Climate change will exacerbate population exposure to future heat waves in the China-Pakistan economic corridor

The China-Pakistan Economic Corridor (CPEC) is a climate change-sensitive region, facing frequent and intense heat waves (HWs). The CPEC is expected to experience a simultaneous increase in population and temperature in the coming decades, which could exacerbate human exposure to future HWs. However, it is unknown how much of the population would likely be exposed to HWs in the CPEC under changing climate. This study used the Coupled Model Inter-comparison Project 6 (CMIP6) models and population projections to estimate population exposure to daytime, nighttime, and compound HWs in the CPEC during 2071–2100, relative to 1985–2014 under four Shared Socioeconomic Pathways (SSPs). The results indicate that the study region will probably experience the highest number of nighttime HWs, followed by daytime and compound HWs in the northern, southwestern, and southern parts of the CPEC. The largest population would likely be exposed in the eastern and southwestern CPEC under SSP3-70|SSP3, followed by SSP5-8.5|SSP5, SSP2-4.5|SSP2, and SSP1-2.6|SSP1. The results reveal that the climatic and interactive effects could significantly escalate the population exposure to future HWs in the CPEC. The probability of 2015-HWs-like events and population exposure to such extremes would probably be higher in the eastern CPEC. The return period of 2015-HW-like events would decrease, which indicates their frequent occurrence under the selected SSPs. The findings of the study highlight the need for urgent actions to limit greenhouse gas emissions and to adopt effective adaptation measures in order to avoid the negative consequences of HWs on the local population in the future.