Climate-induced variations in global severe fire weather conditions

Surface weather conditions are a major drivers of wildland fire size and intensity. Climatic changes over the last four decades are thought to be influencing these burning conditions both regionally and globally but few studies have comprehensively explored how climatic changes may be affecting fire weather severity during the fire season. Here we explore how these climatic changes impact two metrics of wildland fire weather: the weather-mediated length of the fire season and the within-season fire weather severity. We show that these metrics are strong predictors of burned area across the Western US, Western Europe and other fire adapted global ecosystems. We leverage these two metrics to describe changes in fire season length and severity across the globe in an effort to map areas that are experiencing significant changes in both fire weather season length and fire weather severity. These results will help us better understand how climatic variations are manifesting themselves as tangible changes in observed fire activity and it will improve our understanding of the complex interactions between long-term climatic changes, short-term weather variations and wildland fire-induced carbon cycle feedbacks.