Satellite observations have revealed methane leaks from landfills across Turkey, including one near Istanbul that ranks among the largest recorded landfill emitters in the world, before the country hosts the COP31 climate summit in Antalya from 9 to 20 November.

Turkey has made methane reduction a priority for the summit. Methane is the biggest cause of climate change after carbon dioxide, and is more than 80 times more potent in its first 20 years in the air.

Researchers at the University of California, Los Angeles analysed public Carbon Mapper data from the Tanager-1 satellite, covering January 2025 to the end of May 2026. They identified 70 plumes from Turkey's 10 highest-emitting waste sites, where average rates ranged from 841 kilograms to 7.4 metric tons of methane an hour.

One of the world's largest emitters

The landfill west of Istanbul near Seymen showed an average detected rate of about 7.4 tons an hour, just below the highest-emitting landfill on a global list from 2025. Gas from the site is collected and burned to generate electricity.

Turkey is the world's fifth-biggest emitter of methane from solid waste, behind China, the United States, Russia and Brazil, according to Climate TRACE. Its waste methane emissions rose nearly 25 percent in the decade to 2024, against a global rise of 6.5 percent.

Turkey's Environment Ministry said the satellite data were not from continuous measurements and could not be used to measure annual emissions. An ISTAC official said emissions there typically ranged between 4 and 6 tons per hour, and that one reading of 12 tons per hour had raised the average. Turkey is not among the participants in the Global Methane Pledge, which seeks a collective 30 percent cut in methane emissions from 2020 levels by 2030, but it could still join during COP31.