Escalating burned area in western US forests punctuated by the 2020 fire season has heightened the need to explore near-term macroscale forest-fire area trajectories. As fires remove fuels for subsequent fires, feedbacks may impose constraints on the otherwise climate-driven trend of increasing forest-fire area. This study tests how fire-fuel feedbacks moderate near-term (2021-2050) climate-driven increases in forest-fire area across the western US. Assuming constant fuels, climate-fire models project a doubling of forest-fire area compared to 1991-2020. Fire-fuel feedbacks only modestly attenuate the projected increase in forest-fire area. Even models with strong feedbacks project increasing interannual variability in forest-fire area and more than a two-fold increase in the likelihood of years exceeding the 2020 fire season. Fuel limitations from fire-fuel feedbacks are unlikely to strongly constrain the profound climate-driven broad-scale increases in forest-fire area by the mid-21st century, highlighting the need for proactive adaptation to increased western US forest-fire impacts.

John T. Abatzoglou, David S. Battisti, A. Park Williams, Winslow D. Hansen, Brian J. Harvey, Crystal A. Kolden