Global warming increases population exposure to wildfires

Wildfires are expected to increase under warmer and drier conditions, yet little is known about their potential effects on population at global scale. Here, we developed a novel framework based on statistical wildfire model and spatial demographic data to better understand how global warming alters population exposure to wildfires throughout the world. We sought to model annual burn rate with relevant explanatory variables, such as climate, land cover, and topography to simulate historical and future wildfire frequency at global scale. To do so, we used a Generalized Additive Model combined with historical climate data and an ensemble of CMIP6 climate projections under the SSP5-8.5 scenario. We then analysed population exposure to wildfires combining population count across the wildland–urban interfaces with the simulated historical and future wildfire frequency. Our results indicate that in the present day the highest population exposure to wildfires is in southeast Asia, parts of South America and Africa, due to the large number of people living in wildland–urban interfaces with a high wildfire frequency. All other things being equal, global warming was found to increase population exposure, with an expansion of the regions with high wildfire frequency in east and south Europe, southeastern Asia, parts of North and South America. The estimated increase in population exposure may also imply potential impacts on the built environment and human health in the absence of mitigation or adaptation measures.