measurements. The methane-isotopic inversion yields total emissions of 623 585-643 Tg/y, slightly higher than the methane-only inversion. Incorporating isotopic constraints leads to a redistribution of emissions in tropical and subtropical regions. Compared with the methane-only inversion, the methane-isotopic inversion indicates that emission estimates increase by 26 -3-27 Tg/y in East Asia (primarily China), 7 -1-8 Tg/y in South Asia (primarily India), and 5 -3-10 Tg/y in central Africa, while decreasing by 5 -6-7 Tg/y in Amazon Basin and 12 -14-20 Tg/y elsewhere. This points to a stronger anthropogenic contribution to the post-2019 methane budget, including higher fossil emissions in China and slightly less wetland emissions in the Amazon Basin. The methane-isotopic inversion also alters inferred emission seasonality, showing less seasonality in China compared with the methane-only inversion, weaker coal-mine phase-out signals, and a delayed summer peak in Southeast Asia, pointing to sources missing from current inventories.
Yu et al. (Mon,) studied this question.