UN Expands Methane Alert System to Coal Mines and Waste Sites

The UN Environment Programme's Methane Alert and Response System will be expanded to cover coal mines and waste facilities, following satellite analysis that identified an Indian landfill in Kanjurmarg, Mumbai among the world's three largest methane-emitting sites. The expansion was announced on May 4, 2026 on the sidelines of a high-level methane event hosted by France under its G7 presidency.

UNEP's International Methane Emissions Observatory analysis published on April 23, 2026 found that of the three highest methane emitters globally, two were landfills — in Chile and India. Among the top 50 emitters, 22 were coal mines and 11 were waste facilities or landfills. A separate satellite analysis by Carbon Mapper and UCLA's Stop Methane Project identified two of the world's 25 largest methane-emitting landfill sites in India, at Secunderabad and Mumbai. The MARS system, launched in January 2023, has detected and helped mitigate 41 distinct methane super-emitter sources in 11 countries, with combined emissions estimated at 1.2 million tonnes of methane.

Methane is more than 80 times more powerful than carbon dioxide as a greenhouse gas over a 20-year period, though it breaks down after about a decade compared with carbon dioxide's residence time of hundreds of years, making rapid mitigation one of the most immediate ways to reduce near-term warming. The IEA has said plugging methane leaks could return about 200 billion cubic metres of gas to global markets annually. Alongside the MARS expansion, IMEO and the IEA released a MARS Response Blueprint setting out steps for countries to verify emissions, mobilise operators and track mitigation outcomes.

IMEO also launched a new Coal Methane Database containing mine-level methane emissions data for nearly 250 coal mines covering more than half of global metallurgical coal production, combining satellite observations, scientific research and official inventories. UNEP director for climate change Martin Krause said expanding MARS to coal and waste sends a clear signal that the era of invisible methane emissions is ending. MARS programme manager Meghan Demeter cautioned that satellites capture only the largest sources, and that system-wide progress on methane requires comprehensive measurement and reporting across all emission scales, not just super-emitters.

Key figure — 1.2 million tonnes of methane mitigated since MARS launch