Satellite survey sheds new light on global solid waste methane emissions

Anthropogenic methane emissions are the second most important contributor to climate change, and their rapid reductions could help decrease near-term warming. Solid waste emits methane through the decay of organic material, which amounts to about 10% of total anthropogenic methane emissions. Satellite instruments enable monitoring of strong methane hotspots, including many strongly emitting urban areas that include landfills as most prominent sources. We present a survey of methane emissions from 151 individual waste disposal sites across six continents using high-resolution satellite observations. We find that managed landfills and dumping sites show similar levels of emission and our satellite-based estimates generally show no correlation with reported or modeled emission estimates. This reveals major uncertainties in the current understanding of methane emissions from waste-disposal sites, warranting further investigations to reconcile bottom-up and top-down approaches. We also emphasize how high-resolution satellite observations can help pinpoint where emissions originate within a facility, which often aligns with the area where waste is added. Our results highlight the potential of high-resolution satellite observations to detect and monitor methane emissions from the waste sector globally, providing actionable insights to help improve emission estimates and focus mitigation efforts.