Rapid summer methane emission decline in high-latitude plains linked to 2021 drought

In summer 2021, the northern high-latitude plains (NHP) of the Eurasian continent endured their most severe drought in nearly two decades, with important implications for regional methane emissions. Using the Global ObservatioN-based system for monitoring Greenhouse GAses for methane (GONGGA-CH4) inversion system along with a merged Greenhouse gases Observing SATellite (GOSAT) + TROPOspheric Monitoring Instrument (TROPOMI) dataset, we quantified drought impacts on methane emissions. Independent validation confirmed the system’s high accuracy, revealing a 20% summer emission reduction in NHP during 2021 compared to baseline years. This reduction is primarily attributed to a decrease in liquid water content, which strongly affected wetland emissions. The underlying causes were heightened evaporation and the presence of a blocking high-pressure system within the atmospheric circulation. These findings highlight the profound impact of summer droughts on methane emissions in high-latitude regions, and emphasize the critical importance of integrating diverse data sources to refine methane emission estimates. The 2021 drought across northern high-latitude Eurasia reduced summer methane emissions by 20%, mainly from wetlands due to lower liquid water content, according to an analysis using a greenhouse gas monitoring inversion system and a merged satellite dataset.