Using satellite data to rank landfills with the largest methane plumes, we recently found the No. 1 site was a Buenos Aires landfill, with 110 large methane plumes observed over 21 days in 2025. That landfill had an emission rate of 7.6 tonnes of methane per hour — well over the global heating effect of one million SUVs.

Our report is generating lots of attention in Argentina. Last month, leading newspaper La Nacion ran a story looking into the emissions coming from this Buenos Aires landfill.

Now, it’s the subject of a report by CNN Latin America and CNN Global by journalist Iván Pérez Sarmenti who interviewed our Juan Pablo Escudero about UCLA’s findings and what landfills around the world are learning from this data. You can watch the story below or here en Español.

To do this work, UCLA’s STOP Methane Project reviewed public satellite data from independent nonprofit Carbon Mapper that showed 3,000 methane plumes from 700 waste sites worldwide. Sites like this Buenos Aires landfill are major opportunities for operators to fix mega plumes of methane that is driving global heating.

Read the full report here.

Speaking at London Climate Week, UN Secretary-General António Guterres just issued a major call for action on methane, the super-polluting greenhouse gas. The waste sector is one of the biggest opportunities for mitigating methane emissions and there’s some good news on that front.

Back in March, I wrote about our initial ranking of landfills based on partial 2025 data and how making reliable data on methane emissions visible to larger audiences is an effective way to trigger action. Now, I have more action to report.

In mid-April, we published a new updated ranking with all 2025 satellite data from Carbon Mapper’s public portal. Our list showed the 25 sites in the waste sector with the largest detected and quantified emissions rates worldwide, as seen by key satellite instruments in 2025. Since publishing, we continue to have promising outcomes from around the world.

Indonesia: From a Threads Post to an Official Response

A landfill located in Bantar Gebang, in Bekasi (West Java), Indonesia, appeared as #2 on our Top 25 list, with an average detected emissions rate of 6.3 tonnes per hour, roughly the equivalent of the emissions of one million SUVs.

Two days after publication, a Threads user with the handle abudiono mentioned the ranking in a creatively worded post: “Bekasi emang sensasional!” (”Bekasi is truly sensational! Even UCLA, a renowned US university, named Bekasi the second-highest area in the world! What’s that?”). The catch of course was that this #2 ranking was related to methane pollution, which the rest of the thread revealed with links to UCLA’s findings. The post got hundreds of likes and dozens of reshares.

Media and other accounts on Instagram picked it up and then Indonesian national outlets also covered the story, culminating in interviews with the Minister of the Environment and the Governor of Jakarta.

In the aftermath of this public attention, Indonesia’s Minister of Environment publicly committed to working with the Governor of Jakarta on the Bantar Gebang landfill crisis. Then, the City of South Jakarta went further, promising to stop sending waste to Bantar Gebang starting in 2027.

From appearing in our ranking to commitments from the local and national authorities to reduce methane emissions in two weeks, thanks to the help of some creative posts by social media users in that country. Not too shabby.

Mumbai: An Unannounced Court Visit

In India, a landfill in Mumbai appeared on our Top 25 list as #12. This landfill is known as the Kanjur Marg facility and reportedly receives roughly 90% of Mumbai’s daily waste, according to The Times of India. Many media outlets covered the story of our ranking, framing landfill methane as a major threat to the city of Mumbai.

It turns out, communities nearby had already been petitioning the Bombay High Court over the foul smell and health concerns near the site. In a hearing in late April, the court said that emission of methane gas needs to be tackled immediately, citing our Top 25 report. Then something happened that nobody expected. The court sent two judges to conduct a surprise inspection of the landfill and warned the Brihanmumbai Municipal Corporation (BMC) that if emissions are not curtailed, it could be forced to stop all activities there and find an alternative site.

The concessionaire and operator of this waste processing facility is Antony Lara Enviro Solutions Pvt Ltd. Representatives of the operator have been proactive in investigating the emissions detailed in our report.

Chile Round Two: This Time with Condors

Our most recent global ranking of super-emitting landfills includes three Chilean sites: Til Til, Talagante and Penco. Detected emissions from these sites averaged more than 5 tonnes of methane per hour. But the story that captured Chilean media attention this time wasn’t only about the methane emissions numbers. It was about condors.

It’s important to know that condors are a national symbol in Chile. So, images of the big birds circling the Til Til landfill, feeding from the trash and surrounded by (invisible) methane fumes, resonated with broader Chilean audiences. Chile’s main television network. Canal 13, even interviewed me during the primetime news show to explain what methane emissions are and why they matter.

Before recent efforts to bring attention to this problem from several organizations, including our rankings, methane emissions from landfills were not a big part of the mainstream conversation in Chile. Now, that’s starting to change. Methane is part of the nation’s environmental concerns. That’s an important step.

These cases are from three very different countries, with different priorities and social and economic realities. However, in each case, once emissions were made visible, action followed: a ministerial commitment in Indonesia, a court visit in Mumbai, a national primetime conversation in Chile.

Better management of landfills is a climate solution, which the UN Secretary General pointed to this week when he called for actions including decisive steps to reduce food waste, end open dumping, and capture emissions from landfills and wastewater. First, we need to know about those emissions. The data alone doesn’t reduce emissions. But it makes it harder for communities and authorities to look away.

The appetite for international cooperation on tackling methane pollution is growing and will take center stage at London Climate Action Week.

In late March, scientists and technologists from around the world gathered in Italy to mark the 250th anniversary of methane’s scientific discovery. In May, policymakers, business leaders and civil society met for an event held by the G7 presidency of France specifically to discuss how to confront methane emissions. And reducing methane emissions from the waste sector was one of three major targets announced last week at mid-year climate talks in Bonn, Germany, led by Türkiye and Australia, co-hosts of the next UN climate conference, COP31 in November. Amid this growing interest, methane emissions from the energy sector are near record highs, according to a recent IEA report.

Those are just a few of the reasons why methane—a greenhouse gas with a warming effect 80 times more potent than carbon dioxide over a 20-year period—has been in the headlines. Let’s take a closer look.

London Climate Action Week

The focus on methane will hit something of a crescendo next weekend when world leaders and NGOs converge at London Climate Action Week. Conversations in London are likely to center around energy security, climate action and competitiveness at a time of severe energy market disruptions from the war on Iran. But methane remains one of the biggest and fastest opportunities to slow climate change and is expected to be one area of potential agreement. London Climate Action Week, now in its eighth year, brings together more than 75,000 people across more than 750 events over nine days.

If you’re headed to London, here are a couple relevant event. Carbon Mapper is assembling a panel of experts to discuss how constantly improving remote-sensing technology, actionable data, policy, and local leadership can help drive methane emissions reductions across Europe and beyond. Their event is June 22 from 2:30-4:30 and open for registration here.

The following day, Tuesday June 23 at 11:15am, will feature “Abatement of Oil and Gas Methane Emissions,” an event hosted by RMI, the Salata Institute for Climate and Sustainability at Harvard, and SLB. Event organizers say they’ll discuss technology, policy, and economic opportunities to mitigate methane in this part of the energy sector.

Brazil Targets Methane Opportunities

Methane was also a topic of discussion at the inaugural Rio Nature & Climate Week, held in Rio de Janeiro, Brazil from June 2-6. Federal officials and experts there explored how methane presents an opportunity and a challenge to finding international cooperation, according to O Globo.

COP30 Executive Director Ana Toni, former Minister of Environment and Climate Change Marina Silva, and Congresswoman Sonia Guajajara participated in a panel that was part of the “Methane Forum: Emergency Climate Brake,” which gathered representatives from global organizations, public policy makers, scientists, communicators, and representatives from the productive sector and civil society across five sessions. Brazil ranks as the fifth-largest methane emitter globally, following China, the United States, India, and Russia, O Globo reported.

Methane from Waste Will Dominate COP31

Türkiye, co-host of COP3, has spent the last couple years talking about zero waste. Now, the COP31 presidency has set a goal to halve the growth in global waste by 2035, but key details about the goal are still missing, according to Climate Home News. Announcing the target, Turkish COP31 President-Designate Murat Kurum said waste was “one of the areas where the fastest results can be achieved” in climate action, but he did not specify the baseline for the target, or what types of waste it covered.

Türkiye featured prominently on UCLA’s STOP Methane Project’s recent Top 25 global list of landfill sites. The COP31 host had three landfill sites that made our list and our Dishonorable Mention.

Challenges to the EU Methane Regulation

We learned from news reports last month that the European Union appears to be bowing to lobbying pressure from the Trump administration and the fossil fuel industry to weaken its EU Methane Regulation, a flagship effort to fight the planet-warming super pollutant. Under a proposal, national governments would be able to grant exemptions to companies on “energy security” grounds, without a clear time limit or explicit oversight from the Commission, according to a draft document reported on by several media outlets. The EU’s methane regulation, which phases in gradually over the next few years, would ultimately impose penalties on fossil fuel companies that don’t monitor and limit emissions of methane. Last week, industry groups that oppose methane regulations indicated that easing penalties is not enough.

This attack on Europe’s regulations is playing out in the media. A recent piece of “sponsored content” published and promoted in POLITICO by ExxonMobil seems to misrepresent the impact of the methane rules on the EU’s energy system. “The claim that Europe could lose 43 percent of its gas supply is based on flawed premises,” Esther Bollendorff, Fossil Free Program Manager at Climate Action Network (CAN) Europe, writes in response.

Challenges to U.S. Deregulation

Here in the U.S., the Environmental Defense Fund is challenging a recent Environmental Protection Agency rule loosening methane emissions standard for the oil and gas industry in the D.C. Circuit. On June 4, EDF filed a lawsuit opposing the Trump EPA’s weakening of protections against methane. As a refresher, the EPA under Joe Biden in 2024 adopted standards to reduce methane pollution. This April, the Trump EPA moved to weaken those standards “to allow additional flaring of natural gas,” according to EDF. The petition for review was filed in the U.S. Court of Appeals for the D.C. Circuit. 

Methane Regulations Around the World

A team at Oxford University’s Climate Policy Monitor recently identified more than 100 methane policies across 32 jurisdictions (good) but fewer than one-third of these policies are mandatory (bad). And four major countries – India, Indonesia, Thailand and Tanzania – had no identifiable methane policies at all. “This is concerning as India and Indonesia together account for more than 12% of global methane emissions.” Helena Wright at Oxford writes at The Conversation.

My colleagues at the UCLA Emmett Institute published in 2023 one of the first global surveys of existing and proposed regulatory approaches to controlling anthropogenic methane emissions from the highest-emitting sources.

The Gates to Hell are Going Dark

The Darvaza crater, also known as the “Gates to Hell,” is the pit of constantly burning fire fed by methane gas in an isolated desert inside the Central Asian nation of Turkmenistan. Now the gates of hell are burning out, Jenny Gross reports for the New York Times.

Image of a methane plume in Silivri, Türkiye detected by the Tanager satellite on Nov. 25, 2025. Source: Carbon Mapper

Last month, a delegation of high-ranking Turkish officials came to New York to urge the nations of the world to reduce their greenhouse gas emissions from waste. The trip culminated in Turkey’s Minister of Environment, Urbanization and Climate Change Murat Kurum addressing the United Nations Headquarters with a global call to action on the U.N.’s International Day of Zero Waste.

“We believe that a cleaner, fairer, and more livable world is possible,” Kurum said, according to a press release following the visit. “Our Zero Waste movement is not just an environmental project, it is a movement of global conscience and a legacy for future generations.” 

As Turkey prepares to host the next United Nations climate conference, known as COP31, the country has been emphasizing zero waste as both a national and global goal under the leadership by Turkish first lady Emine Erdogan.

But our most recent report by UCLA’s STOP Methane Project shows that the COP31 host — and many other countries from all over the world — have work to do on reducing super-sized methane emissions from the waste sector. The report ranks 25 waste facilities in 18 countries responsible for the largest super-polluting methane rates detected from space by key satellites in 2025. The report identifies two additional “Dishonorable Mentions” for waste sites with emissions rates that fall within our top 25 range, if observations since the end of 2025 are also included. All told, three of the largest methane plume sites are in Turkey. A landfill located near Istanbul (here) was #24 and another near İzmir (here) was #25 on the top 25 list. However, a site in Silivri near Istanbul earned a Dishonorable Mention on account of the fact that it shows an emissions rate of 8.4 tonnes/hour if we extend the date range from January 2025 all the way up to April 7, 2026—a larger rate than any of our top 25 sites (data link here).

These super-polluting emissions detected by satellites present a real challenge, but also a major opportunity. When Brazil hosted COP30 last year, that country was able to put the spotlight on the problem of deforestation—not in spite of but rather because of its own struggle to protect the Amazon rainforest.

Turkey is wise to focus attention on cleaning up the waste sector where pollution, public health, and climate change intersect. Methane is a “super pollutant” 86 times more potent than carbon dioxide in the short-term so reducing methane emissions is the single fastest way to reverse rising global temperatures. Landfill emissions have health consequences for poor and marginalized communities that are more likely to live near these sites. Governments have a responsibility for ensuring that both municipal and private landfill operators are using best practices to reduce their own methane emissions. The host country can elevate an issue like this during the event and formal negotiations.

Samed Ağırbaş, President of Türkiye’s Zero Waste Foundation, recognized that improvements to the waste sector will take multiple players, during the recent New York visit. “We need the private sector, philanthropic leaders, cities, and civil society,” he said. “I warmly invite everyone to bring their initiatives and their partnerships to COP31.”

That’s a good first step—especially if these public and private sector leaders come ready to use the lessons we are learning from methane observation data, like the those that Carbon Mapper is publishing for the world to see.

• UCLA’s STOP Methane Project publishes user-friendly rankings of super-polluting methane emissions, including potentially responsible operators.

• Brazil and Chile each have three landfills on the top 25 list.

• The No. 1 site on the top 25 list is a landfill near Buenos Aires, Argentina with an emission rate of 7.6 tonnes of methane per hour — well over the global heating effect of one million SUVs.

• Three of the largest methane plume sites are in Turkey, home of the next United Nations (UN) climate conference (COP31). The country pledged to reduce waste emissions ahead of the conference.

• In addition to the top 25 sites, this release also includes two additional “Dishonorable Mentions” for landfills in Turkey and Ivory Coast.

UCLA’s STOP Methane Project released a new ranking of super-polluting methane emissions from the waste sector that includes three sites in Turkey, home to the next UN climate conference in November 2026. The report, “Spotlight on the Top 25 Methane Plumes in 2025: Landfills,” uses Carbon Mapper’s public data based on direct observations from 2025 to identify the waste sites with the largest quantified emissions rates worldwide — each site representing a major opportunity for operators to cut emissions.

The report ranks 25 waste facilities in 18 countries responsible for the largest super-polluting methane rates detected from space by key satellites in 2025. These facilities are found in developed and developing countries of all income levels and in all world regions, including: Brazil (with 3 sites), Chile (3), India (2), Saudi Arabia (2), Turkey (2), Algeria (1), Argentina (1), Greece (1), Hong Kong S.A.R. (1), Indonesia (1), Iran (1), Israel (1), Kuwait (1), Malaysia (1), Mexico (1), the Philippines (1), Thailand (1), and USA (1).

As organic waste breaks down it generates methane, a potent greenhouse gas. The waste sector contributes an estimated 20 percent of human-caused methane emissions globally. However, there are steps to collect and mitigate methane from the waste sector. Methane observation data can help find and fix leaks from landfills.

We are including a column titled “potentially responsible operator.” This information was not obtained directly from Carbon Mapper. Instead, the information is the result of research conducted by our team at the Emmett Institute.

For the first time, the list identifies two additional “Dishonorable Mentions” for waste sites with emissions rates that fall within our top 25 range, if observations since the end of 2025 are also included. These are sites near Istanbul, Turkey and Abidjan, Ivory Coast. This new data comes as Turkey prepares to host COP31, the next annual UN climate conference, and has launched an initiative to clean up its waste sector led by First Lady Emine Erdoğan. Notably, the landfill near Istanbul shows a larger emissions rate than any of our top 25 sites. (The data link for Silivri is here. The data link for Abidjan is here.)

“This list shows there is a lot of work to be done and not just by the COP31 host,” said Cara Horowitz, Executive Director of the UCLA Emmett Institute. “We are talking about seriously dangerous levels of methane coming from the waste sector in a wide variety of countries. Many of these sites sit close to cities, and their emissions pose real risks to public health. The good news is that governments and landfill operators can take practical steps to prevent these massive plumes.”

Identifying emissions of methane, one of the most potent heat-trapping gases, is easier thanks to satellite instruments that can detect methane from orbit. UCLA’s rankings are based on public satellite methane emissions data from the independent non-profit Carbon Mapper.

Researchers from UCLA’s STOP Methane Project analyzed data showing nearly 3,000 plumes from more than 700 waste sites worldwide to identify the Top 25 sites globally. These sites were responsible for the most acute hourly emission rates seen by the instruments worldwide – with emission rates ranging from 3.6 to 7.5 tonnes of methane per hour. To put that in perspective, a source emitting 5 tonnes of methane per hour (5,000 kg) would contribute about as much to global warming as one million SUVs.

Two landfill operators in Chile (Penco and Talagante) have already reported taking mitigation steps to address the methane emissions disclosed in the initial version of this 2025 list.

“We have already seen how making reliable data available to larger audiences and increasing visibility can be an effective way of prompting action,” said Juan Pablo Escudero, a project partner with UCLA’s STOP Methane and a Professor at Universidad Adolfo Ibáñez School of Law in Santiago, Chile. “This data provides great opportunities for responsible operators and national governments to lead the way on cleaning up their waste sectors.”

STOP Methane is a project of the UCLA Emmett Institute, a leading environmental law center in the U.S., which regularly releases user-friendly ranking lists of super-polluting methane emissions across multiple sectors, including oil and gas. 

Read the full report

Image of a methane plume in Encinal, Texas, detected by the Tanager satellite on Feb. 1, 2025. Source: Carbon Mapper

Texas is playing host to a who’s who of energy industry executives right now at CERAWeek by S&P Global conference in Houston. At events like this, industry leaders often talk about how much cleaner and safer production of oil and gas is here in the U.S. But new satellite data tells another story.

UCLA’s STOP Methane Project just released a new ranking that finds Texas tops the list of persistent super-emitter sites in the U.S. oil and gas sector. The report, titled “Spotlight on the Top 10 Largest Persistent Plumes in 2025: U.S. Oil & Gas” uses Carbon Mapper data from all of 2025 to identify seven sites in Texas, two in Louisiana, and one in Oklahoma.

These sites had emission rates ranging from 820 kilograms to 1,812 kilograms of methane per hour. For reference, the U.S. Environmental Protection Agency defines “methane super-emitters” from oil and gas as any event that emits at least 100 kilograms of methane per hour. The sites were also persistently stubborn sources of methane: At every site on this list, emissions were detected at least three times over the course of the year and were seen at least half the time that satellites observed the sites. 

A Texas site also features prominently on UCLA’s recently released global ranking of the 25 sites in the oil and gas sector with the largest detected and quantified emissions rates worldwide. The number 9 site on that list is a facility in Stanton, Texas, with a whopping emissions rate of 5.5 tonnes of methane per hour (metric tons). See coverage of that global list here by The Guardian.

This new U.S. data highlights the need to address methane emissions from the oil and gas sector as the U.S. ramps up LNG production and exports. Last week, U.S. Sen. Sheldon Whitehouse launched an investigation into a discrepancy between reported and observed methane pollution from the Permian Basin—the largest-producing oil field in the United States. 

“Texas and other states in the U.S. do not want to be known for stubborn super-polluting plumes of dangerous methane and other co-emitted gases that are harmful to public health,” said Cara Horowitz, Executive Director of the UCLA Emmett Institute. “Making the invisible visible is a powerful tool for taking action to decrease methane pollution — action that leads to healthier and more resilient communities here in the U.S.”

Reducing emissions of methane, one of the most potent heat-trapping gases, is a major priority for governments, philanthropies, NGOs, and civil society. At their disposal are powerful new tools: satellite instruments that can detect methane from orbit. UCLA’s rankings are largely based on satellite methane emissions data from the independent non-profit Carbon Mapper.

Reducing methane emissions can also save money. According to a methane calculator managed by GHGSat, a methane leak of 820 kilograms per hour (#10 on this list) equates to more than $1.1 million per year in lost product while an emission event of 1,812 kilograms per hour (#1 on this list) equals more than $2.5 million a year.

STOP Methane is a project of the UCLA Emmett Institute, a leading environmental law center in the U.S., which regularly releases user-friendly ranking lists of super-polluting methane emissions across multiple sectors, including landfills.

This year, the world celebrates 250 years since its discovery. No, I don’t mean America (though plans are underway to celebrate the semiquincentennial this July.) I’m talking about methane — that colorless, odorless, flammable and short-lived but super potent greenhouse gas that is helping heat the planet faster than carbon dioxide.

It was 250 years ago that an Italian physicist named Alessandro Volta first discovered methane while observing bubbles at Lago Maggiore in northern Italy — though he is perhaps better known for inventing the electric battery.

Alessandro Giuseppe Antonio Anastasio Volta was teaching experimental physics at a grammar school in the 1770s, focused on the chemistry of gases. By some accounts, he’d read a paper by Benjamin Franklin on the topic of “flammable air,” and was inspired to investigate the bubbles that he saw emitted from putrefying plant matter in swampy lakes in his area, when he discovered a new type of ‘inflammable air’ which he distinguished from hydrogen, the other “inflammable air.” He outlined his discovery in the publication Sull’aria Infiammabile Nativa Delle Paludi (“On the inflammable air native to swamp marshes”), according to an exhibit on the subject from St. Catharine’s College in Cambridge. Volta described how methane, when mixed with oxygen, could be ignited using an electric spark as delivered by the static electricity stored in a capacitor. (Relevant sidenote: Volta went on to create “the voltaic pile,” a stack of alternating zinc and silver discs separated by brine-soaked cloth. He found that when a wire was connected to both ends of the pile, a steady current flowed between the layers. This was the early form of the modern electric battery, which he unveiled in 1800. And yes, the electrical unit “Volt” is named after him.)

Next week, scientists, policymakers, and innovators will mark the 250 years since Volta’s discovery of methane by gathering for the Methane Action for People & Planet. The conference seeks to highlight the latest science on methane monitoring as well as the policy and technology innovations needed to rapidly cut methane emissions. Indeed, there are lots of innovations on both fronts.

Volta didn’t know it at the time but we know now that methane is a super pollutant 86 times more powerful than carbon dioxide in the short-term. It’s responsible for nearly 50% of recent global warming. And methane pollution has serious and dangerous health consequences. Reducing methane pollution is the single fastest way to reverse rising global temperatures, so CH4 has joined CO2 as a climate super villain. When it comes to which methane emissions to target, there is growing focus on “super-emitters” as the most meaningful way to pull the emergency break on global warming. Fortunately, we have powerful new tools for observing super-emitters: satellite instruments that can detect methane from orbit.

It is in this context that Carbon Mapper recently unveiled “Global Data to Drive Local Methane Emissions Action.” A year of data from the Tanager satellite has enabled Carbon Mapper to identify what it calls the most high-impact opportunities observed to date to reduce planet-warming methane emissions. “In Turkey, Argentina, Chile, and Malaysia, Carbon Mapper data collected between August 2024 and October 2025 show that just three waste sites account for roughly 19-36% of national solid waste emissions in each country,” Carbon Mapper says. That means that targeting just a handful of waste facilities would deliver major reductions to those countries’ total emissions.

In order to help identify the most extreme and most stubborn super-polluting plumes in various sectors, UCLA’s STOP Methane Project is releasing a new set of user-friendly ranking lists all this month. Last week, we unveiled the Spotlight on the Top 25 Methane Plumes in 2025: Oil & Gas, which garnered considerable media attention, including this story in The Guardian by Damian Carrington. Next, we’ll be releasing a list that focuses on largest persistent methane plumes from U.S. oil and gas sites, as well as a global ranking of largest detected plumes from the waste sector.

Our lists, largely based on Carbon Mapper data, put a spotlight on some of the biggest challenges and opportunities to reduce methane pollution. Some of our rankings also identify the potentially responsible operators involved. These are massive plumes of methane that, in most cases, did not spur news coverage at the time but that we can identify thanks to satellite instruments patrolling from space.

In 250 years, we’ve come a long way from Alessandro Volta staring at bubbles in the lake

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This week, for the first time, UCLA’s STOP Methane Project released a new ranking of super-polluting methane emissions that identifies the potentially responsible operator for each site. The report, titled “Spotlight on the Top 25 Plumes in 2025: Oil and Gas,” uses Carbon Mapper data from all of 2025 to identify the most extreme methane plumes in the world, and outlines opportunities for operators to cut emissions while saving money.

Spotlight on the Top 25 Plumes found that oil and gas facilities in Turkmenistan are responsible for most of the top super-polluting methane plumes detected from space by key satellites in 2025. This new data comes as Turkey continues to finalize a gas deal with Turkmenistan and as Turkmenistan’s president is reportedly planning an official visit to Brussels to discuss energy partnerships with the European Parliament. China is currently a major purchaser of gas from Turkmenistan. The report states that 15 of the Top 25 super-polluting sites are in Turkmenistan, whose state-owned gas company is one of the largest producers of liquified natural gas in the world.

“The goal of UCLA’s user-friendly ranking is to turn data into action and one way to do that is to provide governments and businesses with the best available information about where super-sized methane plumes are coming from so they can be addressed,” said Cara Horowitz, Executive Director of the UCLA Emmett Institute. “With gas exports a hot topic right now, our rankings could be seen as carrying a ‘buyer beware’ message for both current partners and potential buyers.”

Image of a methane plume in Esenguly, Turkmenistan, detected by the Tanager satellite on Dec. 21, 2025, with an estimated leakage rate of 18 tonnes/hour. Source: Carbon Mapper

Reducing emissions of methane, one of the most potent heat-trapping gases, is a major priority for governments, philanthropies, NGOs, and civil society. At their disposal are powerful new tools: satellite instruments that can detect methane from orbit. UCLA’s rankings are largely based on Carbon Mapper’s methane emissions data leveraging two space-based instruments: Planet Labs’ Tanager-1 satellite and NASA’s EMIT instrument on the International Space Station.

Researchers from UCLA’s STOP Methane Project analyzed 2025 data showing more than 4,400 plumes observed at nearly 2,500 oil and gas sector sites worldwide to identify the Top 25 sites. These sites were responsible for the most acute hourly emission rates seen by the instruments globally – with emission rates ranging from 3.7 to 10.5 tonnes of methane per hour. To put that in perspective, a source emitting 4 tonnes of methane per hour (4,000 kg) would contribute about as much to global warming in a year as one million SUVs.

“The list is a wake-up call to national governments that they will be held accountable for cleaning up methane emissions from the oil and gas production facilities they own or license,” said Mary Nichols, Distinguished Counsel for the UCLA Emmett Institute and former Chair of the California Air Resources Board. “While all operations emit some super-polluting methane to the atmosphere, it’s clear that owners can plug leaks, repair broken pipelines, and otherwise demonstrate their commitment to good housekeeping.”

STOP Methane is a project of the UCLA Emmett Institute, a leading environmental law center in the U.S., which regularly releases user-friendly ranking lists of super-polluting methane emissions across multiple sectors, including landfills.

This new list shows the 25 sites in the oil and gas sector with the largest detected and quantified emissions rates worldwide, as seen by key satellite instruments in 2025. (We published an initial list in November here.)

These insights come from Carbon Mapper’s methane emissions data leveraging two space-based instruments: Planet Labs’ Tanager-1 satellite and NASA’s EMIT instrument on the International Space Station. The non-profit Carbon Mapper processes the raw data from these instruments to detect, quantify, and pinpoint methane plumes, publishing the results on its data portal. Using published Carbon Mapper data, we determined the oil and gas sector sources with the highest detected hourly emissions rates seen from Jan. 1, 2025, to Dec. 31, 2025.

The 2025 data show 4,404 plumes observed at 2,489 oil and gas sector sites worldwide. These are sites in dozens of countries of all income levels and in all world regions. The sources on our “Top 25” list are responsible for the most acute hourly emission rates seen by these instruments globally – with emission rates ranging from 3.7 to 10.5 tonnes (metric tons) of methane per hour. Notably, the sources on this Top 25 list are concentrated in just a few countries, with the majority of the list consisting of oil and gas sites in Turkmenistan. Top 25 sites are also located in Venezuela, Iran, Pakistan, and the United States.

The sources presented here have been observed at least twice, and the emission rate reported for each site takes into account the number of times a plume was detected at that site. As the ability and coverage of space-based methane monitoring expands, further assessment of these sites and their emissions will become more reliable Still, the list presented here is a snapshot showing where the largest sources of oil & gas methane emissions are likely located globally, and highlights opportunities for near term mitigation.

In this iteration of our Top 25 list, we are including a new column: potentially responsible operator. This information was not obtained directly from Carbon Mapper. Instead, the information is the result of research conducted by our team at the Emmett Institute. Below, we explain the methodology for that research and welcome feedback.

Notes to understand and interpret this data:

How important are these sources of emissions in the global context? To illustrate how important these sources are, and what big opportunities they present for near-term reductions, consider that over a year, a source emitting 5 tonnes of methane per hour (in the middle of the pack of our “top 25” list) would contribute about as much to global warming as one million SUVs or one large (500 megawatt) coal-fired power plant.

How did we calculate these emissions rates?  We didn’t do the calculations. We are reporting calculations done by Carbon Mapper and included on their public data portal, making some judgment calls about what to include or exclude from our list as we explain below. Carbon Mapper gives source emission rates by averaging the emission rates from each time an instrument observed a source (including times, if any, when no emissions were observed). Carbon Mapper’s methodology for calculating emissions rate is described in more detail here. We obtained source-level methane emission data from Carbon Mapper’s data portal for the year 2025. Then we sorted and selected for the 25 largest emitters in the Oil & Gas category. For those observations, we used an automated process to pull associated emission information and location data from Carbon Mapper. We then used that location data to manually attribute each observation to a specific potentially responsible operator, which we explain at greater length below. For more questions about our methodology, please reach out to Horowitz@law.ucla.edu.

What do the two satellite instruments observe?  Tanager specifically images key regions of the globe where there are known oil & gas production activities, returning to those areas on a recurring basis (e.g., every few months). EMIT observes broad spatial areas in between 50°S - 50°N, including many oil & gas fields, as part of its broad earth science mission.

Why do our emissions rates look a little different than those reported on the Carbon Mapper site, e.g., the largest source is 10.5K kg per hour on Carbon Mapper and 10.5 tonnes per hour on our ranking?  We are reporting the same emission rates but are translating them into a different unit to make it simpler. One tonne (aka metric ton) equals 1,000 kilograms. Because the Carbon Mapper portal has to provide consistent formatting for hundreds of sources whose emissions rates vary from very small to very large, it uses the smaller unit (kg/hr). Since the Top 25 sources all have emissions rates in the tonnes range, we state them as tonnes, to make it simpler and to avoid having to say “10.0 K Kg.” Our emission rate for any given Top 25 site may also diverge over time from Carbon Mapper’s number for that same site, as Carbon Mapper updates its database to include additional observations of that site.

Does the list include every big emissions event the satellites saw?  No. Because of differences in the satellites’ orbits, some of these sources were seen many times in 2025, others just a few times. To be careful, we only included sources that were observed at least twice. So, there are a few oil and gas sector sources with extremely high emissions rates that appear on Carbon Mapper’s portal, but that we excluded from this list because they were observed only once.

Where can I learn more about methane observation from satellites?  To learn more about remote observation of methane and the opportunities and limitations presented by the new satellite data, see the Emmett Institute’s “Remote Sensing of Atmospheric Methane: A Primer for Policymakers on the Science of Methane Satellites.”

How did we determine potentially responsible operator information? In this iteration of our Top 25 list, we are including a “potentially responsible operator” column. This information was not obtained directly from Carbon Mapper. Instead, the information is the result of research conducted by our team at the UCLA Emmett Institute. We drew our conclusions from a holistic review of the best publicly available evidence. The amount of information available to us was heavily dependent on the emission source’s location.

Take, for example, the emissions in Stanton, Texas. Based on geodata and satellite imagery, we were able to confirm this source as either the Lenorah or Red Lake plant, which are both owned and operated by Energy Transfer. Detailed location and ownership data sourced from the Texas Commission on Environmental Quality helped us reach that determination.

In other instances, our determinations were based on a process of elimination. We assigned all sites in Turkmenistan to either Turkmengaz or Turkmennebit, the state-owned natural gas and state-owned oil companies, respectively. Due to a dearth of publicly available data, we have no direct confirmation that these sites are operated by Turkmenistan’s state-owned firms. However, we do know that the state largely restricts non-state-owned firms from operating onshore projects. Of the third-party firms that operate onshore oil and gas wells, only the Italian firm Eni appears to operate in an area near our detection sites. The Emmett Institute reached out to Eni, which confirmed that they had no active operations at the coordinates where plumes were detected. This leads us to conclude that state-owned firms are the potentially responsible operator for the sites included in this list. We welcome questions about our methodology, including questions about supporting evidence for operator information.

Something on the list doesn’t look right. Think we’ve got something wrong? Do you know something about one of these sources that suggests there’s an error in Carbon Mapper’s observation and calculation or our compilation and interpretation? If so, please explain it to us here.

Last November, we released a first-of-its-kind ranking of large methane emissions events from the waste sector with the intention to increase transparency and drive action to mitigate emissions. I have some encouraging news to share on that front.

Our first release, “Spotlight on the Top 25 Plumes in ‘25: Waste Sites” revealed the most extreme methane emissions rates worldwide from landfills seen by key satellite instruments in 2025 (up to the end of October), according to the data published by Carbon Mapper. That initial release has spurred action and accountability in Chile — home to two of the Top 25 sites.

Landfills in Penco and Talagante were No. 3 and 4 on that Top 25 list respectively, which drew substantial media coverage and national discussion, especially on TV news in Chile. Media outlets in Chile interviewed representatives from the companies related to both the Penco and Talagante landfills. Chile’s Environment Minister was asked to respond to the findings. In turn, the operators of both landfills responded to our list with information about their operations and, in the case of Talagante, with a public pledge to reform operations to reduce emissions going forward. Talagante’s landfill operator, Consorcio Santa Marta, appeared on TVN, the Chilean public TV network, to address its operations and its appearance on our list. It did not dispute our data but (correctly) pointed out that the data used for our rankings reflected only daytime observations and suggested that if the observations had taken place at night, the emissions rate would be lower. It noted a reason why daytime emissions are typically much higher than nighttime emissions: In the daytime, the landfill’s existing methane capture system often does not work optimally to generate electricity, because electricity transmission lines are too crowded to accept electricity during those hours. Importantly, the company went further and said that they are working to expand battery storage to enable daytime use of landfill gas and lower emissions.

Separately, representatives from the Penco landfill (which is operated by CEMARC now owned by the Canadian Consortium EBI) contacted our team about their site’s appearance in the Top 25 list. They noted that their ranking position was due to a single high-emission event on March 8, 2025, when emissions reached 15.6 t CH₄/h. They offered an explanation for this high emission rate, stating that it occurred during a temporary maintenance shutdown of the gas extraction system. This event, they said, did not reflect normal operations. The company expressed willingness to share operational records and collaborate with our team going forward.

The author, Juan Pablo Escudero (left), spoke this month before the Chilean Congress about regulating methane emissions in the context of a methane legislative guide prepared by the Andean Parliament. Escudero, a project consultant for UCLA’s STOP Methane, presented preliminary results of the UCLA ranking list to representatives, senators, and other authorities.

These cases illustrate several important points that are worth underlining.

First, these sorts of efforts — i.e., our list — can work to create public awareness and the kind of public pressure that can prompt action to reduce emissions. It garners the attention of media and policymakers for solutions. Companies pay attention and respond. Engagement of these types is a good development.

Second, it is worth noting that both of these Chilean landfills — and many of those on our initial list released in November — have gas collection systems. Although these systems allow for the reduction of methane emissions, they do not eliminate emissions entirely. Electricity generation is profitable only when the energy can be fed into the grid. If for some reason the gas is not collected — such as the lines being filled with cheaper energy, as happens during the day when solar energy is available — emissions can rise. Therefore, the mere existence of a gas collection system is insufficient if it is not complemented by other methods to reduce emissions.

Third, projects like UCLA’s STOP Methane — and the data we rely on — can help to pinpoint and showcase new opportunities for methane mitigation. While it’s true that satellite remote sensing technology detects methane emissions only at specific moments (rather than necessarily showing typical or average levels), even with this limitation satellite data can reveal important insights. Companies may have deficiencies in their maintenance routines or biogas collection facility operations, for example, and extremely high emission rate levels can reveal these deficiencies — and suggest high-leverage opportunities for correction.

In the case of the Penco landfill, it had that one significantly large emission event, however, the data also showed considerable emissions in all Carbon Mapper’s observations over that site. In the same sense, the Talagante landfill had over 20 significant events from Jan. 1 through Oct. 31 of 2025. In other words, it is true that satellite data is partial, but it is also true that the data shows consistently high emissions in every campaign over those landfills.

One alternative is to install batteries that allow electricity to be stored until it can be fed into the grid, thereby reducing the number of hours during which methane cannot be collected. However, this option remains very expensive and is only viable for some large-scale landfills.

In sum, this case proves that making reliable data available to larger audiences and increasing visibility is an effective way of prompting action. After the publication of this initial list, companies provided technical data, offered collaboration, and committed to reducing emissions. Although there are many things to improve, this is a step forward. UCLA’s STOP Methane Project is planning to release a full list of the Top 25 Plumes in 2025 now that all of the year’s data is available from Carbon Mapper, so watch this space.

Making methane visible works.

UCLA’s STOP Methane project got a big shoutout from U.S. Senator Sheldon Whitehouse during a recent COP30 event in Belém, Brazil on mitigating methane.

“The problem can’t be invisible,” Sen. Whitehouse said. “The satellites tracking all of this makes the invisible visible.” Whitehouse compared methane trackers to “fire fighters who need to go to a location to put out the fire.”

“Accountability matters,” he said, calling the launch of UCLA’s STOP Methane Project rankings “a really important step.”

We just released our Spotlight on the Top 25 in ’25: Oil and Gas Sector. The Top 25 sites are mostly in Turkmenistan — but also Venezuela, Iran, Pakistan, and the U.S. A site located in Cotulla, Texas is the sole U.S.-based operation in the Top 25.

“Embarrassing that the US is on this list,” Whitehouse said in a message on social media. “UCLA and Carbon Mapper are doing great work to expose wasteful methane pollution.”

Nearly 160 countries have joined the Global Methane Pledge to cut methane emissions 30% by 2030, and many private companies say they plan to measure, monitor, and reduce methane. A report out this week from the UN Environment Programme shows methane emissions from oil and gas operations, agriculture, and waste dumps are rising. Projected 2030 emissions are now lower than earlier forecasts due to new national laws, industry regulations, and market shifts. But current national climate goals would only provide an 8% reduction by 2030, so more action is needed.

Another analysis published at COP by the Climate Action Tracker coalition shows that adhering to methane pledges would avoid nearly 1 degree C from projected temperature rises this century.

Almost exactly 10 years ago, I got a call from a Los Angeles city leader asking if I’d be willing to attend a town hall in Porter Ranch, California, to help field questions about the unfolding disaster that was the Aliso Canyon natural gas leak, to provide background on environmental law for the discussion. As many of you know and may even remember, the Aliso Canyon natural gas storage facility leaked an enormous amount of gas into nearby neighborhoods for four months, unabated (and, at least initially, undetected and then unacknowledged by the storage facility’s operator). The negative health effects of the massive gas leak on local communities are still being studied, including by UCLA, where I’m executive director the Emmett Institute on Climate Change and the Environment. The leak is widely regarded as among our most serious recent environmental disasters. I showed up to the town hall to find thousands of residents rightfully angry, scared, and confused about how this could have happened in one of the most highly regulated states in the country. I’ll admit I was probably not very helpful, and I definitely could not provide the answers they deserved.

On Saturday, at an event at COP30 in Belém, Brazil, I heard CPUC President Alice Reynolds speculate that if California had had the tools then that it has today to detect large methane leaks, the state would have been far better able to respond promptly to the disaster. That’s almost certainly true. The extent of Aliso Canyon’s emissions came to light almost randomly as the event unfolded, in part because of one especially intrepid researcher who happened to be nearby, equipped, and ready to fly over the site with one of the very few planes then outfitted to detect methane aerially. But all of that took time — the leak had been active for a couple of weeks before that happened.

Methane remote sensing has come a long, long way. Today, multiple satellite instruments, including one launched with California’s support, can detect methane from orbit, at scales ranging from large individual point sources to continental-scale regions. Regulators in California get daily updates on leak detections, allowing them to work quickly and directly with operators when large leaks are seen. This has resulted in real victories and greenhouse gas emission reductions, as the California Air Resources Board described in an analysis it just released. (You can read more about these satellites and how they work here.) California has company. The global effort to reduce methane emissions has been a major focus of COP30 in Brazil. There’s an active and ever-expanding community of advocates, NGOs, philanthropies, and governments working to drive down super pollutants like methane.

But we’ve only scratched the surface of how to use these new data. Policymakers, operators of emitting facilities, and communities are still exploring how to use these tools to help achieve their goals — and they could use help. It turns out that methane emissions data alone are often not enough to drive action without significant amplification and public education. UCLA is launching a project that we hope will help. The Emmett Institute’s STOP Methane Project (“Spotlight on Top Plumes”) aims to make the new data more visible, understandable, and usable in guiding and motivating efforts to cut emissions.

We will do this by disseminating publicly available, science-based information about the most extreme emissions sources, in a form easily understandable by operators of emitting facilities, legal and regulatory authorities, and the public, to provide accountability and to motivate and assist in identifying and acting on the highest-priority emissions to cut, with breakdowns by emissions sector and region. Because of methane’s outsized role in driving global warming in the near term, every increment of methane reduction is a real opportunity, as many folks at COP30 are emphasizing (calling methane reductions the equivalent of a “climate emergency brake,” given how fast acting they are). Information like this can help direct efforts where they are needed most.

To kick us off, we just released our Spotlight on the Top 25 Plumes in ’25: Oil and Gas Sector, a list of oil and gas sites with the largest detected hourly emissions rates worldwide in 2025 (so far). It turns out that many of the oil and gas sites with the most extreme emission rates come from just a handful of countries — with Turkmenistan dominating the list, and Venezuela and Iran also cracking the top 5. Earlier this month, we published the Spotlight on the Top 25 Plumes in ’25: Waste Sites, a list of waste sites and landfills with the largest observed methane emissions rates globally for 2025. (Trivia time: Two U.S. cities have landfills on the global top 25 list. Can you guess which?)

We compiled these Top 25 in ’25 lists using public data from the nonprofit Carbon Mapper, a leading source of remote-sensed methane emissions data and analysis. (You can read more about Carbon Mapper here, and find its own recently released list of top persistent methane emitters across major oil and gas countries here — which complements our Top 25 list really nicely.)

We will regularly update these lists to provide an ongoing resource for journalists, industry leaders, policymakers, and the public. As the project expands, we will also draw on additional data sources to provide context to understand the impact and significance of specific large emitters, including on public health.

Stay tuned and make sure to subscribe to get updates from the project.

Cara Horowitz is the Executive Director of the UCLA Emmett Institute on Climate Change and the Environment.

This list shows the 25 sites in the oil and gas sector with the largest detected and quantified emissions rates worldwide, as seen by key satellite instruments so far in 2025.

These insights come from Carbon Mapper’s methane emissions data leveraging two space-based instruments: Planet Labs’ Tanager-1 satellite and NASA’s EMIT instrument on the International Space Station. The non-profit Carbon Mapper processes the raw data from these instruments to detect, quantify, and pinpoint methane plumes, publishing the results on its data portal. Using published Carbon Mapper data, we determined the oil and gas sector sources with the highest detected hourly emissions rates seen from Jan. 1, 2025, to today (using data posted on the portal by November 12).

The 2025 data show more than 3,100 methane plumes observed at more than 1,900 oil and gas sector sites, worldwide. These are sites in dozens of countries of all income levels and in all world regions. The sources on our “Top 25” list are responsible for the most acute hourly emission rates seen by these instruments globally – with emission rates ranging from 3.7 to 10 tons of methane per hour. Notably, the sources on this Top 25 list are concentrated in just a few countries, with the majority of the list consisting of oil and gas sites in Turkmenistan. Top 25 sites are also located in Venezuela, Iran, Pakistan, and the United States.

The sources presented here have been observed at least twice, and the emission rate reported for each site takes into account the number of times a plume was detected at that site. As the ability and coverage of space-based methane monitoring expands, further assessment of these sites and their emissions will become more robust. Still, the list presented here is a snapshot showing where the largest sources of oil & gas methane emissions are likely located globally, and highlights opportunities for near term mitigation.

Notes to understand and interpret this data:

• How important are these sources of emissions in global context? To illustrate how important these sources are, and what big opportunities they present for near-term reductions, consider that over a year, a source emitting 5 tons of methane per hour (in the middle of the pack of our “top 25” list) would contribute about as much to global warming as one million SUVs or one large (500 megawatt) coal-fired power plant.

• How did we calculate these emissions rates? We didn’t do the calculations. We are reporting calculations done by Carbon Mapper and included on their public data portal, making some judgment calls about what to include or exclude from our list as we explain below. Carbon Mapper gives source emission rates by averaging the emission rates from each time an instrument observed a source (including times, if any, when no emissions were observed). Carbon Mapper’s methodology for calculating emissions rate is described in more detail here.

• What do the two satellite instruments observe? Tanager specifically images key regions of the globe where there are known oil & gas production activities, returning to those areas on a reoccurring basis (e.g., every few months). EMIT observes broad spatial areas in between 50°S - 50°N, including many oil & gas fields, as part of its broad earth science mission.

• Why do our emissions rates look a little different than those reported on the Carbon Mapper site, e.g., the largest source is 10.0K on Carbon Mapper and 10 tons per hour on our ranking? We are reporting the same emission rates but are translating them into a different unit to make it simpler. One metric ton equals 1,000 kilograms. Because the Carbon Mapper portal has to provide consistent formatting for hundreds of sources whose emissions rates vary from very small to very large, it uses the smaller unit (kg/hr). Since the top 25 sources all have emissions rates in the tons range, we stated them as tons, to make it simpler and to avoid having to say “10.0 K Kg.” Our emission rate for any given Top 25 site may also diverge over time from Carbon Mapper’s number for that same site, as Carbon Mapper updates its database to include or to analyze additional observations of that site. Our emission rates reflect Carbon Mapper’s published data as of November 12, 2025.

• Does the list include every big emissions event the satellites saw? No. Because of differences in the satellites’ orbits, some of these sources were seen many times in 2025, others just a few times. To be careful, we only included sources that were observed at least twice. So there are a few oil and gas sector sources with extremely high emissions rates that appear on Carbon Mapper’s portal, but that we excluded from this list because they were observed only once.

• Where can I learn more about methane observation from satellites? To learn more about remote observation of methane and the opportunities and limitations presented by the new satellite data, see the Emmett Institute’s “Remote Sensing of Atmospheric Methane: A Primer for Policymakers on the Science of Methane Satellites.”

• Something on the list doesn’t look right. Think we’ve got something wrong? Do you know something about one of these sources that suggests there’s an error in Carbon Mapper’s observation and calculation or our compilation and interpretation? If so, please explain it to us here.

The data show more than 1,800 emissions observations from 600 waste sites, including landfills and dumpsites, worldwide. These are sites in dozens of countries of all income levels and in all world regions. While many landfills emit only a few dozen kilograms of methane per hour, the sites on our “Top 25” list emit much more – ranging from about 3 to more than 7 tons of methane per hour. Emissions rates vary over repeated observations, but the waste sites at the top of the list are persistently very high.

Spotlight on the Top 25 Plumes in ‘25: Waste Sites

Notes to understand and interpret this data:

How important are these sources of emissions in global context? To illustrate how important these sources are, and what big opportunities they present for near-term reductions, consider that over a year, a landfill emitting 4 tons of methane per hour (in the middle of the pack of our “top 25” list) would contribute about as much to global warming as one million SUVs or one large (500 megawatt) coal-fired power plant.

How did we calculate these emissions rates? We didn’t do the calculations. We are reporting calculations done by Carbon Mapper and included on their public data portal, making some judgment calls about what to include or exclude from our list as we explain below. Carbon Mapper’s reported emissions rate for a landfill is the average of the emissions rates determined each time an instrument flew over that landfill.

Why do our emissions rates look a little different than those reported on the Carbon Mapper site, e.g., the largest source is 7.4K on Carbon Mapper and 7.4 tons per hour on our ranker? We are reporting the same emission rates but are translating them into a different unit to make it simpler. One metric ton equals 1,000 kilograms. Because the Carbon Mapper portal has to provide consistent formatting for hundreds of sources whose emissions rates vary from very small to very large, it uses the smaller unit (kg/hr). Since the top 25 sources all have emissions in the tons range, we stated them as tons, to make it simpler and to avoid having to say “7.4 K Kg.”

Is your list equivalent to a list of the biggest landfill methane sources in 2025? Not entirely, for a few reasons, but it’s pretty close. These are the waste sites with the largest hourly emission rates that two instruments saw thus far in 2025, but 2025 isn’t over yet and the instruments can’t see everywhere. In particular, they can’t see in the dark or see through heavy clouds. So, while the observations of these sources are solid, it’s possible that there were even more extreme emissions events in 2025 that the instruments couldn’t see (or that we excluded from this list because of too-few observations, as noted below). Moreover, waste site emission rates do vary somewhat over time, so capturing high hourly emission rates on a set of particular dates is not the same as knowing how much a site emitted, in total, across an entire year. Nevertheless, in our judgment this is about as close as one can get, given current data, to a list of the largest waste site emitters in 2025 so far.

Does the list include every big emissions event the satellites saw? No. Because of differences in the satellites’ orbits, some of these landfills were seen dozens of times in 2025, others just a few times. To be careful, we only included waste sites that were observed at least twice. So, there are a few waste sites with extremely high emissions rates that appear on Carbon Mapper’s portal, but that we excluded from this list because they were only observed once.

Where can I learn more about methane observation from satellites? To learn more about remote observation of methane and the opportunities and limitations presented by the new satellite data, see the Emmett Institute’s “Remote Sensing of Atmospheric Methane: A Primer for Policymakers on the Science of Methane Satellites.”

Something on the list doesn’t look right. Think we’ve got something wrong? Do you know something about one of these landfills that suggests there’s an error in Carbon Mapper’s observation and calculation or our compilation and interpretation? If so, please explain it to us here or in the comments.

Thanks for being here. As you may know, methane accounts for about one-third of global warming. And because methane only stays in the atmosphere for a short time, cutting that potent greenhouse gas provides a critical opportunity to reduce near-term climate change. Recognizing this urgency, nearly 160 countries have joined the Global Methane Pledge, committing to cut methane emissions 30% by 2030, while many private companies have committed to enhanced measurement and monitoring of methane with a view to cutting emissions, under UNEP’s Oil and Gas Methane Partnership.

The Emmett Institute’s STOP Methane Project (“Spotlight on Top Plumes”) aims to make the new data more visible, understandable, and usable in guiding and motivating efforts to cut emissions.

We will do this by disseminating publicly available, science-based information about the most extreme emissions sources, in a form easily understandable by operators of emitting facilities, legal and regulatory authorities, and the public, to provide accountability and to motivate and assist in identifying and acting on the highest-priority emissions to cut, with breakdowns by emissions sector and region as appropriate.

Subscribe to this Substack below to get early access to all our upcoming rankings. Please share this site with others.

Please explore our first two lists.

We just released our Spotlight on the Top 25 Plumes in ’25: Oil and Gas Sector, a list of the largest detected and quantified emissions rates worldwide from oil and gas operations.

Earlier this month, we published the Spotlight on the Top 25 Plumes in ’25: Landfills, an initial list of waste sites and landfills with the largest observed methane emissions rates globally for 2025. Solid waste landfills are responsible for about 20 percent of global methane emissions and present a critically important mitigation opportunity, because landfill emissions can often be cost-effectively controlled, monitored, and reduced. UCLA’s STOP Methane Project compiled the Top 25 in ’25 lists using public data from Carbon Mapper, a leading source of remote-sensed methane emissions data and analysis. (Of course, all errors are our own.)

We will regularly update these lists to provide an ongoing resource for the benefit of journalists, industry leaders, policymakers, and the public. We will also draw on additional data sources to provide context to understand the impact and significance of specific large emitters.

How is UCLA’s STOP Methane Project different from other existing methane data collection efforts? High-quality, freely available methane emissions data alone are critically important but are often not enough to drive action without significant amplification and public education. There is an urgent need for a credible source to spotlight the most important emissions data, explain what it means, and make it easier for non-scientific actors to understand. That’s where STOP Methane comes in. Our regular updates offer contextualization from UCLA experts to show the impact and importance of specific emissions events while our tailored rankings provide strategic amplification to drive change.

There are powerful new tools to help support these commitments and provide accountability: satellite instruments that can detect methane from orbit, at scales ranging from large individual point sources to continental-scale regions. Policymakers, operators of emitting facilities, and communities are still exploring how to most effectively use these new tools to help achieve their goals—and could use help.

Our team:

Cara Horowitz is Andrew Sabin Family Foundation Executive Director of the Emmett Institute.

Edward Parson is Dan and Rae Emmett Professor of Environmental Law at UCLA School of Law and Faculty Director, Emmett Institute on Climate Change and the Environment.

Mary Nichols is Distinguished Counsel to the Emmett Institute, former Chair of the California Air Resources Board.  

Juan Pablo Escudero is a project lead for the Emmett Institute and Professor at Universidad Adolfo Ibáñez.

Evan George is Communications Director of the Emmett Institute. 

About the Emmett Institute at UCLA Law:

The Emmett Institute is the environmental law hub at UCLA and one of the top environmental law programs in the United States. Through groundbreaking research, public interest initiatives, and impactful legal clinics, the faculty and staff of the Emmett Institute help shape climate change and environmental law and policy in California, the United States, and jurisdictions around the world.

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