Human-induced climate change intensifies spatially compounding fire weather extremes across European countries

Intensifying fire-weather extremes increasingly threaten Europe, with recent wildfires linked to human-induced climate change. Yet, little is known about spatially compounding fire danger events—days when multiple regions simultaneously face extreme fire weather—which can trigger widespread fires and potentially overwhelm shared EU firefighting resources, amplifying impacts. Here, we analyse spatially compounding fire danger by combining burned area observations (2001–2015), ERA5-based Fire Weather Index (1950–2024), and CMIP6 climate simulations. We reveal that cross-country correlations in fire weather strongly enhance the likelihood of extremely widespread fire weather, with long-lasting compound hot-dry conditions acting as key meteorological drivers. The spatial extent of extreme fire weather has expanded markedly over the past three decades, primarily due to rising temperature and the associated decline in relative humidity. On average over the past decade, human-induced climate change contributed to the annual-maximum extent of European land synchronously experiencing extreme fire weather by 14.8% (4.8–25.6%, interquartile range across models). These results highlight the need for coordinated European adaptation to the growing potential for large-scale wildfires.