In the countryside west of Istanbul, trucks line up to empty mixed household waste from the city of 16 million people onto a vast landscape of decomposing rubbish, where landfill gas is captured to generate electricity at a nearby plant.
But far above the seagulls circling the waste, satellites detect what the plant has failed to capture: methane escaping at a rate that ranks it among the world’s largest recorded landfill emitters.
Türkiye hosts COP31 in Antalya from November 9 to 20 and has made methane reduction a priority for the climate summit.
Methane is the biggest cause of climate change after carbon dioxide (CO2) and is over 80 times more potent than CO2 in its first 20 years in the air.
Sharp cuts could therefore slow warming relatively quickly.
Turkey’s waste sector illustrates both the potential and the difficulty of achieving rapid cuts.
The country is the world’s fifth-biggest emitter of methane from solid waste behind China, the United States, Russia and Brazil, according to data from non-profit emissions tracker Climate TRACE.
Satellite observations analysed by researchers at the University of California, Los Angeles (UCLA) identified 70 plumes from Türkiye’s 10 highest-emitting waste sites, where average detected rates ranged from 841 kg to 7.4 metric tonnes an hour.
Three were around Istanbul, while others were near Ankara, Izmir and Antalya, where COP31 is being held.
Gas capture is widespread at Turkey’s larger municipal landfills, indicating that collection systems alone do not prevent large releases.
Tia Scarpelli, waste sector lead for emissions-monitoring non-profit Carbon Mapper, said cutting landfill methane requires diverting organic material before it reaches dumps, while improving rates of capture.
Because Türkiye largest detected emissions were concentrated at a few sites, addressing those landfills could deliver disproportionate gains, Scarpelli said.
“There is this huge mitigation potential by just addressing the largest landfills to reduce their national emissions,” she said, suggesting better-designed collection systems and repairs to cracked covers or faulty gas wells.
The UCLA analysis used public Carbon Mapper data from the Tanager-1 satellite between January 2025 and end-May 2026.
It showed an average detected rate of about 7.4 tonnes an hour from the landfill west of Istanbul near Seymen — just below the highest-emitting landfill on a global list from 2025.
“What stands out is how big its emissions are and how persistently large they are,” said Scarpelli.
In response to a request for comment, Turkey’s Environment Ministry said the data were not from continuous measurements and could not be used to measure annual emissions at the Seymen landfills.
