Divergent trends in demographic and socioeconomic inequalities of global wildfire and compound hazard exposures

Heatwaves, wildfires, aerosol pollution, and their compound occurrences are increasingly recognized as severe threats with profound societal and environmental consequences. However, their global ptterns and associated exposure inequalities remain insufficiently understood. On the basis of multisource satellite and reanalysis data, we explore spatiotemporal variations of individual and compound hazards of heatwaves, wildfires, and aerosol pollution globally over 2002–2023. Exposure inequality is further assessed from both demographic and socioeconomic perspectives. Results reveal a widespread increase in heatwaves and related compound events, particularly during boreal summer and autumn, while wildfires and related compound events exhibit greater spatial and temporal heterogeneity. Despite less frequent, compound events lead to significantly greater exposure inequality. Demographic inequality generally declines, while socioeconomic disparities intensify over the past two decades. Economically disadvantaged regions are disproportionately facing higher and faster-growing exposure. These findings underscore the urgent need to incorporate compound hazard risk and inequality into climate adaptation and public health strategies.