Increasing Future Global Compound Heat Flash Droughts and Socioeconomic Exposure

Compound heat flash droughts (CHFDs) can severely impact human society. However, the spatiotemporal evolution and socioeconomic impacts under future scenarios remain poorly understood. Here, we conduct a global assessment of spatiotemporal patterns and socioeconomic exposure of CHFDs using reanalysis data (1950–2024) and future projections from eight climate models under three scenarios. Under SSP2‐4.5, CHFD frequency increases across over two‐thirds of the global land area, with a mean increase of 0.22 events per decade. In the long‐term future (2071–2100), high‐frequency CHFDs are concentrated in northwestern South America (NWS), the South American monsoon (SAM) region, and Southeast Asia (SEA), whereas stronger severity is most pronounced in mid‐ to high‐latitude regions, such as western Siberia. The frequency in NWS reaches approximately 20 events per decade under SSP2‐4.5, nearly 4.3 times the historical level. Under SSP2‐4.5, population and gross domestic product (GDP) exposure reach 49.23% and 48.29%, respectively, by the early 2090s (i.e., 0.49 and 0.48 events per capita and per unit of GDP), whereas NWS, SAM, SEA, and Madagascar together account for approximately 26.5% of global exposure in the long‐term future. Decomposition reveals that changes in future socioeconomic exposure are dominated by the climate effect. Upper‐middle‐income regions exhibit the highest socioeconomic exposure, followed by low‐income regions. In the long‐term future, population and GDP exposure in upper‐middle‐income regions are more than twice those in high‐income regions. Our findings indicate intensifying socioeconomic impacts of CHFDs, coupled with widening regional disparities, underscoring the need for region‐specific adaptation and risk‐management strategies, especially in emerging economies.