidly:

ΔY = ΔP − ΔE > 0, because now ΔP > ΔE.

If we recall the three-stage scheme discussed in Part II, in the section “Re-Greening and Moisture Convergence,” then early succession in the figure above corresponds to panels (a, d), intermediate succession to panels (b, e), and mature ecosystem to panels (c, f).

If a region alternates between dry and wet regimes during the year, recovering vegetation could affect the water budget in different ways in different seasons. During the dry season, better soil cover could reduce direct evaporation from previously bare soil, thus increasing water availability. During the wet season, vegetation could increase transpiration, when additional moisture input to the atmosphere is more likely to enhance moisture convergence and precipitation, thus raising water yield, as in the Loess Plateau example shown in the table above.

Depending on the relative magnitudes of these seasonal effects, annual mean water availability could increase even if annual mean evapotranspiration declines. This could happen, for example, if reduced dry-season evaporation from bare soil outweighs a smaller wet-season increase in transpiration.

This is the second possible explanation for declining evapotranspiration in a re-greening region. The downward trend may reflect a reduction of uncontrolled evaporation during the dry season, due to better soil cover, combined with a smaller increase in transpiration during the wet season, when most moisture convergence and precipitation occur.

This is the essence of ecological succession as a water-cycle process: reducing unnecessary moisture losses while making more effective moisture “investments” through transpiration, at the time when these investments are most likely to support atmospheric moisture import and precipitation.

This dual hydrological behavior during ecological restoration parallels the ecological concept of a landscape trap (Lindenmayer et al. 2022). Mature, relatively undisturbed forest ecosystems tend to be hydrologically stable and resistant to droughts and fires (Xiao et al. 2023; Wolf et al. 2023). Logging or other disturbances can shift such systems toward early successional states that are less hydrologically competent. If disturbance exceeds a threshold, the system may enter a trajectory of drying and burning from which recovery becomes increasingly difficult. The inability of early successional systems to stabilize a moist regime is consistent with the characteristics of the dry hydrological stage shown in the above figure.

In China, contrasting assessments of the relationship between water yield and ecological restoration may reflect the complexity of these ecological processes. After two to three decades of re-greening, large areas remain in relatively early successional stages, often dominated by naturally recovering grasslands rather than planted tree stands (Yu et al. 2023).

In such conditions, analyses confined to moisture recycling alone may suggest that further ecological restoration threatens local streamflow. However, if restoration is viewed as a dynamic progression between hydrological regimes, short-term reductions in water availability may be followed by a trend reversal, with water availability beginning to grow.

Conversely, ecosystem destruction should lead to a decline of the water cycle. Recent global forest-change assessments indicate that the dominant hotspots of forest loss and disturbance during 2000–2020 were tropical forests in the Amazon Basin, the Congo Basin, and Southeast Asia, together with extensive tree-cover loss and disturbance in boreal regions of Canada and Russia. In contrast, several temperate and subtropical regions, notably parts of Asia, have exhibited net forest and vegetation gain over the same period, driven in particular by large-scale re-greening in China and India.

Consistent with this pattern, global maps of water-yield trends for 2000–2020 highlight tropical regions, Canada, and Siberia as areas with a tendency toward declining water yield, while India and China stand out as among the few large regions where water yield has increased, at least at regional scales.

Fig. 1B from Zhang et al. 2023. Global trends in water availability in 2001-2020.

Summary

In this mini-series, I wanted to describe some caveats that a general reader may miss in the scientific literature on the vegetation-water nexus. But I also wanted to present an ecosystem perspective on water-cycle recovery, and to highlight the complexity of these processes.

The caveats. If you are a water-cycle practitioner, ecosystem restorer, or forest protector looking to the scientific literature for guidance, it is useful to pause whenever you encounter a statement such as: “[deforestation, afforestation, replanting] caused [runoff, precipitation, cloudiness, evapotranspiration] to increase or decrease.” The first question is simple: did the variable itself actually increase or decrease in the studied region over the studied period?

If the observed trend has the opposite sign, or no clear trend at all, then the reported “vegetation impact” is not a directly observed change. It is a reconstructed effect, obtained by separating vegetation change from the broader climatic background using a particular set of assumptions.

This does not automatically make the result wrong. But it means that the conclusion depends on the method. The assumptions used to isolate the vegetation effect may be appropriate for the region studied, or they may not. They may also miss important processes, such as vegetation effects on atmospheric circulation. If the reported vegetation impact is reconstructed rather than directly observed, the next step is to examine the method: how was vegetation change separated from climate variability, and which effects of vegetation were included or excluded?

Ecosystem perspective. Water is cycled on land through complex and interrelated processes. We still know relatively little about many of them, especially over long timescales and at large spatial scales. This is why the best strategy is to make nature our ally and follow the natural process of ecological succession as closely as possible, allowing the water cycle to recover through ecosystem self-restoration. Where recovery is active and human-assisted, the same principle applies: mimicking natural processes is often reported to be the most productive way forward (Andrade et al., 2020; Pasini et al., 2021).

The high hydrological competence of minimally disturbed ecosystems, together with the slow nature of ecological succession, provides a strong rationale for preserving natural vegetation wherever it remains. Within China, there is increasing recognition that tree cover constitutes a foundation of environmental stability. A consistent extension of this principle is to support the protection of natural forests beyond national boundaries, particularly in Eurasia and the tropics, where deforestation exerts a disproportionate influence on atmospheric circulation and climate stability. In this context, the concept of Ecological Civilization advanced by China can be understood not only as a national development framework, but as a basis for coordinated global action to preserve one of the Earth’s most effective climate-regulating systems: natural forests.

Photo by Alexei Aleinikov

Related reading:

In Part I, we discussed why it is so difficult to measure the invisible part of that cycle, especially evaporation and transpiration.

With plants in pots, this would be easy. They evaporate and transpire exactly as much water as we pour in.

But it is different for plants growing in soil. Unlike in a pot, not all water that enters the soil returns to the atmosphere. Some of it leaks downward and ultimately returns to the ocean. We cannot see how much water escapes from beneath a particular plant. We can only say that, in a steady state, when the plant is not depleting soil moisture, it transpires less water than the atmosphere delivers as rain.

Now suppose we did our best. We covered the territory in question with multiple rain gauges to measure precipitation P, which, as Bruce Danckwerts reminds us from Zambia, can be very far from spatially uniform. We measured the streamflow of the river draining this territory to estimate runoff R. And we continued these measurements long enough for soil moisture to equilibrate, so that dS/dt = 0.

In this case, we can estimate the average evapotranspiration over the territory from mass conservation, the simple fact that water does not disappear into nowhere:

E = P − R.

Both P and R come with their own uncertainties. For E, which is deduced from P and R, these uncertainties accumulate, making evapotranspiration the least certain of the three estimates.

Some additional constraints, however, come from atmospheric data. This brings us to a peculiar data-model hybrid called reanalysis. Reanalyses play an enormous role in modern environmental research. To judge how robust a given conclusion or prediction is, we need to understand what they are, and what they are not.

The Reanalyses Miracle

As we discussed in Part I, the water budgets of the atmosphere and the ground are tightly linked, but not symmetrically. The atmosphere is a net supplier of moisture to land: it draws water evaporated from the ocean inland and delivers it to the ground as rainfall. The ground is a net loser of moisture: part of the received water runs off under gravity and ultimately returns to the ocean.

Over our territory, we can measure the winds that bring moisture in and the winds that carry moisture away. The difference between the two is the net moisture import into the region, called atmospheric moisture convergence C. In a steady state, this surplus must equal what the ground loses as runoff:

C = R.

One useful feature of wind fields is that they can be constrained by satellite observations, giving us a global picture, including regions where direct runoff measurements are sparse or unavailable. So, when we talk about a region as large and varied as China, we cannot be too choosy. We need to consider the water cycle from both sides and use all available data: from the atmosphere above and from the rivers below.

To combine these many imperfect pieces of evidence, scientists use reanalysis products. A reanalysis gathers diverse observations, combines them with a weather model, adjusts the result toward physical consistency, and places the estimates on a regular grid, usually about one degree latitude and longitude in resolution. It is not a pure observation, and not a free-running model either. It is a data-model hybrid that gives us the best available estimate of many atmospheric variables at each location and time.

Because the optimization criteria for combining observations with the model can vary, different reanalysis products can give different estimates of the same variable. Each product reflects a particular way of blending imperfect observations with physical constraints. Once this blending is done, the end user receives something almost miraculous: a detailed global picture in which wind, temperature, humidity, pressure, rainfall, evaporation, and many other variables are available for almost every place and time.

The underlying uncertainties and mismatches do not disappear, but they are hidden from view. One can download various variables and use them directly in further analysis. This is enormously convenient, but it also means that the assumptions built into the product can quietly travel into later conclusions.

In this sense, using a reanalysis is a little like placing money in a managed fund. You may receive a tidy number at the end, but the choices that produced it, and whether you are comfortable with those choices, are not always clear unless you look carefully.

(For a more specific discussion of different reanalysis products in the context of the soil moisture budget, see “We Are Losing Soil Moisture, Why?)

Assumptions about Re-Greening Impacts

But even if we decide to take reanalysis data at face value, this is not the end of our problems. Suppose our territory has been re-greening for decades, while rainfall, evaporation, runoff, winds, and moisture convergence have all been changing too. Which changes are caused by re-greening itself, and which come from the larger climate system moving in the background?

This is a fundamental question.

A common approach, adopted also by An et al. (2025), whose work we began to discuss in Part I, is to assume that the effect of added vegetation consists of returning more moisture to the atmosphere through enhanced transpiration. We can call this the moisture-recycling approach.

Since transpiring more is precisely what extra vegetation is expected to do, the limitation of this assumption is not immediately obvious. However, this assumption unambiguously predicts reduced runoff when transpiration increases. To see why, let us follow the research scheme of An et al. (2025).

Their analysis starts by defining added evapotranspiration. Each vegetation type is assigned characteristic evapotranspiration values at each time step. So, if grassland is converted to forest, the re-greening effect is calculated as the difference between two estimates: the actual evapotranspiration of the forest and the hypothetical evapotranspiration that the original grassland would have had under the same local conditions.

Thus, the actual evapotranspiration can come from the reanalysis, but the re-greening effect is not simply the observed trend. It is the difference between the new vegetation and a reference version of the old vegetation. Therefore, trends in actual evapotranspiration and in added evapotranspiration need not coincide.

Once this added evapotranspiration is defined, the corresponding change in precipitation is estimated with a moisture-tracking model. In plain language: the model marks the extra moisture released by the new vegetation and follows where it rains out within China.

Now comes the crucial point: some of the extra moisture released by the new vegetation can leave China without raining out there. Therefore, in this framework, the re-greening-related increase in precipitation, ΔPᵣ, cannot exceed the corresponding increase in evapotranspiration, ΔEᵣ:

ΔPᵣ ≤ ΔEᵣ.

Here we recall our water budget equation:

R = P − E.

If re-greening changes precipitation by ΔPᵣ and evapotranspiration by ΔEᵣ, and the latter is larger than, or equal to, the former, then runoff R changes by:

ΔRᵣ = ΔPᵣ − ΔEᵣ ≤ 0.

In other words, in this setting, runoff can never increase.

The added vegetation is assumed to return more water from the ground to the atmosphere. Some of this water may rain out again inside China, but some may leave the country as atmospheric moisture. What is not allowed in this scheme is the opposite effect: re-greening being associated with additional moisture drawn from outside. With that possibility excluded, the water available for runoff can only stay the same or decline.

This result follows from the way the problem has been framed. It is not, by itself, evidence that runoff actually declined in the real world.

This distinction is important. The work of An et al. (2025) was widely understood as referring to actual changes in precipitation ΔP, evapotranspiration ΔE, and water availability or runoff ΔR observed in China during the decades of re-greening. In fact, however, these statements refer to hypothetical changes in these variables, ΔPᵣ, ΔEᵣ, and ΔRᵣ, calculated under the moisture-recycling assumptions described above.

What actually happened in China during these years is a separate question. We will turn to it in the next post.

Re-Greening and Moisture Convergence

Let me now summarize what we have discussed so far with a picture.

The left and right panels show the same air circulation and water cycle, but the landscape is omitted from the right panels for clarity. Fig. 1 from https://arxiv.org/abs/2604.09510

We first consider desert land bordering the ocean and receiving occasional rain (panels a,d). There is no vegetation and no evapotranspiration. All precipitated water drains back to the ocean. Light-blue arrows show the inflow of moist air that rises and generates precipitation. White arrows show dry air, depleted of moisture, leaving the area. The same number of air arrows enters and leaves. Precipitation P is shown by the vertical dark-blue arrow, while runoff (water yield Y) is shown by the slanted dark-blue arrow.

Now we add some vegetation to the landscape, while keeping air circulation unchanged (panels b, e). Transpiration by plants (E) returns some of the precipitated moisture back to the atmosphere, where it can re-precipitate. Thus, precipitation has increased compared to the desert state: the same amount of air rises per unit time, but it is now wetter, so more rain is generated.

However, because the air has become wetter, some moisture now leaves the area with the outgoing low-level air instead of contributing to runoff. Hence, runoff has decreased relative to the desert state, although it can become more stable, as we will discuss below.

Finally, we consider a state in which added vegetation has moistened the atmosphere enough to change its dynamics: more moisture now flows in with the air and rises over the region (panels c, f). There is also more moisture outflow, just as the Amazon forest moistens agricultural regions downwind. But the net moisture transport has increased, and so has runoff.

Compared with both the desert state and the intermediate state, in this biotic-pump regime both precipitation and runoff have increased.

Outlook

I would like to conclude by discussing a few responses to the above arguments, especially those raised in an open-access discussion in the Eco-Restoration Alliance (with insightful comments from Hart Hagan, Judy Schwartz and Neal Spackman, among others). In particular, Didi Pershouse listed several important water-related effects of vegetation (a related point was raised by Rob Lewis in his comment):

Let us discuss these points using the same mass-conservation framework with which we have been following the hydrological cycle in China.

• There is a positive relationship between soil moisture and subsurface runoff. For a given porous structure and landscape slope, the more moisture the soil contains, the more water can leak downward and drain under gravity.

  Dry soils drain little. Wet soils drain more, but they cannot drain more water than the atmosphere delivers. This places an atmospheric limit on how wet the soil can become.

  In the extreme case, imagine a devegetated landscape with dry soil, no infiltration, and 100% surface runoff. Without changes in atmospheric circulation, the maximum possible increase in soil moisture storage is limited by the flow of water that can be shifted from surface to subsurface runoff.

• Both evaporation and transpiration cool the surface from which they occur. Physically, they are essentially the same process: liquid water becomes vapor by consuming energy.

  While reduced evaporation diminishes uncontrolled soil moisture losses from the soil surface, cooling of the surface as a whole means that transpiration and evaporation together (evapotranspiration) have increased compared to the unvegetated state. The cooler and wetter soil sends more moisture to the atmosphere than in the unvegetated state.

• If evapotranspiration has increased, but atmospheric moisture transport has not, runoff must decline. Even in the extreme case where the unvegetated landscape had 100% surface runoff, the restored landscape cannot drain the same amount of water if it now sends more water to the atmosphere. Its total runoff (surface and subsurface) must be lower by the amount of increased evapotranspiration.

In summary:

Long-term mass conservation says nothing about how runoff is partitioned in space and time: whether it comes as irregular, mostly surface runoff following irregular rains, or as steadier drainage from wet soil throughout the year.

One could argue that much of the flashy runoff is lost in any case, while steadier drainage is more useful, even if it is smaller in total. In many cases, this is a valid and important argument. Moreover, from the plants’ perspective, runoff is water that was not used for transpiration. It is an indispensable loss, the price of keeping soil moist. Thus, a reduction in runoff does not necessarily interfere with ecosystem restoration itself. It can be a normal initial stage of recovery.

In other human contexts, however, total runoff matters. For example, a hydropower plant may collect streamflow in a dam and use the stored water to generate electricity. Or a dam may collect water for later irrigation. In such cases, the irregularity of flow may matter less than the total volume of water that arrives. This becomes especially relevant when restoration efforts scale up and their hydrological impact can be felt at the regional level.

The same logic applies to beavers. They slow water down and moisten the soil locally, which can increase vegetation and transpiration, shifting part of the water route from streamflow to the atmosphere. If atmospheric circulation does not change, this will reduce the streamflow that reaches people downstream. There is little point in arguing whether beavers and the associated vegetation “contribute water” to the watershed without explicitly defining what “contributing” means.

There is much confusion around the terms “water availability,” “water yield,” and “runoff,” which I tried to clarify in Part I. How much moisture the soil contains is one variable. How much water an area drains is another. In some cases, they are positively related. In others, they can change in opposite directions. Increased rain is not equivalent to increased runoff. Removing trees that “steal water” at early stages of ecosystem recovery may permanently lock the ecosystem in a desert state. More about that in the next post.

The bottom line is that we cannot understand the water cycle, or its changes, by focusing only on the soil, only on the atmosphere and winds, or only on streamflow. Nor can we communicate this complex subject clearly to our peers without being explicit about these different components. We need to see how they relate to one another, and how vegetation interacts with all of them. This can help avoid unnecessary controversies when navigating the complex landscape of different stakeholder interests and advocating vegetation-mediated water-cycle restoration. It is also essential for my primary concern: the preservation of extant water-competent ecosystems. Simply understanding what the other side means can make our own narrative more accurate and constructive.

If ecological restoration produces a cooler and wetter area that drains more water than it did when devegetated, this means that more moisture has been brought in by the atmosphere. The biotic pump has been activated.

Related reading:

China, which has added vegetation to its land on a massive scale in recent decades, provides a unique setting in which to study these questions.

Image source: NASA

In October 2025, a very interesting study was published in Earth’s Future, a journal of the American Geophysical Union: An et al. (2025) “Land Cover Changes Redistribute China’s Water Resources Through Atmospheric Moisture Recycling”.

This study concluded that the vegetation added in China increased rainfall and evapotranspiration, but reduced the country’s overall water availability. To quote the abstract:

The study was, unsurprisingly, picked up by many news outlets, including Popular Mechanics, Live Science and Earth.com, and seems to have resonated widely. In late 2025 and early 2026, several colleagues from around the world asked me to comment on it. Since the study is directly relevant to the biotic pump concept — which predicts an increase, not a reduction, in water availability on land — we decided to look into the issue more closely.

An unexpected conclusion, which I would like to share in this mini-series of posts, is that the study’s finding of reduced water availability due to added vegetation was effectively predefined by its methodology. In other words, the assessment was framed in such a way that reduced water availability emerged independently of the data, as a built-in consequence of the underlying assumptions.

This unusual situation is a good illustration of just how complex vegetation–hydrology feedbacks really are and, I hope, offers readers an engaging way into the subject, even if it is somewhat dense. To me, there is no better entry into a complex field than through a controversy. While the textbook route can leave one with passive knowledge and the illusion of understanding, analyzing a live controversy keeps the mind alert and prepares it for the task of creating new knowledge.

So let us follow the path of water in China.

The Water Cycle Components and Terminology

We begin with the fundamentals. To understand the water cycle, it helps to look at it from two complementary perspectives: from the ground, where water is received and stored, and from the atmosphere, which delivers it and takes it away.

From the ground perspective, water arrives as precipitation, P. Once it reaches the land, it can follow three paths. It can return to the atmosphere through evaporation and plant transpiration, together called evapotranspiration, E. Second, it can run off under gravity as either surface flow or subsurface runoff or streamflow, R, eventually making its way to the ocean.

Or it can remain on land, accumulating below ground as soil moisture and groundwater. This third pathway is different from the first two. Evapotranspiration and runoff are flows: they move water from one reservoir to another. Storage change is not a flow. It describes what happens when water stays in place and the local moisture store grows or shrinks.

To make this distinction explicit, we denote the storage term in the water budget as dS/dt, where S is the local moisture store. This notation means the rate at which storage changes with time: a small change in storage, dS, over a small interval of time, dt.

These quantities are tied together by the most basic physical law: conservation of matter. Water does not appear from nowhere, and it does not vanish into nowhere. Whatever falls on land as precipitation must do one of three things: return to the atmosphere, leave as runoff, or remain on land by changing storage. This gives the basic water-budget equation:

P = E + R + dS/dt.

Every drop of precipitation must follow one of these paths. It can rise into the air, flow to the sea, or stay and build the hidden reserves of moisture underground.

Water Yield and Water Availability

Let us now clear up a potential source of confusion. In hydrology, runoff R is sometimes referred to as water yield, as in this old hydrological dictionary:

Screenshot from “General Introduction and Hydrologic Definitions” by W. B. Langbein and K. T. Iseri (1960), Manual of Hydrology: Part 1. General Surface-Water Techniques.

The point of this term is to capture all forms of runoff together: surface runoff, subsurface runoff, and streamflow. The dictionary states that water yield is equal to precipitation minus evapotranspiration, R = P - E. But from the water-budget equation above, we can see that this is true only in a steady state, when local water storage does not change and dS/dt = 0.

Here the difference between flows and storage change becomes especially clear. A steady state means that, over the period considered, the local moisture store remains unchanged. Reservoirs may already be full, with no capacity to hold additional incoming moisture. Or rainfall may fail to infiltrate the soil and instead leave entirely as surface runoff, while the soil itself remains persistently dry. In such cases, storage does not change: dS/dt = 0.

A similar simplification often applies over sufficiently long timescales. Since local storage is finite, it cannot continue to influence the water budget indefinitely. Over long enough periods, storage changes usually become small relative to the fluxes, and one can approximately set dS/dt = 0.

So, in a steady state, the transient storage term drops out, while the flows remain. The budget equation becomes simply

P = E + R.

Only in this case is runoff, or water yield, equal to precipitation minus evapotranspiration.

In the general case, however, not all precipitation that is not returned to the atmosphere becomes runoff. Some of it may remain on land, replenishing soil moisture and groundwater, or offsetting an ongoing depletion of these reserves.

Outside steady state, P - E is therefore better understood not as runoff alone, but as water availability in a broader sense. It is the water left on land after evapotranspiration, to be divided between runoff and storage change. This is the definition adopted by An et al. (2025):

Atmospheric Perspective

Let us now look at the same water budget from the atmosphere. Precipitation, which delivers moisture to the ground, removes it from the air. Evapotranspiration does the reverse: it draws water from the ground and returns it to the atmosphere. There is also a third pathway by which the atmosphere gains moisture locally: transport by the winds.

The winds carry only a small amount of moisture, typically less than 1% of air mass. If air simply passes through horizontally, the net import of moisture, also known as atmospheric moisture convergence, is zero. But if that moist air rises and cools, its water vapor condenses and precipitates. The air leaving the region is then drier than the air entering it, and the atmosphere has delivered moisture to the surface.

In this scheme, we view the water cycle from the perspective of the atmosphere. Moist air enters and leaves the region (light blue arrows), while drier air flows out (white arrows): whatever air enters must, in the end, also leave. Evapotranspiration (curved light-green arrows) adds moisture to the atmosphere, while precipitation (the downward blue arrow) removes it.

The local budget of atmospheric moisture M can be written as

dM/dt = E + Fᵢₙ − Fₒᵤₜ − P.

Here Fᵢₙ is the incoming moisture flux and Fₒᵤₜ is the outgoing moisture flux. Their difference,

C = Fᵢₙ − Fₒᵤₜ,

is called atmospheric moisture convergence.

A key point is that the atmosphere can hold only a limited amount of water. At terrestrial temperatures, water vapor condenses readily, so atmospheric moisture storage is necessarily small. Even over tropical oceans, the total atmospheric moisture content — consisting mostly of water vapor, with only minor contributions from cloud water and precipitation water — is only about 40 mm. That is the depth of water that would form if all atmospheric moisture above a given surface area were condensed and brought to the ground.

This is very little. With typical tropical precipitation of about 4–5 mm/day, the entire atmospheric moisture store turns over in just a few days. So when we average over periods longer than about a week, the storage term dM/dt becomes negligible compared with the fluxes themselves.

In that case, the atmospheric water budget simplifies to

P = E + C,

which means that, from the atmospheric point of view, evapotranspiration and moisture convergence are the sources of moisture, while precipitation is the sink.

From the ground perspective, conversely, precipitation supplies moisture to the ground, while evapotranspiration and runoff remove it:

P = E + R.

Here the link between land and atmosphere becomes clear: whatever moisture the atmosphere brings to a location ultimately leaves it as runoff:

C = P - E = R.

Outside steady state, the balance acquires an additional term. Atmospheric moisture convergence then equals water availability:

The Big Measurement Problem: The Visible and the Invisible

By now we have assembled quite a list of key variables, all linked to one another and all potentially altered when vegetation is added to the landscape: precipitation, runoff in its various forms, atmospheric moisture convergence, evaporation and transpiration, and local water storage in soil moisture and groundwater. Atmospheric moisture itself is tiny by comparison and, on timescales of several days or more, remains close to steady state.

What is crucial to keep in mind is that all of these quantities are measured in very different ways. The visible parts of the water cycle, such as precipitation and streamflow, are the easiest to measure. In China, one of the earliest references to precipitation measurement appears in Qin Jiushao’s Mathematical Treatise in Nine Sections, published in 1247. According to Strangeways (2010),

Below is a modern precipitation gauge in Yakutia. Like its older counterparts, it measures precipitation at a single location.

In contrast, runoff is conventionally measured as the streamflow draining a given area. It therefore represents an integrated, rather than local, property of the drainage basin. For example, the Óbidos gauge station on the Amazon River measures streamflow from a drainage area of nearly five million square kilometers. This is done in a relatively straightforward way, by measuring water level and flow velocity. However, such measurements do not account for groundwater outflow from the basin. That component must be treated separately and can only be included through additional assumptions.

To compare such a runoff estimate with precipitation, we would need multiple rain gauges spread across the basin and capable of capturing the rainfall variability that matters for the area average. In modern times, we can also rely on satellite estimates of precipitation, but these, too, are ultimately calibrated against ground-based measurements.

Soil moisture and deeper groundwater present measurement problems of their own. To mention just one, measuring soil moisture along a deep profile corresponding to the rooting zone of large trees may require drilling or boring holes and installing sensors in the soil. But this very act disturbs the local soil and biota, and may itself alter soil moisture.

A sensor for assessing soil moisture. An electromagnetic pulse is sent along metal rods, and its propagation time depends on the water content of the surrounding soil.

The Invisible

But the real difficulties begin when we turn to the invisible parts of the cycle: atmospheric moisture convergence and evapotranspiration.

To estimate atmospheric moisture convergence, we would need to track, with very high accuracy, the velocity and water vapor content of all air masses entering and leaving a given area. This is already a demanding task. Water vapor is only a minor constituent of the atmosphere, and its distribution is highly uneven in space and time. As a result, even when air motion itself is represented reasonably well, the transport of water vapor may still be estimated poorly.

A natural check is to compare atmospheric estimates of moisture convergence with runoff measured independently at the ground (remember, C = R). This check is not always passed. For example, global climate models may describe large-scale circulation reasonably well, yet when their atmospheric moisture convergence is compared with observed runoff in major river basins, substantial discrepancies remain. For the Amazon, the mismatch can reach about 50%.

Data from Hagemann et al. 2011 showing discrepancies between atmospheric moisture convergence and river runoff in some river basins

And yet atmospheric moisture convergence is not the hardest quantity to estimate. After all, it still depends on variables we know, in principle, how to measure: air motion and water vapor concentration.

Evaporation and transpiration are even more elusive.

The reason is simple. They add water vapor to the atmosphere very slowly compared with how quickly winds mix that vapor over space. Consider a small vegetable garden of 100 square meters. Let cumulative evaporation and transpiration be E = 2 mm/day. This means that the garden contributes 200 kg of water vapor to the atmosphere per day, because a water layer 1 mm deep spread over 1 square meter weighs 1 kg.

Now let the mean wind speed be u = 2 m/s, and let the column water vapor content be M = 30 mm, that is, 30 kg/m². For a square garden of area 100 m², the side length is L = 10 m. Under these conditions, the gross atmospheric moisture flow across one side of the garden in one day is M u L = about 52 million kilograms, or 52 thousand tons of water.

The garden contributes 200 kg of water vapor per day, while the moving atmosphere carries 52 thousand tons across it. The local evaporative signal is thus submerged in a vastly larger moving background.

And this mixing interferes in important ways. Suppose, for example, that we want to infer transpiration intensity from the temperature contrast between a transpiring patch, such as the small fir tree in the picture below, and a nearby dry surface. Under clear and windless conditions, such a contrast can become very large, reaching several tens of degrees Celsius. But in cloudy or windy weather, it is smoothed by atmospheric mixing. How strongly it is smoothed depends not only on wind speed, but also on season, surface roughness, and other factors that are rarely known with sufficient precision.

Local cooling from plant transpiration. With incoming solar radiation of about 1 kW m⁻², dry area on the deforested plot (left) has temperature of 55.3°C. Young transpiring trees (right) lower the surface temperature by almost 30°C. Distance between the two spots is 1 m. Measurements and photo credit Jan Pokorný.

For this reason, local estimates of evaporation and transpiration can be highly uncertain and heavily dependent on parameterization. I often cite the study by Teuling (2018), who pointed out a striking example. When transpiration is estimated from flux towers, that is, from local measurements of water vapor concentrations and turbulent transport (the atmospheric perspective), one may conclude that grasslands transpire more than forests. But when transpiration is estimated at larger scales from the ground-based water budget, as precipitation minus runoff, the conclusion is reversed: forests transpire more than grasslands.

This gives some sense of the conceptual and practical difficulty of measuring this invisible, yet fundamentally important, part of the water cycle.

What We Have Discussed in Part I

• On the ground, precipitation is partitioned between evapotranspiration, runoff, and local moisture storage:

  P = E + R + dS/dt.

• In the atmosphere, precipitation is partitioned between evapotranspiration and atmospheric moisture convergence:
  P = E + C.

• In a steady-state,
  R = C.

• All of these variables can, with varying difficulty, be measured independently. But when we combine them as mass conservation requires, gross mismatches often appear.

• Evaporation and, especially, transpiration are the hardest to measure, because their signal must be extracted against strong atmospheric mixing. In practice, the most reliable estimate comes from the ground-based water budget: from known precipitation and runoff.

In the next part, we will look at how plant impacts on the water cycle can be studied under these conditions — and how built-in assumptions can drastically alter the outcome of the analysis. Please stay tuned. In the meantime, your comments are very welcome.

Also, please note that tomorrow, Saturday, 18 April 2026, from 10:00 a.m. to 12:00 noon ET, I will take part in the online mini-conference “Protect and Restore Ecosystems to Cool the Climate” , organized by our great friends at Biodiversity for a Livable Climate. The event is free and will include a discussion. You are very welcome to register and join.

The Australian Monsoon Enigma

The first insightful commentary comes from Jane Morton, as communicated by David Maher from Rehydrate Earth, Australia, who also did the literature compilation:

I would like to say how highly I value your work. It seems to me that the concept of the biotic pump is one of the most important scientific insights for explaining climate and the functioning of ecosystems, and I try, whenever possible, to introduce Australian scientists and members of the climate movement to it. I also follow closely the research on the possible direct cooling effect of forests.

I would like to note one small point that may be more about the way it is presented than about the substance itself. In several of your talks you refer to the Johnson et al. (1999) study on emu eggshells as evidence of a dramatic change in vegetation in Australia. For example, this appears at about the 44-minute mark in this talk.

The difficulty I encounter when discussing your work here is that this particular study is debated within palaeoecology, and in Australia it can also be politically sensitive, since it is sometimes interpreted as claiming that traditional Aboriginal land-management practices led to ecological collapse.

As a result, critics sometimes focus specifically on this reference rather than discussing the much stronger aspects of your argument concerning the connections between vegetation and precipitation and the associated atmospheric dynamics. In practice this often becomes an unnecessary distraction.

I may be mistaken, but it seems to me that the central point you are making does not actually depend on this particular study, since there is now a substantial body of evidence showing that vegetation has a strong influence on precipitation and atmospheric circulation.

Here is a short note reviewing part of the relevant literature — it may possibly be useful:

https://docs.google.com/document/d/1IczPzeg8Ptc67GjygftaIYGXy7RT7iFB/edit?usp=drivesdk&ouid=114682885048490279765&rtpof=true&sd=true

If you have the time, I would be very interested to hear your thoughts on this, because I try to represent your work as accurately as possible when discussing it with people here.

In any case, thank you again for the outstanding work you have done on this topic. I consider these ideas extremely important and try to help ensure that they are taken seriously here in Australia.

Thank you very much for your kind words and interest in our work!

I want to explain first why possible human links to Australian drying matter. The biotic pump concept proposes that natural vegetation can strengthen the terrestrial water cycle by drawing atmospheric moisture inland from the ocean. If so, the disappearance or recovery of natural vegetation, together with the associated changes in rainfall and runoff, can serve as a real-world test of the theory. But such a test is only clean when these changes are not entangled with a larger geophysical shift in climate. Otherwise, it becomes hard to tell what is biotic and what is geophysical.

Evidence in support of the biotic pump comes from three main cases where these influences can, to a substantial degree, be told apart. The first is the Amazon rainforest. The Amazon appears to set up its own rainy season well before favorable geophysical conditions arrive, that is, before the Intertropical Convergence Zone reaches the region. Because the ocean covers most of Earth and supplies most evaporation, the near-equatorial rainfall belt normally follows the Sun from one hemisphere to the other. But the Amazon moves earlier. By producing new leaves, intensifying transpiration, and moistening the air, it starts drawing moisture inland ahead of the expected seasonal schedule. You can read more about these processes and their study in The Amazon's Seasonal Secret from NASA.

Meridional distribution of zonal winds, vertical air motion in the major circulation cells (Hadley, Ferrel, and Polar), sea level pressure, and precipitation. The seasonally shifting geophysical precipitation peak associated with the Intertropical Convergence Zone is highlighted in yellow. Source: Makarieva and Gorshkov 2015.

The second line of evidence comes from the Eurasian boreal forest, a remarkable forest belt about seven thousand kilometers long. Its strong seasonality allows us to compare moisture transport when the forest is active with moisture transport when it is dormant, again helping separate biotic effects from geophysical ones. When the forest is dormant, precipitation and runoff fall off sharply from west to east. When it is active, strong inland moisture transport feeds the great Siberian rivers.

The Australian example is another important case in this sequence. Much of the Australian continent lies within the geophysical downwelling zone of the Hadley and Ferrel circulation cells (see the scheme above). Descending air warms and suppresses rainfall. For rain to form, air must rise, allowing the water vapor it contains to cool and condense. These geophysical conditions place important limits on what vegetation can achieve in facilitating the water cycle.

In other words, Australia is a geophysically difficult continent. Ecosystems there must work especially hard to sustain, so to speak, the biotic pump. Conversely, the threshold of stability is lower than in more favorable regions, so the system is more easily disrupted.

It is therefore unsurprising that Australia has experienced repeated periods of wetting and drying in response to large-scale climatic shifts, as shown, for example, by studies of changing water abundance in Lake Eyre. What is remarkable, however, is that after the arrival of the first humans around 50 thousand years ago, drying set in, and the monsoon that had delivered moisture inland never recovered, despite subsequently more favorable geophysical conditions.

Let us take a look at these data from Magee et al. 2004 “Continuous 150 k.y. monsoon record from Lake Eyre, Australia: Insolation-forcing implications and unexpected Holocene failure”:

Figure 3 of Magee et al. 2004. Lake Eyre record of lake level (from Fig. 2), lake area, and lake volume (DeVogel et al., 2004) as proxy for Australian monsoon compared with sea level (Lambeck and Chappell, 2001) and variations in January insolation for 50°N and 20°S (Berger and Loutre, 1991) over past 150 k.y. Playa-floor deflation events, indicative of significant aridity and therefore reduced Australian monsoon, are included only where there is stratigraphic or sedimentologic evidence for deflation. AHD—Australian height datum (mean sea level).

The researchers consider whether the wetter and drier periods can be linked to changes in insolation, but ultimately conclude as follows (with my emphasis):

Regardless of which hemisphere’s insolation exerts the strongest control, the early Holocene phase I lake level was strikingly lower than the levels achieved early in the last interglacial, when sea level and insolation forcing were similar. This contrast is further enhanced by comparison with the last significant lacustrine event, which was related to more effective penetration of monsoon moisture into the continental interior at 65–60 ka (phase III, at 23.5 m relative to AHD), when sea level was much lower and astronomic forcing less favorable than in the Holocene in both hemispheres (Fig. 3). …

There is abundant evidence of substantial reinvigoration of the planetary monsoon in the early Holocene from outside Australia (Carmouze and Lemoalle, 1983; Hoelzmann et al., 2000; Liu and Ding, 1998; Rousseau et al., 2000; Wasson, 1995; Williams et al., 2000) and coeval reactivation of the monsoon along the northern Australian fringe (Nanson et al., 1991; Nott and Price, 1994). We attribute the failure of the Holocene monsoon to penetrate into the Australian interior, as it had done as recently as 65–60 ka, to be related to a change in boundary conditions over the Australian landmass. Decreasing the transfer of moisture from the biosphere to the atmosphere during the monsoon season would inhibit the penetration of monsoon rainfall into the Lake Eyre catchment. A plausible boundary-condition change that could affect the efficiency of landward transfer of monsoon moisture is the large-scale alteration of the biota—by human burning—across the northern half of the continent, as suggested by Johnson et al. (1999) from vegetation changes recorded in the carbon isotopic signature of emu eggshells. However, Kershaw et al. (2003) argued that MIS 3 continent-wide vegetation changes, seen in marine core pollen records, occurred slightly later than reported by Johnson et al. (1999) [we discussed this paper in “What’s Happening with Global Precipitation?” — AM], and may have a more complex cause.

In summary,

Regardless of the hemispheric forcing, the low intensity of the early Holocene Australian monsoon—by comparison with the last interglacial and particularly the last high-level lacustrine event at 65–60 ka when all forcing elements were modest—is an enigma that can be explained by a change in boundary conditions within Australia.

The biotic pump concept can explain this and similar enigmas by showing that, under the same large-scale climatic forcing, drastically different continental water cycles can arise depending on the state of the terrestrial biota.

The Human Controversy

The biotic pump concept can also help address some of the main arguments against the idea that the first humans disrupted native vegetation in Australia and thereby triggered a tipping point that shifted the continent into a much drier state, perhaps irreversibly.

Mooney et al. 2011 in “Late Quaternary fire regimes of Australasia” provide a summary of such arguments as follows (with my emphasis):

The influence of humans in modifying natural fire regimes has been a major feature of the interpretation of charcoal records from the Australasian region. The apparent coincidence of increases in sedimentary charcoal at iconic sites (Lake George, Lynch’s Crater, Darwin Crater) with the arrival of Aboriginal people in Australia, has been attributed to anthropogenic fire (e.g. see Turney et al., 2004). This has led to circular arguments about the relationship between fire and people, including assertions that people arrived on the continent before the last glacial (Jackson, 1999; Singh et al., 1981). Changes in vegetation cover driven by anthropogenic modification of fire regimes have been explicitly invoked as a mechanism for causing aridification of Australia over the past 50-60 ka and for megafaunal extinctions (Miller et al., 2005). This causal association of anthropogenic fire with changes in climate, vegetation or fauna has remained seductive, despite several lines of contrary evidence. This evidence includes major changes in Late Quaternary charcoal records and hence fire prior to the arrival of humans (e.g. ca 130 ka: Singh et al., 1981; Dodson et al., 2005); the fact that a broadly-synchronous transition to more xerophytic vegetation has been found in New Caledonia, a region which was not settled by humans until ca 3000 years ago (Stevenson and Hope, 2005); and modeling evidence that the purported changes in vegetation cover were insufficient to cause a sustained change in Australasian climate (Pitman and Hesse, 2007). We have found no evidence of a change in fire regimes at a continental scale at the time of Aboriginal colonisation of Australia (50 +- 10 ka).

We first note that the fact that fire regimes can be influenced by factors other than humans does not mean that humans cannot have caused particular shifts in those regimes. More importantly, the first humans did not have to burn much of the continent to disrupt its hydrology. Plausibly, upon arrival they settled along the coast and burned only a relatively narrow strip, perhaps 100–200 km inland from the shore.

Kershaw et al. 2003 in “Causes and consequences of long-term climatic variability on the Australian continent” wrote referring to the study of Johnson et al. 1999 (my emphasis):

They further suggest that the opening up of the vegetation through aboriginal burning resulted in reduced moisture interactions between atmosphere and vegetation and consequently a decrease in effectiveness of summer monsoon penetration into the centre of Australia.
This model is effective in explaining why water was more abundant in the interior of Australia during interglacials previous to the Holocene, and may provide a more comprehensive explanation for sustained changes in the Core GC-17 record [a progressive decline of tree species — AM]. However, Core GC-17 is recording changes in coastal rather than inland vegetation, so that the influence of vegetation on inland penetration of the monsoon is not a factor.

This supports the idea that coastal vegetation was disrupted. This alone could have interrupted the moisture flow supporting the remaining inland vegetation, causing dieback without further burning, simply through increased aridity.

Once the continent as a whole ceased to act as a moisture convergence zone, this aridity effect could have spread over distances comparable to the size of the continent itself, perhaps reaching even New Caledonia.

Regarding the argument that models do not show a substantial change in monsoon strength following land-cover change, we note that Pitman and Hesse (2007) already emphasized in the abstract of their study, “The significance of large-scale land cover change on the Australian palaeomonsoon,” that

the limitations implicit in our analytical methods means we cannot conclusively demonstrate that biospheric feedbacks can be ignored.

In “Forests, Water, and Climate: Time for Re-Conceptualization,” I discussed related evidence suggesting that models do not robustly capture changes in air circulation and moisture transport associated with land-cover change.

Furthermore, a very interesting exchange in PNAS in 2016 between German and American researchers concluded that global climate models cannot simulate abrupt changes in monsoon systems unless the forcing changes abruptly as well, and that vegetation feedbacks may be one possible explanation for such abrupt monsoon shifts.

With this, we are now moving from Australia to North America.

Biotic Pump and the Shortgrass Prairie

A while ago, I received two independent but related questions at nearly the same time. One was from Libby Comeaux:

I’m wondering how to evaluate the difference the Rocky Mountain Continental Divide may make, as we have coniferous-dominated forests on the Pacific Ocean side on the West, and on the large land-mass side on the East. I live on the shortgrass prairie ecosystem immediately east of the mountains. Early spring warming - even before late spring snows - can send snow melt down to the shortgrass prairie before farmers can use it, then it runs down streets and pipes to reservoirs too soon. (Of course, much better to soak into healthy soils; we have much work to do) My question is whether biotic pump functions on the slope down from the Continental Divide on the East.

The other was submitted privately:

Hi Anastassia, I have a question about the biotic pump applied to North America. I am curious about the forest dynamics of North America and have been reading “Long-Term Forest Dynamics of the Temperate Zone” by Delcourt and Delcourt to find out how much forest really was here after the glaciers receded and before man intervened (beginning with indigenous people extirpating megafauna and burning the land). Their analysis indicates that at 14,000 ybp the glacier had receded significantly and North America was dominated by boreal forest and mixed deciduous farther south. By 10,000 ybp, the center of the plains had already begun to convert to praire. Now presumably, at 14,000 ybp the same drying of the pacific airmass as it came over the western mountains would have been happening, but the boreal forest was kept intact across the country, maybe thanks to the biotic pump. So there are two questions: First, in this case of the pacific airmass losing its moisture as it goes up and over the mountains - could the action of the biotic pump have counteracted this drying effect? Second - if the biotic pump was counteracting that, then why did the prairie region encroach? I imagine this could have happened as a result of humans degrading the ecosystem with the above mentioned disturbances. Thank you for your time and all of your incredible work that you have done for our understanding of nature.

Let us take a look at those maps in the book “Long-Term Forest Dynamics of the Temperate Zone: A Case Study of Late-Quaternary Forests in Eastern North America” by Paul A. Delcourt and Hazel R. Delcourt, published by Springer in 1987.

We can see that in the late glacial interval there was no prairie, but the whole region was covered by forests: BF, boreal forest; MF, mixed conifer-northern hardwoods forest; DF, deciduous forest; SE, southeastern evergreen forest; SS, sand dune scrab. The prairie (P) appeared four thousand later.

So we are left with two questions. First, could tree cover exist where prairie now dominates under the same climatic conditions? Second, does modern prairie vegetation itself, at least to some extent, enhance moisture convergence into the region?

The main geophysical obstacle to moisture convergence is the mountain ridge in the west, standing in the path of the westerlies associated with the Ferrel cell. Yet if the ridge is about 2.5–3 km high, depending on surface temperature, the air can still retain roughly half of its original moisture as it crosses the mountains and descends on the other side. In other words, the moist air rises and rains out, but not completely.

Fig. 2A from Makarieva et al. (2013), showing the fraction of moisture remaining in air at height z relative to its surface value (z = 0) for different surface temperatures. Even at 3 km, a substantial amount of moisture remains in the air.

As this air, only partially depleted of moisture, descends east of the ridge, local vegetation can enrich it with moisture again. This may trigger deep convection, causing the remaining moisture to precipitate locally instead of being blown farther away.

Over land, most rainfall is produced by a relatively small number of strong convective events. According to Liu and Zipser (2015), in “The global distribution of largest, deepest, and most intense precipitation systems,” more than 70% of land precipitation is associated with convective systems whose precipitation columns extend above 7 km. One mechanism by which local vegetation could therefore enhance moisture convergence is by moistening the air sufficiently to trigger local convection.

Delcourt and Delcourt propose the following air-circulation pattern for the period when the region was forest-covered, and for the subsequent period when prairie was present:

Here PA is Pacific Airmass, PFZ is Polar Frontal Zone, MTA is Maritime Tropical Airmass and AA is Arctic Airmass.

Conceivably, the region with stronger convection could also attract greater low-level air convergence from surrounding regions, specifically from the Maritime Tropical airmass (see also this discussion).

To conclude, the answer to both questions is likely yes. The present vegetation probably does not make the situation worse than it would be in its complete absence, while allowing tree vegetation to restore itself in the region, or assisting its recovery, could plausibly shift the region toward a substantially wetter regime.

Ideological Dimension and Outlook

Unfortunately, it is difficult to keep ideology entirely out of scientific narratives. So I understand why the idea that the first humans may have trapped Australia in a dry regime by burning vegetation can feel uncomfortable.

Interestingly, the ideological twist takes a different form in the other hemisphere, in North America. In Australia, the narrative becomes sensitive when the first settlers are, so to speak, accused of excessive burning. In North America, by contrast, Indigenous people are sometimes portrayed as having burned landscapes on a massive scale, and this is presented almost as a model of careful land stewardship. Very unfortunately, such portrayals are then used to justify commercial forest burning and logging.

However, the more careful evidence does not support the idea of extensive burning by Indigenous people. See, for example, Kellett et al. 2023 “Forest-clearing to create early-successional habitats: Questionable benefits, significant costs”).

Generally, I do not think we should give in to a rather primitive form of ideologization, as if this would somehow cast the first humans in a morally negative light. Having arrived in Australia from very different environments, they could hardly have been expected to know in advance how vulnerable its ecosystems were. It is entirely plausible that they disrupted them before such understanding could exist.

Moreover, the idea that humans pushed the landscape into a dry regime by disrupting vegetation also carries a more hopeful implication. It suggests that if native vegetation were allowed to recover, possibly with assistance from modern humans, a much wetter regime might again become physically possible under the same large-scale climatic conditions. If, on the other hand, past changes were not due to humans, there leaves us little agency now.

The image shows the initiation of ecosystem recovery with native tree seedlings in southern Australia (photo by a friend).

Many modern landscapes are degraded to such an extent that ecological succession can no longer begin on its own, because the genetic information needed for recovery — contained in seeds — is missing. In such cases, humans could play a positive ecological role by restoring the missing flow of seeds and ecological information, until the ecosystem regains the capacity for further self-recovery.

Related reading:

In Canada, where I have never been, there are also many forests. Thorsten Arnold, writing from Canada, has published a new post inviting us to reconsider our local relationships. He highlights the importance of embracing disagreements with those around us — relatives, neighbors, community members. To embrace disagreement is itself a kind of celebration: a sign that relationships are durable enough to contain it. It is normal to disagree on some things while still agreeing on the shared need to persist together, from the past into the future, in this endless dance of life. After all, we are all passengers on the same train called the present.

Disagreements should be celebrated, because just as the shadows in a pine forest testify to the sunshine above the canopy, our disagreements testify to a shared existence and a deeper agreement about the priority of persistence. Questioning that priority is the prerogative of psychopaths, and such tendencies should be kept in check. Everyone else is free to disagree about how persistence is to be arranged.

These are my thoughts beneath the blue sky above the boreal forest, as boreal spring arrives. Skiing is now in the past, and it is time to welcome the birds building new homes.

A Dual Perspective on Disagreement

Disagreement should not polarize. When it does, the problem lies not in disagreement itself, but in the fading of a more general agreement about the importance of persistence.

Recently, I was struck by the wide range of possible views on the nature of disagreement itself. I listened to two interviews with two very well-meaning people. One explored how a minority can withstand propaganda that seeks to eliminate dissent, even under life-threatening conditions (I discussed it in “Nature’s Complexity and Human Morality”). The other explored how to confront the merchants of doubt, who obstruct the spread of important, scientifically validated information through society.

In both interviews, there was mention of a small hardcore minority of the order of ten percent. But the connotations are opposite. In the first narrative, this minority is the protagonist: it retains independent judgment, does not yield to propaganda, and may even prevent totalitarianism from taking hold. In the second narrative, this minority is cast as deserving ridicule: it remains deaf to any arguments in favor of important, scientifically validated information.

What struck me is how easy it is to reverse the good and the bad in the two narratives. Where propaganda seeks to eliminate dissent, one strategy may be to label independent thinkers as merchants of doubt and fake experts. Conversely, raising one’s voice against a common cause backed by the majority may, in some cases, reflect less a search for truth than an egoistic desire for visibility.

I cannot think of any simple formal criterion that would always distinguish destructive from constructive behavior pursued under the same agenda in some general hypothetical case. But in science, the situation seems much clearer to me. Disagreement is indispensable, and when it is mishandled, science cannot move forward. Science is the work of revealing what is new, and what is new is not immediately evident to everyone. The non-zero inertia of scientific thinking is itself proof that disagreement is necessary.

One may ask: disagreement about what? Some truths are apparently more firmly established than others. At a certain point, academies cease to entertain projects on perpetuum mobile. Other topics are admittedly less well studied, and it is here, I believe, that informed disagreement must be nurtured. Again, if it is not, science will not move forward.

Precipitation Mass Sink on the Move

This is the third part of this story (#1 is here, #2 is here). It describes our recent attempt to open a discussion of the role of the precipitation mass sink in generating the pressure gradients that drive hurricane winds.

To do so, we submitted a commentary to the Journal of the Atmospheric Sciences, which had published a paper that attempted to build a theory of storms while neglecting the mass sink altogether. Using empirical evidence on hurricane rainfall, we showed that this contribution to the central pressure tendency is substantial and cannot be neglected.

The authors of the criticized paper initially agreed to respond, but later chose not to. The commentary was then reviewed by three referees and rejected for publication. All referee reports, along with the preceding correspondence with the journal, are included in the Appendix to this arXiv preprint.

Below is our most recent exchange with the journal, including an appeal to the Publication Commission of the American Meteorological Society. These documents, and their timing, are largely self-explanatory.

Date: 28 January 2026

To:
Dr. Daniel Stern, Handling Editor
Dr. Zhuo Wang, Editor in Chief
Journal of the Atmospheric Sciences
Subject: Editorial action regarding Sparks and Toumi (2022)

Dear Dr. Stern and Dr. Wang,

We write concerning our Comment on Sparks and Toumi (2022), which identifies an unjustified omission of the precipitation term from the pressure-tendency equation. We are grateful to the reviewers for their careful evaluation.

One reviewer stated explicitly that the criticism is valid. A second reviewer characterized it as potentially valid but did not address its substance, instead suggesting development of a standalone paper with a new theory. A third reviewer noted that the model of Sparks and Toumi (2022) would be valid if total air density were replaced by dry-air density, acknowledging that this should be noted. Importantly, none of the reviewers refuted our central claim that, as currently formulated, the model is not valid.

While we respect the editorial decision, we are concerned that the present outcome [i.e., with our commentary rejected — AM] leaves an acknowledged inconsistency unaddressed. In its published form, the model does not specify dry-air density in the governing equations.

Although total air density and dry-air density differ by only about one percent, the key diagnostic quantity—the column-mean velocity—can differ by more than 100% and even change sign depending on which density is used. This is therefore not a minor issue. Moreover, while the equations could in principle be reinterpreted, the numerical analyses cannot be retroactively corrected: they necessarily used either total air density or dry-air density, and this choice must be made explicit.

In our view, if total air density was used, publication of our Comment would be the appropriate mechanism to clarify the issue for readers. If dry-air density was used, a corrigendum would be required. In either case, leaving the matter unresolved does not seem consistent with AMS standards of scientific rigor and self-correction.

We therefore respectfully ask that the journal either reconsider publication of our revised Comment, which addresses all reviewer comments, or request that the authors of Sparks and Toumi (2022) publish a corrigendum clarifying the formulation.

Thank you for your time and consideration. We look forward to your response.

Yours sincerely,

Anastassia Makarieva

Feb 03, 2026
Ref.: JAS-D-26-0022

Dear Dr. Makarieva,

Thank you for submitting your manuscript "Comments on "A Physical Model of Tropical Cyclone Central Pressure Filling at Landfall" by Sparks and Toumi" to the Journal of the Atmospheric Sciences. I am sorry to inform you that this comment is rejected because it falls outside the two-year limit we have set for submissions. You may consider expanding this comment into a full article. In that case, please note that the article must be broad enough in scope rather than solely focusing on a previously published paper.

Thank you for your interest in Journal of the Atmospheric Sciences. Please contact me at ZWang.JAS@ametsoc.org if you have any questions. We wish you a more positive result with future endeavors.

Best regards,

Zhuo Wang, Ph.D.
Editor in Chief
Journal of the Atmospheric Sciences

February 24, 2026

Dear Members of the AMS Publications Commission,

We appeal the decision to reject our Comment (JAS-D-24-0178) on Sparks and Toumi (2022) on the basis of the two-year submission limit.

Our initial submission was made within the two-year period specified for Comments and was processed under the formal Comment–Reply procedure, including invitation of a Reply from the corresponding author of the original paper. The manuscript subsequently underwent external review. The reviews did not refute the central methodological point raised, and one reviewer characterized the topic as underexplored.

The issue addressed in our Comment concerns the treatment of precipitation in the pressure-tendency equation and its consistency with conservation laws. When mass conservation is written for total air, omission of the precipitation term alters the resulting expression, whereas the formulation is internally consistent if written for dry air. In this context, replacing total-air density with dry-air density can materially affect the magnitude and, in some cases, the sign of the key diagnostic variables. Explicit clarification of the density definition in the published formulation would therefore enhance transparency and reproducibility in the scientific record.

AMS policy states that the two-year limit for Comments may be waived at the discretion of the Chief Editor. It also provides that when convincing evidence is presented that the main substance or conclusions of a published paper may be erroneous, the Editor should facilitate publication of an appropriate paper identifying and, if possible, correcting the issue.

We recognize that editorial discretion is central to maintaining consistent standards. At the same time, facilitating open discussion of issues concerning the formulation of governing equations and their consistency with conservation laws serves the interests of the scientific community, particularly when expert views may reasonably differ and the topic has been described as underexplored.

Our purpose in submitting this appeal is not to challenge editorial authority, but to request consideration of whether publication of the Comment — or otherwise facilitating clarification within the published record — would best serve the principle of open scientific exchange in this instance.

We appreciate your consideration.

Sincerely,

Anastassia Makarieva

Andrei Nefiodov

February 26, 2026

Dear Drs. Makarieva and Nefiodov:

Thank you for your correspondence of 24 February 2026 regarding your submitted comment (JAS-D-24-0178).

Journal of the Atmospheric Sciences chief editor, Dr. Zhuo Wang, rejected your comment for publication, on the grounds that more than two years had elapsed since the publication of the original paper (Sparks and Toumi, 2022) on which it comments. You argue, in your message, that your original comment was submitted within the two-year window, so that Dr. Wang’s decision is in error.

I note, however, that this original comment and a subsequent one were rejected for publication following peer review. It is the policy of the American Meteorological Society that a resubmitted rejected manuscript is treated as a new submission. Therefore, the appropriate submission date for your comment is 27 January, 2026, which falls outside the two-year window from the publication of the Sparks and Toumi paper.

I find, therefore, that Dr. Wang was correct in her decision, and her rejection of your comment stands.

Yours truly,

Walter Robinson

Publications Commissioner of the American Meteorological Society

--
Prof. Walter A. Robinson | he/him/his

Chair of the NC State Faculty

Department of Marine, Earth, and Atmospheric Sciences

North Carolina State University

Campus Box 8208

Raleigh, NC 27695-8208

[to be continued]

Outlook

I am sometimes asked why progress on the biotic pump has been slow. But over time I have come to think that it is not unusually slow. Rather, it appears to follow a pattern that is quite normal in atmospheric science: conceptually new ideas may be noticed relatively quickly, but often take decades to influence the field.

Let me offer one conspicuous example. In his famous 1903 paper on storm energetics, Dr. Max Margules introduced the notion of available energy — the part of the total energy that can actually be converted into the kinetic energy of a storm. This amount is much smaller than the total energy, that is, the sum of potential and internal energy.

Yet it was only with Lorenz in 1955, fifty-two years after Margules, that this idea was formulated for the atmosphere as a whole in terms of available potential energy, a concept that is now standard in textbooks. Only then did it begin to be actively discussed and explored.

Let us look at how Lorenz introduced available potential energy:

Consider first an atmosphere whose density stratification is everywhere horizontal. In this case, although total potential energy is plentiful, none at all is available for conversion into kinetic energy. Next suppose that a horizontally stratified atmosphere becomes heated in a restricted region. This heating adds total potential energy to the system, and also disturbs the stratification, thus creating horizontal pressure forces which may convert total potential energy into kinetic energy.

But next suppose that a horizontally stratified atmosphere becomes cooled rather than heated. The cooling removes total potential energy from the system, but it still disturbs the stratification, thus creating horizontal pressure forces which may convert total potential energy into kinetic energy. Evidently removal of energy is sometimes as effective as addition of energy in making more energy available.

Black lines show isobars, that is, surfaces of equal pressure, with pressure decreasing with height. When an air column is locally warmed, it expands upward, increasing air pressure at every height except at the surface. Local cooling produces the opposite effect.

What Lorenz is saying here is that available potential energy arises whenever a pressure gradient (the “horizontal pressure forces”) is created that can set air in motion. Since air pressure depends on temperature, if the atmosphere is initially horizontally uniform in temperature, then either a local increase or a local decrease in temperature will create a pressure gradient and thus the capacity to generate kinetic energy.

Exactly the same argument that Lorenz makes for temperature can be made for evaporation and precipitation, which add and remove gas from the atmosphere and thus also generate horizontal pressure forces. Strikingly, however, this argument has never been developed in comparable terms.

Because the atmosphere is approximately hydrostatic, surface pressure reflects the amount of gas in the overlying column. Thus, unlike warming and cooling that predominantly perturb the upper atmosphere, precipitation creates horizontal pressure forces mainly in the lower atmosphere, where friction is strong and convergence, that is, cross-isobaric flow, is most readily established.

The first biotic pump paper, outlining the first contours of condensation-induced atmospheric dynamics, appeared in 2007, fifty-two years after Lorenz’s 1955 paper and twice that long after Margules’ 1903 paper. So if, as we still hope, real progress is made before 2059, another fifty-two years later, that could still count as normal by the standards of atmospheric science. Whether progress unfolds more slowly or more rapidly will depend, among other things, on how constructive disagreements are handled — and on whether we all persist together until that time.

Related reading:

Besides energy, there is also the problem of the biosphere being destroyed before our eyes — here, too, there is a wide spectrum of opinions even among well meaning people, from things are totally fine and the biosphere is re-greening, to human ingenuity will fix it provided sufficient financial incentive, to stop the destruction and let nature space to breathe.

People arguing for some form of diminishing human activity are naturally the least optimistic, since they are trying to assess the limits that nature has placed on what human ingenuity can realistically achieve. Interestingly, when it comes to the question of “what to do,” increasingly common advice is to “go local”: for example, become a carpenter or learn other practical skills. Two recent interviews in the Great Simplification podcast—with Balázs Matics and Craig Tindale—end with essentially the same advice to listeners. The latest Frankly also concluded that now is the time to put stones in the river (presumably to slow the water). The more optimistic human-ingenuity group, on the other hand, tends to advocate grand and ambitious projects.

Of course, if everything crashes, people with practical skills and strong local connections are likely to endure the crisis relatively better (whatever “better” might mean then). However, focusing strategically on individual and local survival—and letting the larger dynamics (sometimes loosely referred to as “self-organization”) take care of themselves—is precisely what brought us to the current state in the first place.

Instead of giving up too early and alienating ourselves from one another even further as we regain a local focus, I would like to suggest that we still have an opportunity, at least, to discuss what kind of human civilization could remain stable under natural limits, without continually generating existential problems that must then be solved—successfully or not—by ingenuity. From my perspective, it would be a major fiasco simply to start a new cycle of “being local — going global — collapsing” without even having found a theoretical solution for how we might organize our existence in a better and more stable way—if such a solution exists at all.

As an early disclaimer, I myself think that we do need to become more local, in the sense that we should grow more food where we are. (My personal dilemma, which has its global counterpart, is that on our small plot of land a natural forest has been allowed to regrow, so clearing space for vegetables would mean cutting trees, something that I hope is not going to happen while I am alive.)

Helping friends to harvest potatoes (Siberia, the Yenisey river)

What I am arguing against is localization as a global strategy. Besides being intellectually unsatisfactory, it would not work: being well off amid mass starvation is not safe. Now that we are all in one boat, it is in our common interest that nobody be driven to such despair as to destroy the boat for everyone. This requires an increased global coordination and mutual understanding.

My persistent motivation is to share several insights that emerge from the concept of biotic regulation, which, despite its high relevance to today’s problems, remains little known. In today’s post, I will discuss the problem of inequality in a biospheric context.

Energy Consumption and Increasing Size

The cause of the current predicament is often attributed to the genetic hardware that shapes human behavior, in which context the Maximum Power Principle is often invoked.

While there is much discussion in the literature about what this principle could actually mean in a biospheric context (see, e.g., Sciubba 2011 “What did Lotka really say?”), its common interpretation is that a system that utilizes more power tends to prevail over one that utilizes less power, and that natural selection favors the former.

Since larger systems generally utilize more power, there should be a corresponding tendency for larger, internally correlated systems to prevail. The way competitive capacity can increase aggressively with size and correlation was vividly described by the Russian poet Vladimir Mayakovsky:

One man alone

feels down and out.

One man alone

won’t make weather.

Any old bully

can knock him about -

even weaklings

if two together.

But when

we midgets

in a Party stand -

surrender,

enemy,

fade

out of sight!

A Party’s

a million-fingered hand

clenched

into one fist

of shattering might.

These words were written about a century ago in revolutionary Russia, but in the modern context “Party” can be replaced, for example, by “Corporation” or “Monopoly,” or, if one wants a more positive connotation, by “Trade Union.”

What matters is that this type of spontaneous development, if it were universally supported by natural selection and facing no structural constraints, could lead to a single large internally correlated structure occupying all available space and claiming all energy flows. This seems to have occurred in the case of global human civilization, which now represents a rigidly correlated entity—the Superorganism—with no external rivals left to compete with.

Once previously competing units become tightly interdependent within a single structure, their residual competition becomes pathological, taking on the meaning—and the destructive effect—of an autoimmune disorder.

Detachment from Reality Associated with Size

So, if greater power consumption translates into higher competitive capacity, and larger size translates into greater power consumption, we end up with a small number of large, internally correlated energy consumers.

As an entity grows larger, its surface-to-volume ratio declines, effectively decoupling most of it from the external environment. In a multicellular body, for example, the proportion of cells directly bordering the environment is roughly equal to the ratio of the linear size of a cell to the linear size of the body. Thus, for a mammal with a linear size of 0.5 meter and a cell size of about 50 micrometers, only about one cell in ten thousand is in direct contact with the outside world.

In a large internally correlated system, most resources are spent on maintaining internal stability rather than on interacting with the environment. These maintenance costs are often cited as one reason why very large systems become inefficient. But what may matter even more is that, once the system’s decision-making core becomes decoupled from the environment and enclosed in the comfort provided by internal homeostasis, it can generate decisions that have no environmental validity and drive the system as a whole toward degradation.

The human brain provides an example. It consumes a disproportionately large share of total body power and can be biochemically induced to generate feelings of satisfaction and passivity even under life-threatening external conditions.

The greater the energy imbalance between the decision-making core and the peripheral parts that interact with the environment, the greater the potential for dangerous distortions. Therefore, as the system grows larger, the reliability of information gathered about the natural environment acquires primary importance.

Changing the software?

One of the most interesting suggestions I have come across recently is that our current predicament might have been avoided had our information gathering been governed by different principles. This idea complements the proposition that human self-awareness of the predicament could itself become a central part of the solution—what Nate Hagens refers to as the “fifth law of thermodynamics”.

In “The Path to the Singularity: An Ideological History”, Steven J. Newbury (2026) describes three approaches to information gathering. Two, in his view, led to miserable outcomes, while the third was never historically pursued.

• The “Strong” (Mechanistic/Reductionist) Enlightenment — the mechanistic idea of nature as a clockwork that can be decomposed to elementary parts and, as a clock, practically lacks dissipation. The author believes that this neglect of entropy (dissipation) is what has driven our species to the current state of overshoot. Champions: Bacon, Descartes.

• The “Romantic” (Counter-Enlightenment): a reaction against the “soulless” Strong Enlightenment. Champions: Rousseau, Herder.

  It rejected the ”clockwork” and instead championed emotion, intuition, and the ”organic” or ”spiritual” essence of a people (the Volk). While it correctly identified the soulless, alienating nature of the reductionist worldview, its ”solution” was equally dangerous. By replacing universal reason with essentialist, ”natural” hierarchies based on ”blood and soil,” this tradition provided the ideological seedbed for the ethno-nationalism and Fascism that would emerge later. It was another form of reductionism, just biological and spiritual instead of mathematical. (S.J. Newbury)

• The Sceptical (Empirical/Emergent) Enlightenment:

  This tradition (David Hume, Adam Smith) represented a profoundly different path. It was not based on a priori rationalist design but on a posteriori empirical observation and scepticism. This was the true scientific method—a critical, observational, and materialist worldview. It saw systems (like economies or societies) as emergent, complex, and historically contingent—the very antithesis of reductionism. (S.J. Newbury)

I would mention two things in passing. First, I agree that the path, in which information is gathered and shared predominantly through emotions rather than intellectual assessment, is dangerous precisely because emotions are subjective and therefore divisive rather than unifying. As I noted in a previous post with regard to Rob Lewis’s essay “The Mystery at the Heart of Things. Are Facts Enough?”, the same emotional appeals can provoke drastically different responses in people with different backgrounds.

Second, I think that the main difference between the destructive and the constructive routes lies not only in mechanistic versus systems thinking, but also in the way scientific problems are posed. The dominant route of our information gathering has been governed by the question “What can be done?”—to facilitate growth and increase competitive capacity. A constructive route could instead focus on asking “What should not be done?”—so as not to undermine long-term persistence. This is what the concept of biotic regulation is about.

At present, for example, biological science focuses mainly on evolution—that is, on how genetic information changes—whereas in the second route it would focus on stasis, that is, on why genetic information does not degrade in the first place.

My main point, however, is that the probability that adequate information gathering will be spontaneously chosen by decision-makers cut off from environmental stimuli must be low—much like the probability that a color-blind person, presented with many pills, will spontaneously choose the one of the right color.

The overall implication of these considerations is that large size and large power consumption tend inevitably to produce detachment from reality and thus threaten persistence. Therefore, since life has persisted, these tendencies must be strictly limited in natural ecosystems. Let us take a look at how this is achieved.

Inequality in Nature and Human Society

Modern life comes in all sizes, from bacteria to whales. Different size means different per capita energy consumption, because per unit mass energy consumption is broadly size-independent (see “The Small and the Big: Life’s Fundamental Energetic Dichotomy” for graphs and sources).

Judged on a per capita basis, the inequality of energy consumption across life is astounding. At opposite ends of the spectrum, a whale with a body mass of 100 tons and a bacterium with a cell mass of one picogram (10^-12 g) have rates of energy consumption that differ by a factor 10²⁰ (a hundred-billion-billion-fold difference).

By comparison, income differences in global human society are far more compressed. The poorest people on Earth live on a few dollars per day; their annual income is only about a million times lower than that of the richest billionaires.

However, when we look at the global picture, things change in a radical way.

In global human society, the poorest 50% of individuals receive less than 10% of global income, while the richest 10% receive more than 50%.

Meanwhile, in stable natural ecosystems such as forests, the smallest organisms, though consuming the least per capita, can claim more than 90% of total ecosystem productivity. By contrast, the “energy multibillionaires” — the largest animals — despite their vastly greater per capita energy consumption, are allowed to consume no more than about 1% of total ecosystem productivity. In other words, they are exceptionally intense energy consumers, but nature keeps their numbers exceptionally low.

Distribution of energy consumption versus heterotroph body size in stable natural ecosystems (solid contour) and in current human society (excluding deforestation; dashed contour).

While everyone understands what an income-inequality diagram shows, I would like to provide some context for how the above distribution, showing the energetic dominance of the smallest consumers, is derived.

Walking in the forest, we notice that most of what the forest generates in energetic terms is leaf biomass. Every autumn we can see how many leaves are dropped from the trees to form a carpet on the ground. Evergreen trees such as spruces, for example, maintain such a carpet beneath them permanently. This carpet, however, does not accumulate from year to year in a mature forest: it disappears. Its disappearance is a sign that it is being decomposed by the invisible smallest heterotrophs—bacteria and fungi. So, as a first approximation, one can estimate the large consumption of these smallest actors from the seasonal disappearance of fallen leaves.

Spruce needles on spring snow

The simplest task is to calculate the energy consumption of the largest animals, mostly vertebrates. Their individual energy-consumption rates have been measured in laboratories for hundreds of species and predictably depend on body mass. Thus, by calculating their population densities—which is easier for large animals, since they are readily seen—and multiplying by per capita consumption, then relating the result to the primary productivity of the supporting ecosystem, we obtain their share. An example of how this is done for the boreal forest ecosystem can be found in this work.

We then need to estimate the contribution of the intermediate-sized animals, the invertebrates. This, too, can be done from their population densities. Sometimes researchers simply brush everything off a tree and then calculate the amount of living material associated with each tree. That their share is smaller than that of bacteria and fungi is clear from the fact that only a smaller proportion of leaves is normally eaten by insects. On the other hand, energy consumption by invertebrates turns out to be greater than that of the largest animals, because the total biomass of the former is larger.

The Small Effective Size of Trees

So far we have discussed energy consumers—the heterotrophs. It may seem that the energy producers, trees, are very large, and yet they claim about one half of the gross organic matter they synthesize for their own metabolic needs. The other half—the so-called net primary productivity—is consumed by the heterotrophs, as discussed above.

In reality, however, the effective energetic size of trees is very small. Green leaves have energy-consumption rates that are, per unit living mass or volume, comparable to those of animals.

Green leaves globally contain only about 15 gigatons of carbon in biomass.

Meanwhile, the woody parts of trees, which make up most of their visible biomass (several hundred gigatons of carbon globally), are largely metabolically inactive, apart from the thin cambium layer. They do not consume energy, but serve structural purposes. That is why trees can remain alive even when their trunks are severely damaged, like the willow below.

It still has green leaves and branches, but its stem is almost entirely gone. Yet what remains is strong enough to keep the tree standing.

Furthermore, unlike the tightly correlated bodies of animals, leaves on a tree are only loosely correlated with one another, mainly through their common stem, and can function with a high degree of independence.

Outlook

We therefore conclude that both the production and the consumption of energy in natural ecosystems such as forests are carried out largely by small, approximately independent actors: green leaves and unicellular heterotrophs.

Such an organization of energy production and consumption, in which numerous small actors dominate, ensures an efficient transfer of environmental information to living organisms, allowing them to respond effectively to environmental perturbations and keep the optimal environment stable.

Organisms whose decision-making is insulated from the external environment by a large buffer—the multicellular body—play a smaller role in ecosystem-level decision-making, that is, in directing the flow of ecosystem energy and regulating environmental conditions.

This stands in contrast to the way energy flows are organized in modern human society, where larger actors dominate.

If higher energy consumption leads to (temporarily) greater competitive capacity, then increased system size will tend to be favored, since it is associated with higher energy consumption. But increased size simultaneously causes decoupling from the external environment through a diminishing surface-to-volume ratio. This degrades strategic decision-making.

From this perspective, a spontaneous increase in size and energy consumption—even when it appears to be accompanied by greater specialization and complexity of internal parts—can be understood not as a gain in orderliness, but as a common route of decay of a formerly persistent population of smaller objects. That is why human society has anti-monopoly laws.

In life, local decision-making by numerous independent actors results in global environmental homeostasis, because all these actors base their functioning on meaningful genetic programs that have been tested for environmental validity over millions and billions of years. In contrast, in modern human society our governing cultural programs are still confused and unstable. If we were simply to begin acting locally without regard for one another, we would accelerate rather than prevent chaos, and in unpredictable ways. Therefore, our species requires a certain overarching communication, as well as the development of local strategies that would be globally non-disruptive.

Once environmental conditions change, a moment may arise when a constructive strategy aimed at persistence suddenly becomes competitive. By that time, a global network of local actors ready to implement such strategies should already be in place. Until then, I believe we need to support one another and foster mutual understanding and respect as broadly as possible across cultural landscapes.

Related reading:

Introduction: The Great Water Problem of life on land, and forests as its solution

Several hundred million years ago, when the young terrestrial life was about to colonize land, it faced two serious challenges unheard of in the ocean. One was the shortage of water, which, under gravity, tends to leave land for the ocean. Another was the flammability of life’s stuff in the oxygen atmosphere. Exposed to such vagaries, prone to desiccation and burning, it looked like terrestrial life stood few chances to ever become as mighty and prominent as her primordial oceanic kin.

Fortunately for all inhabiting land today, the laws of nature provided life with an opportunity of solving both problems at one fell swoop. Water quenches fire. If life could evolve a mechanism to keep land wet, this would simultaneously minimize the probability of ecosystems burning alive. But how then could life bring moisture inland?

Earth is a blue planet: two thirds of its surface is covered with water. The most energetic among the water molecules break out from the liquid to become gas. The atmosphere of Earth bears an appreciable amount of water vapor that travels freely above the planetary surface with winds. If only life could find ways to (1) direct the winds inland and (2) extract moisture from the incoming air, the Great Water Problem of the terrestrial life would be solved.

Here comes the trick: water vapor is a condensable gas. The lower the temperature, the less water vapor the atmosphere can hold. When the temperature drops, the colliding vapor molecules no longer have energy enough to overcome the intermolecular attraction forces, so they stick together forming droplets: the water vapor condenses. As there is less gas, the air pressure drops. As the air pressure drops, the higher pressure elsewhere starts pushing the air towards the low-pressure area where condensation occurs. In other words, moisture extraction can itself drive air motion!

As birds and flying insects evolved a perfect “knowledge” of aerodynamics that enabled them to fly, life, when it raised from the ocean, “learnt” the above physical laws and evolved a mechanism, the biotic pump of atmospheric moisture, that allowed land to be moistened and life on land thriving.

The key process of the biotic pump is plant transpiration: terrestrial plants emit about three hundred water molecules per each molecule of carbon dioxide fixed by photosynthesis (Cramer 2009). Such “wastefulness” has been conventionally considered as an “inevitable evil” caused by biochemical and environmental limitations. However, plants are known to differ substantially in their water use efficiencies depending on their metabolic pathways. For example, the so-called C₄ plants may have water use efficiencies several times higher than their C₃ relatives (Vogan and Sage 2011). While it is apparently possible to spend less water, plants, and especially trees -- among which, remarkably, there are practically no “water-efficient” C₄ plants (Sage 2001; Osborne and Sack 2012) -- have evolved high transpiration rates.

Transpiration unlashes water vapor keeping the atmosphere close to the dew point when condensation can commence. The cooling necessary for condensation is provided by the Earth’s gravitational field. As an air parcel ascends, its potential energy grows, while the internal energy (and, hence, temperature) is accordingly reduced. To switch on the condensation over a large area, the forest enhances transpiration to drive the atmospheric humidity beyond the dew point. Upon condensation, the air pressure drops in the lower atmosphere facilitating inflow of moist air from the adjacent ocean.

The mighty Amazon rainforest illustrates this majestic process (Wright et al. 2017). While a grassland ecosystem, incapable of efficiently controlling its water cycle, meets the end of the dry season in the state of maximum desiccation, the Amazon forest, in sharp contrast, begins to photosynthesize and transpire most actively (Saleska et al. 2016). New, vigorous leaves sprout under the full sunshine of the dry season clear skies using the water carefully stored from the wet season. As transpiration grows, so does the atmospheric moisture. Condensation intensifies accordingly, modifying the land-ocean air pressure contrasts. Finally, moist air rushes inland from the Atlantic Ocean bringing the much-needed moisture to the forest. The wet season promoted by forest transpiration sets in two months earlier than it arrives to unforested regions at the same latitude around the globe.

Another biotic pump example is the Eurasian forest belt that spreads across the continent over seven thousand kilometers and, during the vegetation season, draws moisture in from the three oceans: the Atlantic, the Arctic and the Pacific (Fig. 1).

Fig. 1. Land-ocean precipitation ratio (LOPR) in the Eurasian forest belt and in the unforested Australia (after Makarieva et al. 2013). In Australia, precipitation over land is smaller than over the ocean at the same latitude in both wet and dry season. In the boreal forest in summer, when it is biochemically active in summer, precipitation is higher than over the ocean and uniform over several thousand kilometers across the continent. In winter, the forest is dormant and the biotic pump does not work. Both the forest and unforested Australia during the wet season are about 5 degrees Kelvin warmer than the ocean.

Why forests?

Not just forests (in their generic sense, meaning big tall plants forming a canopy) but also grasslands are able to enrich the atmosphere with moisture via evapotranspiration. Could the biotic pump be driven by grasses? Not really. The main obstacle is how to control condensation preventing extremes. Evaporation that replenishes atmospheric moisture is a slow process driven by solar power. In contrast, condensation can occur at an arbitrarily high rate. Once there is ascending air motion, condensation rate is proportional to the vertical velocity: the more rapidly the air ascends and cools, the more water vapor condenses releasing energy that drives the air motion. This process can self-accelerate to produce wind speeds common to hurricanes and tornadoes. Such rapid outbursts would deplete atmospheric moisture and cause prolonged rain absence. Meanwhile the remaining soil moisture would partly leak as runoff, partly evaporate into the dry atmosphere producing desiccation in plant life.

Tall tree canopy puts a break on these uncontrolled processes. First, it ensures turbulent friction that decreases wind speeds. Second, a reverse vertical temperature gradient is caused during daytime under the canopy, with the ground being the coldest, and the tree tops the warmest. To take moisture away from the ground layer, a rising air parcel would have to work against a strong buoyancy force, as it would be colder than the surrounding air. This prevents loss of soil moisture by uncontrolled evaporation. Short grasses do not develop such a gradient.

Grasses and herbs have always been an essential part of the forest ecosystem. When a large tree dies and falls, a big space (“gap”) opens up for succession to start that will ultimately culminate in another big tree occupying the spot. Succession is process of ecosystem recovery from a disturbance (e.g., big tree death or fire). Early stages of succession are dominated by non-tree species including grasses. They rapidly cover the disturbed soil with a green carpet preventing leakage of nutrients. While unable to do biotic pumping efficiently, forest grasses did not actually need it – they were provided with moisture by the surrounding trees. As long as the gaps occupied a small relative area in the forest, the biotic pump of the forest as a whole was not impaired.

The problem of large herbivores

So, to keep land moistened, life invented forest. Forests have huge biomass. This is the main distinction between terrestrial and oceanic life. They have comparable primary productivities, of about 50 GtC/year. But, amazingly, if we look through the oceanic surface, there is apparently nobody there to be seen! Primary producers, the phytoplankton, are invisibly small microscopic creatures. Their total mass is only about one gigaton of carbon compared to several hundred gigatons of wood biomass! Even the biomass of green leaves, at about 10 GtC, is an order of magnitude larger (Bar-On et al. 2018).

So, big trees brought with themselves an unprecedented abundance of plant biomass. This surplus of energy resources opened an opportunity for large mammals to evolve in the forest. As hunters, humans are genetically tuned to be pleased when seeing a big animal from a safe place. But pause to think that an elephant, and any big mammal, locally consumes energy at a rate hundreds of times exceeding what the biosphere can locally photosynthesize (~100 W/m² versus 0.5 W/m²). This makes big mammals potential destroyers of the entire ecosystem, if their numbers go unchecked. In a stable natural forest, big animals should consume no more than 1% of total productivity (Makarieva et al. 2020a).

As big mammals evolved in the Eocene and began to destroy the canopy exacerbating natural disturbances and creating big openings, the early successional species of grasses and herbs found themselves in progressively more favorable conditions (Sage 2001). As such grass species have normally existed benefiting from the rainfall-generating capacity of the surrounding forest, they did not possess the skills necessary to run the biotic pump. As these grass species begin to spread, a pronounced aridification of the global climate followed. The climate became more harsh and unpredictable.

So, when discussing the retreat of humid forests and the spread of grasslands at the Eocene-Oligocene transition, as well as the more recent spread of the “water-efficient” C₄ plants that transpire relatively little, increased aridity is mentioned as a possible cause favoring such expansions (e.g., Sage 2001; Osborne and Sack 2012). However, if we take into account the biotic pump mechanism, we can conclude that aridity was a consequence rather than the cause of the grasslands extension. The ultimate cause was the inherent instability of an ecosystem with high biomass, the forest, in the presence of big herbivores (Makarieva and Gorshkov 2010). Grassland dominance could be triggered by big mammals exterminating closed canopies. The biotic pump processes globally dwindled causing a drier climate.

We note in passing that the great extinction that happened in the end of the Eocene in the ocean affecting microscopic species (Prothero 1994a) might also have to do with the evolutionary appearance of the first oceanic mammals (cetaceans and others). As a modern counterpart, humans depleted a major part of macroscopic life in the ocean (Perissi and Bardi 2021).

One can say that with the advent of big mammals, the entire terrestrial life, except for the remaining forests that were cluttered to regions with more favorable geophysical conditions, fell into the “browse trap” (Staver et al. 2014). An ecological trap (landscape trap, fire trap etc.) is a term coined a decade ago to describe how repeated disturbances of the early successional vegetation by new disturbances (burning, grazing or, in the industrial context, cutting) prevents the ecosystem from recovery and puts it on the degradation trajectory (Lindenmayer et al. 2022). This degradation can be slow or rapid, depending on the disturbance regime. And here we come to our species.

Implications: Let’s overcome the big animal’s instincts before it’s too late

As a big mammal originated in savannah, the human species is genetically predisposed to at best appreciate individual trees rather than (closed canopy) forests. Not surprisingly, quite a lot of humans perceive a mowed lawn as etalon of natural (savannah indeed) beauty. The overwhelming majority of humans have never been in a natural forest. Except for the scale, what our species has been doing to forests – exterminating them – is unoriginal. Human population growth continued the devastation of forests that began with the appearance of the first big mammalian herbivores forty million years ago in the Eocene. Had humans been an arboreal primate, we would have perceived forests, and behaved, differently.

Besides being crucial for continental moisture transport that currently sustains the world’s major agricultural regions, natural forests (and natural oceanic ecosystems) stabilize climate by keeping it moist. The contemporary climate change narrative emphasizes the dynamics of the mean temperature (warming/cooling). However, major climate-related sufferings of today are linked to extremes like droughts, floods, heat waves rather than to the long-term mean changes of precipitation, wind and temperature. “Paradise lost” – that is how Prothero (1994a,b) characterized the Eocene-Oligocene transition from the warm, humid and stable climate of the forest-dominated Earth to the more modern-like colder, drier and severely fluctuating climate with a greater proportion of Earth covered by grasslands. [Having got rid of another clade of giants, the dinosaurs, the forests had been keeping the Earth stable for over twenty million years before the big mammals arrived.] Today, the remaining large-scale forests, the frontiers of climate stability, are still buffering against climate extremes (O’Connor et al. 2021) possibly preventing a tipping point towards a completely inhospitable state of the planet (Gorshkov et al. 2000).

Lacking the genetic program to genuinely respect forests, we could nevertheless appreciate their importance, and prevent their destruction, based on rational scientific arguments. For a long time, forests have been valued in terms of the market cost of the wood they produced. In recent decades, attempts have been made to apply the economic term of “services” to forest ecosystems and to assess the economic value to such “natural services” that people are apparently receiving “for free”. The next step in deepening our understanding of how forests matter for the Earth’s well-being should be the recognition of the drastically different climate impacts of disturbed versus undisturbed natural ecosystems. Currently, no such distinction is clearly made; in the result, pristine forests continue to be rapidly destroyed.

The concept of biotic regulation unambiguously highlights the unique feature of natural (in particular, forest) ecosystems (Gorshkov et al. 2000). It is these ecosystems that have a climate-regulating function and are able to keep the environment in a favorable state, at least during the life of humankind as a biological species. The time of natural restoration of the forest after disturbances that do not go beyond the sustainability threshold to a stationary (climax) state with maximum climate-regulating competence, is at least several hundred years. Heavily disturbed forests (artificial plantations, equal-aged forest stands, early successional forest species) do not have such a climate-regulating function. Taking into account the fact that further destruction of natural ecosystems will lead to irreversible degradation of the global climate and make it impossible for our civilization to live on Earth, the cost of natural ecosystems is reduced to the cost of human life itself as a unique phenomenon. Such a cost goes beyond the applicability of traditional economic theory and tends to an infinite value.

Since human civilization cannot exist without the transformation (destruction) of the natural biota (we are big animals genetically encoded to destroy plant life), the resolution of the contradiction consists in limiting the total consumption, including our population number. In the meantime, the economic and ecological functions of forests must be spatially delineated (Moomaw et al. 2019, Makarieva et al. 2020b, Cary et al. 2021, Betts et al. 2021). The exploitation of the forest should be allowed only in strictly prescribed areas, where it is followed by replanting after felling in the form of plantations. Intact and naturally recovering forest ecosystems should be protected from industrial-scale felling and restored over large areas in order to fulfill their climate-regulating functions. Such territories must not be privately owned (having an infinite price, they cannot be bought) or rented. In the context of progressive changes in the global climate, the nations must assume obligations to revise the legal framework for the economic regulation of the forest fund, taking into account these restrictions. Since it is difficult to carry out such significant reforms quickly due to the natural inertia of thinking, it is necessary to introduce an urgent moratorium on industrial felling of intact forest areas. Any violation of such a moratorium should be elevated to the rank of crimes against humanity.

References

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Makarieva A.M., Nefiodov A.V., Li B.-L. (2020a) Life’s Energy and Information: Contrasting Evolution of Volume- versus Surface-Specific Rates of Energy Consumption. Entropy 22(9): 1025. https://doi.org/10.3390/e22091025

Makarieva A.M., Nefiodov A.V., Morozov V.E., Aleinikov A.A., Vasilov R.G. (2020b) Science in the vanguard of rethinking the role of forests in the third millennium: Comments on the draft concept of the federal law “Forest Code of the Russian Federation”. Forest Science Issues 3(3). https://doi.org/10.31509/2658-607x-2020-3-3-1-25

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In 2023, we attended the Eastern Old-Growth Forest Conference in Moultonborough, New Hampshire. I made a joint presentation with Prof. Susan Masino, co-author of the proforestation concept, on Forests and Global Well-Being. There was also a session on Climate Implications, which touched on two topics: carbon storage and impacts of climate change on the forests.

Biotic Pump and Biotic Regulation research explores a distinct and complementary perspective: how natural forests contribute to climate and environmental resilience by regulating the hydrological cycle. During our visit, we also learned about remarkable community efforts in forest preservation, such as Save Massachusets Forests and Restore: The North Woods.

So when Glen Ayers and Don Ogden — hosts of the Enviro Show and long-time supporters of forest preservation in Massachusetts and beyond — invited me to speak about the biotic pump, I was happy to accept.

Please listen to the podcast above or read the slightly edited transcript below. At the end of this post, I discuss what was the most difficult part of the interview. I also list several other interviews from the past five years discussing the biotic pump and biotic regulation more broadly.

Introduction

Glen: How about a Quote of the Week?

Don: All right. This one I think is fitting for our show.

Those who contemplate the beauty of the earth find reserves of strength that will endure as long as life lasts. There is symbolic as well as actual beauty in the migration of the birds, the ebb and flow of the tides, the folded bud ready for the spring. There is something infinitely healing in the repeated refrains of nature—the assurance that dawn comes after night, and spring after winter.

And that’s a Rachel Carson quote [from The Sense of Wonder].

Glen: Rachel Carson, really a great poetic writer, if you’ve never read any of her books, and she has several great books besides Silent Spring. Very beautiful, eloquent writing.

Don: I think this brings us to our interview, Glen.

Glen: Yes, our interview with Anastassia, who explains some of these concepts behind forest protection, having to do with the need to protect large areas of forest, because forests actually regulate the global climate.

And this concept of the biotic pump is a big part of that.

So let’s hear from Anastassia and I hope you find this interesting.

Today on the Enviro Show, we are joined by Anastassia Makarieva, who is joining us amazingly from Russia. And we found out about Anastassia from watching a video, a YouTube video about forests and this concept of the biotic pump.

And I don’t want to try to explain that, Anastassia, because this concept is kind of mind-blowing for us.

And we’re forest activists here in the United States.

But if you would introduce yourself a little bit, tell us about you and then tell us about this idea of how the forests act to essentially create the climate or create the environment. The self-sustaining environment.

Anastassia: Thank you, Glen.

First of all, thank you for the invitation. It is a pleasure to be here and to share my knowledge with your listeners who I know are as concerned or maybe even more deeply concerned than me about how to preserve natural forests, which is our common heritage, independent of where they are.

So about myself, I work in the theoretical physics division in a research institute in St. Petersburg, Russia. So I’m a physicist, but historically my work was devoted to investigating the mechanisms, both physical and ecological, by which natural ecosystems do indeed create and maintain a favorable environment — the processes by which life keeps our planet habitable.

The Water Problem

And as we live on land, for us, I mean for all living creatures who inhabit land, of primary importance is the water cycle.

The water cycle consists of several processes.

It is precipitation. So we get some liquid water or solid water from the skies.

It is river runoff. So part of this moisture drains away to the ocean.

And we also have an invisible process, but which is very, very important.

And this process is evaporation.

Everybody knows about evaporation.

If we have a saucer with water and leave it in our kitchen, then we come back and see that there is less water or no water at all.

It is evaporation.

But there is a more important, ecologically or, as we say, biotically mediated process, which is called transpiration.

And it is ensured by green creatures, green things, by plants.

And it consists in the following.

When green leaves open those tiny holes — those tiny openings called stomata — to catch CO₂ molecules, because they need CO₂ to produce food for the rest of the biosphere, at that moment the moist inner milieu of the leaf opens, and huge amounts of moisture are emitted into the atmosphere. In fact, for every CO₂ molecule fixed, hundreds of water molecules can leave the plant.

And so we have these three processes, precipitation, river runoff and evaporation and transpiration, the latter two sometimes are combined into one term, evapotranspiration [even if such a combination is not totally legitimate].

And what’s the problem that life has solved?

If we think on a large scale and imagine a moment in the history of our planet when there was still no life on land — and then it began to rise from the ocean and had these barren continents to conquer, so to speak — how did life manage to solve this water problem?

And what is the problem?

As land is elevated above the ocean, whatever water you store — for example, in soil — drains back to the ocean under gravity.

So it cannot be fully recycled.

It leaks.

And it leaks very quickly.

One of the key numbers modern people should bear in mind is how much water we actually have. People don’t know.

For example, if there were no import of moisture from the ocean, how long would it take for rivers to drain all available water from the land?

People can’t even guess.

But in fact, it’s just a few years.

We are not talking about very deep, ancient water — but about the water that is easily available.

So it is a very transient store.

The problem life was solving, then, was how to ensure the transport of moisture back from the ocean.

And that’s why, when we turn to the water cycle, our question was: how do natural ecosystems — and forests in particular — influence the water cycle in ways that make it sustainable?

The Water Solution

And it turns out that the answer is both very elegant and, honestly, mind-blowing, because water vapor in Earth’s atmosphere has a remarkable property.

It is a condensable gas.

So if we have enough moisture at the surface, and this moisture rises, it cools.

We know that if we go up into the mountains, the air gets colder and colder.

So when air rises, it cools, and water vapor condenses.

When it condenses and precipitates, there is now less mass in the atmospheric column.

As the mass decreases, air pressure drops.

And when pressure drops and an area of low pressure forms, it pulls in air from adjacent regions.

If we consider land and ocean, this low-pressure area will draw moist air from the ocean.

So if forests are able to keep the atmosphere over land moist, they sustain this process of condensation and precipitation.

This, in turn, draws in moist oceanic air, which rises, precipitates, and continues the cycle.

And this inflow compensates for the continuous loss of liquid water that occurs through rivers.

So how can we view this in everyday terms?

I sometimes compare it to an investment.

The forest has capital: soil moisture. It is a very important stock of a precious substance — water.

The forest transpires from this stock. It takes resources from this capital and sends them into the atmosphere.

Then, in the atmosphere, condensation and precipitation occur.

And there is an arrival of moist air from the ocean that compensates for this investment, rewards it, and also offsets the loss of capital through river runoff — which can be compared to inflation.

If the forest does nothing and simply tries to preserve its capital, it will disappear anyway. It will be eaten up by “inflation,” because soil moisture will drain back to the ocean.

But the forest is “wise” — and I put this in quotes, because there is nothing mystical about the process. It is physically transparent.

By transpiring moisture into the atmosphere, the forest changes atmospheric dynamics.

And this dynamic helps the forest sustain the water cycle and remain viable in water.

That’s how it works.

The Old-Growth Water Competence

Don: Anastassia, this is Don. I do have a question. Can you explain — and this is explained, of course, in the video that brought you to our attention — how old-growth forests move water better than, say, young forests?

Anastassia: Yes, this is a very, very important question.

You see, this moisture transport involves a complex set of processes, many of which include positive feedbacks.

For example, suppose the atmosphere is very dry, far from the dew point. If the forest transpires into this dry atmosphere, but condensation does not occur because it is too dry, then all the moisture the forest has “spent” will simply be blown away by the wind.

So this investment, so to speak, will be totally lost, because there will be no condensation, no precipitation, and no moisture inflow.

It is therefore important for the forest to transpire the right amount of moisture at the right time.

If we speak about old-growth, well-developed forest ecosystems that have evolved in a particular region and are well suited to its geophysical conditions, they do this properly.

Such forests transpire when the efficiency of the resulting moisture import will be greatest, and they avoid losing moisture.

But naturally, forests experience periods of disturbance — for example, fires or windthrow.

Even without human impact, we know that on such disturbed sites natural succession occurs. The ecosystem has the capacity to self-restore.

If there is a disturbance, non-random processes take place that gradually recover both the environment and the ecosystem.

However, during this process of self-recovery, the ecosystem is unable to regulate external conditions as efficiently as it can when undisturbed. Its resources are focused on recovery.

For example, early successional plants — herbs or grasses — transpire less than trees in an undisturbed forest.

So a recovering ecosystem, and the young forest that forms, exist at the expense of the moisture transport ensured by the old-growth forest that still surrounds the disturbed area.

But today, forests have been disturbed to a very large degree. Essentially everywhere we see disturbances.

There is no proper regulation of the water cycle.

That is why early successional, recovering forests — or tree plantations, which is another story — are unable to regulate the water cycle effectively.

Evolutionarily, disturbed areas were usually a minority. They did not need the full capacity to regulate the water cycle efficiently.

One specific mechanism present in old-growth forests and absent in younger stands is the so-called under-canopy temperature inversion.

When we have a closed canopy with tall, large trees, sunlight is absorbed in the canopy, and the canopy becomes warmer than the surface.

So we have relatively cool air near the ground and warmer air in the canopy.

Because cool air does not rise, there is no spontaneous loss of soil moisture.

Soil moisture remains under the control of transpiration. It is used for transpiration and not wasted.

For example, if there is wind, it could otherwise be blown away — but under these conditions, this does not happen.

Fires follow logging

When we disturb the old-growth canopy — for example, replacing it with shorter, more scattered trees — we increase wind speed.

More importantly, we remove this temperature inversion.

Now the land, no longer protected by green leaves from sunlight, becomes the warmest layer in the vertical profile.

Soil moisture then evaporates — not through transpiration, but through direct evaporation — into stronger winds.

This depletes the ecosystem of moisture.

That is why fires often follow logging.

This disruption of the local water cycle depletes local water stores in a young, fragile ecosystem that is trying to recover from disturbance.

When we log — even selectively, thinking we remove wood so that it does not burn — we disturb the water cycle so strongly that flammability actually increases.

Recent global studies show that ecosystem vulnerability to drought correlates with the degree of disturbance.

The more we disturb forest ecosystems through logging, the less capacity they have to withstand drought.

But this — temperature inversion and increased wind speed — is only one aspect of a very complex set of processes that constitute the biotic pump and, more generally, the regulation of the water cycle by forests.

Another important aspect is temperature regulation through cloud formation via biogenic cloud condensation nuclei.

This capacity is also compromised in disturbed ecosystems.

So there are many aspects to this.

Landscape Trap

Glen: I just want to say we’re talking with Anastassia Makareva, the co-originator of the concept of the biotic pump. And I want to give you a real-life example that I experienced when I lived in Colorado, in the high-elevation areas of the Rocky Mountains.

I’m talking about elevations above 10,000 feet.

The U.S. Forest Service had gone in there in the 1960s and logged extensive areas of old growth.

When I lived there in 1990, those areas still had not grown back into forests — more than 30 years later.

In fact, the Forest Service had replanted those areas at least three or four times.

The young trees they planted died. They replanted every couple of years — and they kept dying.

If you look on Google Earth now, you can still see that those forests have not recovered.

There’s no forest there. They’ve essentially turned into meadows, with very little tree growth at all — large patch cuts surrounded by high-altitude old-growth forests that, I believe, are self-perpetuating and create their own sustaining environment.

For me, that’s a real-life example of what you’ve been talking about.

When the forest was carelessly removed and drastically disturbed, its ability to regulate the water cycle was lost — and the forest has not returned, even after 65 years.

It’s likely that it would take hundreds, maybe even thousands, of years for that area to become a functioning forest again.

That’s a concrete example of how such drastic disturbance disrupts the entire ecology and all of these interacting processes.

Everything is broken.

And what you’re left with is a self-perpetuating, highly disturbed area — nothing like what was there before the damage was done.

Anastassia:I can testify that there are similar situations — for example, in the Bavarian forests, where there have been large-scale bark beetle disturbances.

Bark beetle outbreaks are related to disruptions of the water cycle, because when trees are weakened by drought, they are less able to protect themselves against beetles.

So first there was logging, then some disruption of the water cycle, then bark beetle outbreaks, which contributed to further forest decline.

Ultimately, in the most fragile areas — such as mountain tops — the forests are now essentially bald.

And recovery is, as you say, very, very slow, if it occurs at all.

These are examples of what Australian researchers have called a landscape trap — a concept developed in studies of ecosystem collapse.

It describes a stable but depauperate state into which an ecosystem falls when disturbance exceeds a certain threshold, below which it would still be capable of self-recovery.

They studied this using the example of mountain ash forests. These forests experience fires from time to time — they are not rainforests where fires are very infrequent.

But when logging occurs, the forests become drier.

Then the next fire destroys even more forest.

Then there may be further logging, and ultimately the forest reaches a state where it is no longer able to recover.

The more we disturb the forest, the drier it becomes.

The drier it becomes, the more susceptible it is to fire.

And ultimately, it is pushed onto a path of complete degradation.

Of course, there are regions where this is less likely because they are geophysically wetter.

But in regions where water is already limiting, forests may function well if undisturbed.

But when we add disturbance pressure, they crash — and their water cycle crashes with them.

This is important to understand because water-cycle regulation is a dynamic process.

The forest “spends” moisture in order to gain moisture.

If one link in this cycle breaks, the whole system breaks.

If the forest transpires but there is no condensation and no precipitation, the moisture is simply lost — and drought follows.

Evolutionary Paradox?

So these processes must occur in the way they have evolved to occur.

If we talk to plant physiologists, they sometimes discuss what they call an evolutionary paradox.

Why did plants evolve to be so “wasteful” with water? They could, in principle, transpire very little.

We know there are plants that transpire relatively small amounts — for example, cacti.

And yet plants, especially trees, transpire abundant amounts of water.

Why such apparent wastefulness? [Is transpiration an “inevitable evil”?]

But it is not wastefulness. It is, as I said, an investment in a more efficient water cycle.

If they did not transpire so much, they would not be able to moisten the atmosphere sufficiently to change its dynamics and to draw more moisture to the regions where they grow.

Recent Research

You were asking about our recent research.

Biotic pump research began by examining precipitation distributions over forests and over non-forested regions — so it was more forest-oriented.

But then we realized that the physical principles behind these moist air circulations are not sufficiently explored.

More recently, we have moved further into physics — for example, studying tropical cyclones and hurricanes.

In tropical cyclones, condensation and precipitation are very well measured.

There are many events, so we have good statistics.

If we are correct about the physical mechanisms underlying biotic pumping in forests, we should be able to quantify the same mechanism — moist air being drawn toward low-pressure zones associated with intense precipitation — in tropical cyclones.

Since tropical cyclones are purely physical phenomena — much simpler than forests or any living system — they are very useful to study in order to persuade scientists and the broader scientific community that these mechanisms are indeed very powerful.

For example, one of our most recent findings — which is very important — concerns cyclone intensification.

When a tropical cyclone intensifies, its wind speed increases and its central pressure drops.

In very strong cyclones, pressure can drop by as much as 100 millibars per day.

We compared precipitation rates in these cyclones with the rate of pressure drop.

Recall that I began by explaining that when precipitation removes moisture from the atmosphere, mass is removed from the atmospheric column, and pressure drops.

What we found is that pressure in these cyclones drops at the maximum rate permitted by precipitation.

It is as if precipitation removes mass and the pressure falls accordingly. Of course, the dynamics are more complex than that — but the rates practically coincide.

This is a new result.

There are thousands of researchers studying tropical cyclones — especially in the United States, where this is a major concern — but no one had examined it from this perspective.

This is very important. It shows that the precipitation mass sink — which also operates in forests — is fundamental to the dynamics of such systems and to the resulting moisture inflow.

So this is very exciting science.

Beyond the feeling that it may contribute to preserving ecosystems — which motivates my research — it is also beautiful and exciting in purely scientific terms.

Concluding Remarks

Glen: We’ve been talking with Anastassia Makarieva. And Anastassia, before we go, I’d like you to tell our listeners how they can find out more about your research.

Can they follow you anyway online? And do you put any of your information out for public consumption, such as on YouTube or Substack or any of those kinds of venues?

Anastassia: Yes, thank you, Glen. I run a Substack called Biotic Regulation and Biotic Pump: How Natural Ecosystems Keep the Earth Habitable.

The address is bioticregulation.substack.com. You’re very welcome to read the materials there — and I also try to answer questions.

Glen: Great. Well, we really appreciate you putting some time from your research to talk with us and give our listeners kind of the intro to this biotic pump concept.

And also really appreciate your concerns about preserving forests and the importance of these old, mature and intact forests that we also share that love here in the United States.

But really want to appreciate you coming on to the show. And we will sign up for your Substack.

Anastassia: Thank you very much. And I want to say that I greatly appreciate the work American scientists have done in this field.

You should especially be proud of the proforestation concept that originated in the United States. I believe this idea should be broadly supported — proforestation meaning allowing forests to develop according to their own ecological laws, so they can reach their maximally competent environmental state, where biotic regulation operates at maximum efficiency.

Unfortunately, we are not progressing very well with this forest preservation. We’re losing every now and then. Not so many victories.

Glen: As one of our heroes said, wilderness needs no defense, just more defenders. And that’s where we’re at. We’re defenders of wilderness and the forests. And I agree.

You know, sometimes it seems like we’re not winning, but we actually feel like we have been making some progress here in Massachusetts.

That’s not the whole United States. Obviously, things are not going well in other areas, but we have been making some progress in Massachusetts here.

Anastassia: I wish you every success. When we were in the U.S. in 2023, we met people involved in forest preservation, so we know you have a vibrant community.

Glen: We do. And we’ll never give up. That’s the key.

Anastassia: Good. Champion this cause, and we will follow!

Don: I just signed up for your Substack, too.

Anastassia: Thank you — I truly appreciate it.

Glen: Thank you so much.

Anastassia: Thank you. Bye-bye.

Glen: Bye.

Don: Well, there it is. That video is a must-see — and we’ve posted the link on the blog.

My Summary

The most difficult part of this interview was explaining why old-growth forests are superior in terms of climate regulation. Given that we know very little about undisturbed ecosystems, this argument necessarily involves an appeal to complexity. (Complexity is central — we even organized a conference on it.)

Environmental regulation is a highly complex process. It involves enormous fluxes of matter and energy, and high rates of information processing — “very,” “high,” and “huge” all in comparison with the capacities of our civilization.

When a process is complex and we do not fully understand how it works, we cannot expect it to continue operating at the same efficiency once we interfere with it (i.e., log the trees). That is the crux of the argument — to which one can add specific mechanisms (such as under-canopy temperature inversion, and many others).

But all this requires a certain basic capacity to comprehend complexity — something that may not be easily cultivated in simplified urban environments.

There is also a vicious circle: being unable to appreciate complexity, we ignore it in wild nature, destroy it, and are left with even less complexity.

It remains an open question whether the same scientific knowledge persuades people equally, given different baseline levels of comfort with complexity. However, likewise, the same emotional appeals can produce even more drastically different responses in people with different backgrounds.

Thus, while I agree with Rob Lewis’ concerns, expressed in his recent thoughtful piece “Are facts enough?”, that relying purely on scientific explanations of why wild nature matters may cause us to sacrifice something internally important, I still believe that rational arguments linking wilderness preservation to human well-being can have broader, more universal appeal.

At the same time, we should use every means available.

Recent Biotic Pump Interviews

2025 The Great Simplification — with Nate Hagens: Why We Need Forests: Their Vital Role in Climate Dynamics, Rain, and The Biotic Pump

2023 The Return of Old Growth Forests, a Ray Asselin film: Biotic Pump explanation

2022 Pascal Cuissot’s film “Rivers Above the Canopy”

2022 Climate Water Project — with Alpha Lo: Biotic Pump

2021 Planet: Critical — with Rachel Donald: Save the Forests to Save the Planet