Projected Changes in Socioeconomic Exposure to Heatwaves in South Asia Under Changing Climate

Abstract The risk of heatwave events and their persistence has intensified in recent past and is expected to increase faster in future. However, the anticipated changes in socioeconomic exposure to heatwaves are still unexplored. Here, we investigate the projected heat stress and associated socioeconomic exposure across South Asia (SA) and its subregions using the newly released ensemble mean of 23 global climate models from the Coupled Model Intercomparison Project Phase 6 (CMIP6), population, and Gross Domestic Product (GDP) projections. We used two Shared Socioeconomic Pathways (SSPs), namely SSP2‐4.5 and SSP5‐8.5, and three‐time periods, that is, near‐term, midterm, and long‐term relative to the base period (1985–2005). We found that SA region has the potential for widespread changes to Wet bulb globe temperature (WBGT) of 6.5°C, which can exceed the theoretical limits of human tolerance by the mid of 21st century. The SA population's exposure significantly increases during midterm and long‐term periods by ∼ person‐hours under the SSP5‐8.5 scenario. The GDP exposure is the greatest for the same period's up to dollar‐hours under the SSP2‐4.5. Moreover, the foothills Himalayans and northern parts of Pakistan are presently unaffected by WBGT during midterm and long‐term periods under both scenarios. Among subregions (hereafter R1, R2, R3, and R4), the frequency of subdaily WBGT is projected to increase in the region R2 and R4 by ∼70% and ∼90% under the SSP2‐4.5 and SSP5‐8.5 scenarios relative to the base period. The highest upsurge in exposure is anticipated for R2, including southern Pakistan and southwestern India, followed by R1 and R3. Notably, the climate effect is more dominant than the population, whereas changes in GDP effect contribute to the total change in GDP exposure.