Methane emissions from landfills in Brazil: a satellite-based assessment

Methane ( CH₄ CH 4 ) is a powerful short-lived climate pollutant, and landfills are a major anthropogenic source. Yet emissions inventories often rely on first-order decay (FOD) models and operator-reported recovery data that may miss real-world fugitive fluxes. This study compares methane generation, capture, and reporting in Brazilian and USA landfills by integrating high-resolution satellite plume quantification with official inventories from the clean development mechanism (CDM) program from the United Nations Framework Convention on Climate Change (UNFCCC) records. Thirteen Brazilian sanitary landfills, receiving about 18 Mt/a of municipal solid waste (MSW), were analyzed using Greenhouse Gas Satellite (GHGSat) (25–50 m) and National Aeronautics and Space Administration Carbon Mapper (CM-NASA) (30 m) short-wave infrared (SWIR) retrievals; fluxes were annualized and normalized by MSW throughput (t/t of CH₄ CH 4 /MSW), adopting a conservative ±(20%–50%) uncertainty envelope and lower-bound emissions for discrepancy tests. Satellite-derived emission intensities frequently exceeded CDM-reported fugitive values, reaching order-of-magnitude ratios at several sites. Composition-based scaling indicates higher intrinsic generation potential in Brazil (45% biodegradable organics vs. ~ ∼ 40% USA baseline), implying about 0.057 t/t of CH₄ CH 4 /MSW before tropical decay effects, while an independent monitoring program from the Brazilian Ministry of Science, Technology and Innovation (MCTI) suggests much lower methane recovery ( ~ ∼ 0.009 t/t of CH₄ CH 4 /MSW) than implied by CDM reports. Overall, results show that landfill methane estimates are highly sensitive to parameter choices and data granularity, and that satellite-integrated measurement, reporting and verification (MRV) can provide scalable third-party verification and improve the credibility of methane mitigation and reporting in Brazil. These findings underscore the need for enhanced methane monitoring and recovery through the adoption of a structured national methane capture program analogous to the USA Environmental Protection Agency (EPA) Landfill Methane Outreach Program (LMOP), alongside increased investment in alternative waste management strategies, including composting of source-separated organics and waste-to-energy technologies.