A shorter, sharper rainy season amplifies California wildfire risk

Recent fire and climate science research has demonstrated a clear link between worsening California wildfires and climate change, mainly though the vegetation-drying effect of rising temperatures and shifting precipitation seasonality. New work by Lukovic et al. (2021) explores observed changes in California's autumn precipitation in greater detail, finding that the rainy season has indeed become progressively delayed and that the "sharpness" of California precipitation seasonality has increased.

These precipitation shifts have important implications for the region's ecology and wildfire risk, as they increase the degree of temporal overlap between extremely dry vegetation conditions and fire-promoting downslope winds in late autumn. Both of these observed shifts are consistent with climate model projections for the region's future, suggesting that recent trends may offer an early preview of larger changes to come.