Smoke-weather interaction feeds extreme wildfires in Mediterranean and monsoon climate regimes

Abstract Extreme wildfires increasingly threaten human lives, infrastructure, air quality, and ecosystem services. Meteorology plays a vital role in wildfire activities, and thus the relationship between wildfire intensity and climate change has been widely studied. However, it remains unclear how fire-weather interactions affect short-term fire variability (e.g., 1–2 weeks), which in turn undermines our ability to mitigate fire disasters despite substantial progress in weather forecasting. Here we show the primacy of synoptic-scale feedbacks in driving extreme fires in both Mediterranean and monsoon climate regimes in United States West Coast and Southeastern Asia. In our modeling, radiative ef-fects of smoke aerosols tend to modify wind speed, air dryness, and rainfall, and hence substantially amplify severe air pollution by enhancing fire emissions and weakening smoke dispersion. Such fire-weather interactions form a positive feedback loop that may contribute to large increases in air-pollution mortality during extreme wildfires. Our study underscores the urgency of fundamental understanding of fire-weather interaction and points to a key opportunity for reducing extreme wildfires in populated coastal regions.