Wildfire smoke-weather interaction amplifies extreme fire activity and air pollution

Wildfire smoke affects local weather, creating conditions that accelerate wildfire expansion and air pollution exposure at a regional scale, according to a new study. The findings, which reveal an “unexpectedly strong” fire-weather feedback shared across diverse fire-prone regions, could be used to help inform wildfire mitigation strategies. Over the past several decades, wildfires have grown in frequency and severity worldwide. Many aspects of wildfires are determined by a region’s weather patterns. However, most previous research on the relationship between wildfires and meteorology has focused on long-term climate scales rather than short-term weather processes. What’s more, relatively little attention has been paid to elements that could impact meteorology related to fires, such as black carbon from fire smoke. To better understand how the interactions among such factors, and how weather at shorter scales, contribute to fires in the U.S. West Coast and Southeastern Asia – two fire-prone regions with dense populations – Xin Huang et al. used a coupled meteorology-chemistry model and satellite and ground-based observational datasets. They found that short-term variations in key meteorological factors such as humidity, wind speed, and precipitation are drivers of extreme wildfires in both regions. The radiative effects of black carbon aerosols released as fire smoke from individual fire events there also substantially alter local meteorology, worsening wildfire impacts on air quality. Although extreme fires in the two regions appear to be modulated by different meteorological drivers (dryness and windspeed in the U.S. West Coast and precipitation in Southeastern Asia), they share a common feedback mechanism: both are driven by the radiative effects of fire smoke. “Given the persistence and spread of wildfires and fire-weather feedback, early-stage fire suppression at preidentified amplifier regions based on near-real-time forecasting could avert some extreme wildfires,” say the authors.