2019–2024 Trends in African Livestock and Wetland Emissions As Contributors to the Global Methane Rise

The African continent has been recognized as a major driver of the recent rise in atmospheric methane, but the causes are not well understood. Here we use blended TROPOMI + GOSAT satellite observations of methane to quantify and attribute African emission trends over August 2018-December 2024. We do this with monthly analytical inversions, optimizing surface fluxes at 50 km resolution on the continental scale and using two alternative bottom-up wetland emission models (WetCHARTs-CYGNSS and LPJ-EOSIM-MERRA2) as prior estimates. Our best estimate of total surface fluxes from Africa over the 2019-2024 period is 71-72 Tg a(-1) depending on the choice of prior wetland emission estimate, including 28-32 Tg a(-1) from wetlands and 23-25 Tg a(-1) from livestock. We find that the bottom-up models greatly underestimate wetland emissions in South Sudan and Lake Chad and greatly overestimate emissions in the Congo Basin. Annual methane surface fluxes from Africa increased by 19-21 Tg a(-1) over 2019-2024, contributing 27 % of the global emission increase in 2019-2021 and continuing to increase after 2021 even as global emissions decreased. The 2019-2024 increase in African emissions included 11 Tg a(-1) from livestock, 4.3-5.7 Tg a(-1) from wetlands, and 2.5-2.8 Tg a(-1) from waste. The increase in livestock emissions was steady while wetland emissions surged in 2020 and 2024. Previous studies attributed uncertainties in bottom-up wetland data to poor information on inundation extent, but we find that the CYGNSS satellite inundation data match the spatial, seasonal, and interannual patterns of our optimized wetland emissions.