Science Source

Michael Goss, Daniel L Swain, John T Abatzoglou, Ali Sarhadi, Crystal Kolden, A Park Williams, Noah S Diffenbaugh

Environmental Research Letters

Published date March 26, 2020

Climate change is increasing the risk of extreme autumn wildfire conditions across California

Shows that state-wide increases in autumn temperature (~1 ˚C) and decreases in autumn precipitation (~30%) over the past four decades have contributed to increases in aggregate fire weather indices (+20%)
Finds, as a result, the observed frequency of autumn days with extreme (95th percentile) fire weather – which we show are preferentially associated with extreme autumn wildfires – has more than doubled in California since the early 1980s
Finds an increase in the climate model-estimated probability of these extreme autumn conditions since ~1950, including a long-term trend toward increased same-season co-occurrence of extreme fire weather conditions in northern and southern California
Climate model analyses suggest that continued climate change will further amplify the number of days with extreme fire weather by the end of this century, though a pathway consistent with the UN Paris commitments would substantially curb that increase