Istanbul landfill ranked among world worst methane emitters weeks before COP31 summit

Villagers on the rural outskirts of Istanbul have complained for years about a suffocating smell that drifts from the Silivri municipal waste dump, forcing them to keep windows shut even on hot summer nights. Satellite monitoring now confirms what their noses told them. The landfill is one of the worst single sources of methane ever identified anywhere in the world, and it sits in the country that will host the next United Nations climate summit.

Turkey is preparing to welcome governments to Antalya for COP31, the annual UN climate conference, from November 9 to 20, 2026. The host government has placed cuts to methane at the top of its agenda, arguing that curbing the gas is among the fastest ways to slow near-term warming. The awkward part is what satellites have been recording over Turkish landfills during the same period.

A Guardian investigation published on October 5, 2026, by Damian Carrington, Ruth Michaelson and Ayça Aldatmaz, reported that the Silivri landfill averages 7.4 tonnes of methane an hour. The researchers behind the finding, at the University of California, Los Angeles, say the planet-warming impact of that single leak is equivalent to roughly 1.5 million gas-guzzling SUVs. A second Istanbul landfill, in the Şile district, pours about 4 tonnes of methane into the atmosphere every hour, an impact compared by the newspaper to about 800,000 SUVs.

The findings land weeks before Turkey takes the COP31 presidency, and they raise an uncomfortable question for a government that has campaigned internationally on zero waste. Turkey is not among the 159 countries that have signed the Global Methane Pledge, which aims to cut methane emissions at least 30 percent from 2020 levels by 2030.

Key Facts

The Guardian reported on October 5, 2026 that Silivri is Turkey's largest landfill, processing 10,000 tonnes of waste every day. An on-site facility extracts 6,000 cubic metres of methane an hour to burn for energy, yet satellite observations show gas continuing to escape. The newspaper described the Silivri site as Turkey's worst super-emitting waste site and one of the worst identified anywhere by researchers at UCLA.

Turkish Minute reported on October 5, 2026 that the UCLA team used satellite data from Carbon Mapper, a nonprofit that tracks greenhouse gases, to identify the 10 Turkish waste sites with the highest average measured methane emissions. The observations were taken between January 2025 and June 2026. Silivri topped the list at 7.4 metric tons of methane an hour, followed by the Şile landfill at about 4 metric tons an hour.

The UCLA STOP Methane Project reported on April 22, 2026 that its most recent report ranked 25 waste facilities in 18 countries responsible for the largest super-polluting methane rates detected from space by key satellites in 2025, plus two additional Dishonorable Mentions. That April post noted that three of the largest methane plume sites are in Turkey: a landfill near Istanbul ranked 24th and another near İzmir ranked 25th on the top-25 list. A site in Silivri near Istanbul earned a Dishonorable Mention with an emissions rate of 8.4 tonnes an hour when the date range is extended from January 2025 up to April 7, 2026, a larger rate than any of the top 25 sites.

UCLA's STOP Methane Project reported on May 9, 2026 that its 2025 ranking drew on more than 2,994 plumes from 707 waste sites worldwide, including landfills and dumpsites. The top-25 sites emitted between 3.6 and about 7.5 tonnes of methane per hour, while the two Dishonorable Mention sites, Silivri in Turkey and Abidjan in Ivory Coast, reached 8.4 tonnes an hour and 4.6 tonnes an hour respectively. The report attributes the Silivri-Seymen site to the operator İSTAÇ, a subsidiary of the Istanbul Metropolitan Municipality.

Turkey's Ministry of Environment, Urbanization and Climate Change declined to comment on the findings, and the Istanbul Metropolitan Municipality declined to answer questions about Silivri's emissions and refused permission to photograph the site, according to the Guardian. İSTAÇ official Fatih Arslan attributed the leaks partly to exposed waste awaiting a clay covering, and said letting methane escape is a waste. Facility head Ebu Bekir Ikinci pointed to a 1993 landfill explosion that killed 39 people as evidence that conditions have improved since then.

Analysis

The timing could hardly be more pointed. Turkey has put methane cuts at the centre of its COP31 agenda. Environment minister and COP31 president-designate Murat Kurum wrote to the 196 nations due to attend that reducing methane is among the fastest and most effective strategies for slowing near-term temperature rise. First lady Emine Erdoğan has campaigned globally on zero waste and chairs the United Nations Advisory Board on Zero Waste. Against that backdrop, satellite data showing some of the world's largest landfill plumes inside the host country is a credibility test, not merely an environmental story.

What this really means is that the gap between diplomatic ambition and domestic enforcement is now measurable from orbit. Methane is a super pollutant roughly 86 times more potent than carbon dioxide over the short term, according to the UCLA STOP Methane Project, which means landfill leaks warm the planet quickly even though the gas leaves the atmosphere sooner than carbon dioxide. That short lifetime is precisely why methane cuts are described as the fastest lever available. It also means every year of delay at a site like Silivri locks in warming that a later cleanup cannot fully undo.

The technical explanation offered by the operator is instructive. İSTAÇ's Fatih Arslan blamed exposed waste awaiting clay cover. Dr Tia Scarpelli, waste sector lead at Carbon Mapper, said not all sites with gas collection are equal, and that leaks stem from poor maintenance, failed flares or systems that collect only good-quality gas. In other words, the presence of a gas capture plant, such as the facility at Silivri extracting 6,000 cubic metres of methane an hour, does not by itself prove that emissions are under control. Satellite instruments measure what actually reaches the sky.

Cara Horowitz, who leads the UCLA STOP Methane project at the Emmett Institute on Climate Change and the Environment, called the sites huge leaks and some of the largest single manmade sources of methane emissions in the world. She said diverting food waste from landfills and identifying the largest leaks would help Turkey cut emissions. That framing matters because it converts a national embarrassment into a fairly concrete to-do list. Diverting organic waste reduces how much methane is generated in the first place, while leak detection and repair address the gas that is already being produced.

Why It Matters

Methane emissions cause about a quarter of all global heating and have surged since 2007. Because the gas is short-lived compared with carbon dioxide, cutting it is one of the few climate actions with a measurable effect within a decade, which is why it has become a diplomatic priority. A host country that champions methane cuts while its own landfills rank among the world's worst emitters invites the charge of inconsistency, and that charge will be available to any delegation in Antalya that wants to raise it.

The local dimension is equally important. The UCLA post notes that landfill emissions carry health consequences for poor and marginalized communities that are more likely to live near these sites. Residents of villages including Yolçatı described years of odors forcing them to close windows on summer nights, and some feared repercussions if they complained. Kemalettin Özenç of Yolçatı told the Guardian simply that it suffocates you. In this sense, the satellite data gives a number to a burden that nearby communities have carried without much attention.

For investors and policymakers, the ranking also shows how cheap detection has become. The UCLA list used Carbon Mapper's public methane data from Planet Labs' Tanager-1 satellite and NASA's EMIT instrument on the International Space Station. Instruments cannot see in the dark or through heavy clouds, so more extreme events may exist that were not observed. That caveat cuts one way for operators and another way for regulators: the measured leaks are a floor, not a ceiling.

Next Up

COP31 opens in Antalya from November 9 to 20, 2026, with methane and waste management high on the presidency's stated agenda. The question is whether Turkey will convert that agenda into domestic action, including joining the Global Methane Pledge that 159 countries have signed, or whether the summit will produce commitments abroad that are not matched at home.

Watch for three things: whether Turkey's environment ministry responds to the satellite findings, whether İSTAÇ and the Istanbul municipality publish emissions data or allow independent access to Silivri and Şile, and whether the COP31 presidency invites the private sector, philanthropy, cities and civil society to bring initiatives to the summit, as Samed Ağırbaş, president of Turkey's Zero Waste Foundation, has urged.