Wildfire risk for global wildland–urban interface areas

Intensifying wildfires and human settlement expansion have placed more people and infrastructure at the wildland–urban interface (WUI) areas under risk. Effective wildfire management and policy response are needed to protect ecosystems and residential communities; however, maps containing spatially and temporally explicit information on the distribution of WUI areas are limited to certain countries or local regions, and global WUI patterns and associated wildfire exposure risk therefore remain unclear. Here we generated the global WUI data layers for the 2020 baseline and the 1985–2020 time series by integrating fine-resolution housing and vegetation mapping. We estimated the total global WUI area to be 6.62 million km2. Time-series analysis revealed that global WUI areas increased by 12.56% between 1985 and 2020. By overlapping 2001–2020 wildfire burned area maps and fine-resolution population datasets, our analysis uncovered that globally, 7.07% (12.54%) of WUI areas housing 4.47 million (10.11 million) people are within a 2,400 m (4,800 m) buffer zone of wildfire threat. Regionally, we found that the United States, Brazil, China, India and Australia account for the majority of WUI areas, but African countries experience higher wildfire risk. Our quantification of global WUI spatiotemporal patterns and the associated wildfire risk could support improvement of wildfire management. Using decades of high-resolution mapping, this study tracks the land area of the wildland–urban interface that is exposed to fire risk, finding increases in both area and risk in multiple locations globally.