Smoke-weather interaction affects extreme wildfires in diverse coastal regions

Extreme wildfires threaten human lives, air quality, and ecosystems. Meteorology plays a vital role in wildfire behaviors, and the links between wildfires and climate have been widely studied. However, it is not fully clear how fire-weather feedback affects short-term wildfire variability, which undermines our ability to mitigate fire disasters. Here, we show the primacy of synoptic-scale feedback in driving extreme fires in Mediterranean and monsoon climate regimes in the West Coast of the United States and Southeastern Asia. We found that radiative effects of smoke aerosols can modify near-surface wind, air dryness, and rainfall and thus worsen air pollution by enhancing fire emissions and weakening dispersion. The intricate interactions among wildfires, smoke, and weather form a positive feedback loop that substantially increases air pollution exposure. Description Feedback promotes fire How much might interactions between wildfires and local meteorology affect short-term wildfire variability? Huang et al. show that large-scale feedbacks are an important driving force on extreme fires in the Mediterranean, the West Coast of the United States, and Southeastern Asia. Smoke aerosols trap and absorb solar energy, changing local wind and rainfall patterns and ultimately enhancing fire emissions. These interactions constitute a positive feedback that increases air pollution exposure and accelerates wildfire expansion. —HJS Wildfire smoke aerosols affect local weather and can accelerate wildfire expansion.