Diminished Radiative Cooling With Northward Wildfire Advance in the East Siberian Boreal Region

Abstract

Intensification of the Siberian wildfire regime is characterized by large increases in burned area above the Arctic Circle. Wildfire in boreal forests typically reduces albedo in the decades following fire, resulting in a net cooling effect. Here we quantified changes in albedo and the accompanying radiative forcing associated with a northward shift in Siberian wildfires. The radiative forcing averaged over approximately two decades post‐fire was −1.45 ± 0.56 Wm ⁻² for fires at 55–60°N but only −0.37 ± 0.74 Wm ⁻² for fires at 65–70°N. This diminished cooling effect was due to reduced tree cover and differences in post‐fire vegetation recovery with latitude. The recent poleward shift in eastern Siberian fires reduces the strength of an important negative climate feedback with implications for regional and global climate.