Satellite survey sheds new light on global solid waste methane emissions

Matthieu Dogniaux, Joannes D. Maasakkers, Marianne Girard, Dylan Jervis , Jason McKeever, Berend J. Schuit, Shubham Sharma, Ana Lopez-Noreña, Daniel J. Varon , Ilse Aben 

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.