Escalating socioeconomic exposure to extreme heat in China: A CMIP6-based analysis of future heatwaves across regions and scenarios

Abstract

The future increased frequency and intensity of heat waves (HWs) across China will exacerbate adverse effects on society and the environment. However, changes in socioeconomic exposure remain underexplored. In this study, climate model outputs from the Coupled Model Intercomparison Project Phase 6 (CMIP6), together with population and gross domestic product (GDP) projections were used to investigate projected heat stress and socioeconomic exposure across China and its eight subregions under four shared socioeconomic pathway (SSP) scenarios (SSP1–2.6, SSP2–4.5, SSP3–7.0, and SSP5–8.5) over three periods (2021–2040, 2051–2070, and 2081–2100). Our results indicate a consistent upward trend in the Universal Thermal Climate Index (UTCI) across all scenarios, with intensifying increases over time, peaking at > 6 °C. This suggests a continuous increase in the number of extreme heat events (EHEs) in China. Population exposure to EHEs across the four UTCI thresholds (> 26 °C, > 32 °C, > 38 °C, and > 46 °C) shows an increasing trend. Projections indicate a ∼14-fold increase nationwide, 500-fold increase in Northwest China (NWC), and a 1000-fold in Southwest China (SWC2) under SSP5–8.5 by 2081–2100 compared with current levels. The eastern and southeastern regions, especially the Yangtze River and Pearl River Delta, show significant GDP exposure increases under SSP3–7.0 and SSP5–8.5. Population exposure is mainly driven by climatic effects under severe scenarios, whereas GDP exposure is influenced by interaction effects, particularly under SSP5–8.5 and during the 2090s. This study’s findings offer actionable insights for targeted adaptation in China’s diverse geographies.

Keywords

Heat wave / Universal thermal climate index / Climate change / Population exposure / Gross domestic product exposure

CRediT authorship contribution statement

Shan Zou: Writing – review & editing, Writing – original draft, Methodology, Investigation, Formal analysis, Funding acquisition, Conceptualization. Fubao Sun: Writing – review & editing, Supervision, Conceptualization. Philippe De Maeyer: Writing – review & editing. Tim Van De Voorde: Writing – review & editing. Weili Duan: Writing – review & editing.

Declaration of competing interests

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Acknowledgements

This study was supported by the Third Xinjiang Scientific Expedition Program (Grant No. 2023xjkk0101), and the National Youth Talent Project (Grant No. E4150103). We would like to express our gratitude to all of the authors who freely and publicly released the data used in this study. The base map used in this study is the standard map (No. GS(2025)0904) downloaded from the Standard Map Service website of the National Administration of Surveying, Mapping and Geographic Information of China.

Supplementary materials

Supplementary material associated with this article can be found, in the online version, at doi:10.1016/j.geosus.2025.100374.

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