2019–2024 trends in African livestock and wetland emissions as contributors to the global methane rise

Abstract. 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.