Overview
- Model reconstructions for 2019–2023 attribute about 80% of the year‑to‑year change in methane growth to a drop in hydroxyl radicals during 2020–2021, with recovery in 2022–2023.
- An extended La Niña increased emissions from wetlands and inland waters, especially in tropical Africa and Southeast Asia, with additional rises in the Arctic and a 2023 decline in South America during El Niño‑related drought.
- Atmospheric methane rose by roughly 55 ppb from 2019 to 2023 to a record ~1921 ppb, with growth peaking near 16.2 ppb per year before easing to ~8.6 ppb per year in 2023.
- Multiple atmospheric inversions constrained by NOAA surface data and GOSAT satellite observations, plus isotopic evidence, indicate microbial sources dominated the surge, while fossil fuel and wildfire contributions were minor.
- Researchers highlight gaps in bottom‑up wetland and inland‑water models and call for improved monitoring and process representation to better inform mitigation strategies such as the Global Methane Pledge.