Increased Aerosols From Siberian Wildfires Buffered Arctic Warming During 2013–2019

Abstract During 2013–2019, global aerosols, influenced by regional clean air actions and wildfires, changed significantly. Clean air actions in China, Europe, and North America reduced anthropogenic aerosols, whereas Siberia experienced increased wildfire aerosols due to local warm and dry conditions. South Asia exhibited mixed trends with increased emissions of sulfur dioxide (SO 2 ) and decreased carbonaceous aerosols. Using the Community Earth System Model version 1 (CESM1), this study investigates Arctic climate responses to these regional aerosol changes. Reductions in aerosols from China and Europe‐North America resulted in Arctic warming effects of +0.18°C and +0.16°C, respectively, while changes in South Asian aerosols had a relatively small influence on Arctic climate. Increased aerosols from Siberian wildfires induced an Arctic cooling effect of −0.84°C, outweighing the warming from reduced anthropogenic aerosols. These cooling/warming effects are primarily attributed to changes in northward heat transport driven by aerosol changes outside the Arctic, rather than Arctic local radiative forcing. This research highlights the relationship between regional aerosols and Arctic climate, emphasizing a negative feedback mechanism via which increased Siberian wildfire aerosols, amidst accelerated warming in the Arctic Siberia, buffer the Arctic warming. It also implies that future Arctic warming could amplify Siberian wildfires, potentially reinforcing this negative feedback.