Rising compound hot-dry extremes engendering more inequality in human exposure risks

Abstract

Compound hot-dry events, with their amplified negative impacts on ecosystems and societies, are attracting growing attention. This study investigates the global-scale inequality and risks of hot-dry compound events under various shared socioeconomic pathways (SSP) scenarios, considering hazards, exposure, and vulnerability. Results show a worldwide increase in hot-dry extreme events and population exposure by mid-century (2041–2070), with variations among scenarios and regions. Climate factors are identified as the primary contributors to future changes in population exposure. SSP1-2.6 shows lower risks than SSP5-8.5 notably. Spatially, ASIA and the Middle East and Africa (MAF) will likely face higher exposure risks due to large populations, lower income levels and aging demographics, which amplify climate impacts. Under SSP3-7.0, rapid population growth introduces greater uncertainty in exposure estimates, particularly in ASIA, MAF, Latin America and the Caribbean (LAM). Aging populations, especially under SSP3-7.0 and SSP5-8.5 scenarios, exacerbate exposure risks through climate-demographic interactions.