Socio-demographic factors shape mortality risk linked to compound drought-heatwave events under climate change in China

r warming scenarios in China d Exposures to CDHWs elevate mortality risk, with women facing a higher risk d Socio-demographic factors will significantly influence future CDHW-related deaths d Remarkable regional inequalities in health impacts of CDHWs exist in China Authors Xin Yao, Ying Qu, Liqiang Zhang,..., Suhong Liu, Qihao Wang, Chenghu Zhou Correspondence zhanglq@bnu.edu.cn (L.Z.), baichen-slhr@ruc.edu.cn (C.B.), zhouch@lreis.ac.cn (C.Z.) In brief Anthropogenic warming has increased the frequency of simultaneous drought and heatwave occurrences, further intensifying CDHW events globally. However, the CDHW-mortality relationship and the effects of sociodemographic factors remain poorly understood. We find that the increasing frequency, duration, and severity of CDHWs all elevate the mortality risk. Notably, population aging and changes in baseline mortality rates have a greater impact on the CDHW-related mortality burden than the level of warming under climate change. Yao et al., 2024, One Earth 7, 1–15 November 15, 2024 ª 2024 Elsevier Inc. All rights are reserved, including those for text and data mining, AI training, and similar technologies. https://doi.org/10.1016/j.oneear.2024.09.016 ll Article Socio-demographic factors shape mortality risk linked to compound drought-heatwave events under climate change in China Xin Yao,1 Ying Qu,1 Liqiang Zhang,1,7,* Ashok K. Mishra,2 Jiabo Yin,3 Ruiqiang Ding,1 Jing Yang,1 Chen Bai,4,* Lei Zhang,1 Mengting Li,4 Pan Liu,3 Jintai Lin,5 Qiwei Yu,1 Suhong Liu,1 Qihao Wang,1 and Chenghu Zhou 6,* 1Faculty of Geographical Science, Beijing Normal University, Beijing 100875, China 2Zachry Department of Civil & Environmental Engineering, Texas A&M University, College Station 77843, TX, USA 3State Key Laboratory of Water Resources Engineering and Management, Wuhan University, Wuhan, Hubei 430072, China 4School of Labor and Human Resources, Renmin University of China, Beijing 100872, China 5Laboratory for Climate and Ocean-Atmosphere Studies, Department of Atmospheric and Oceanic Sciences, School of Physics, Peking University, Beijing 100871, China 6Institute of Geographical Science and Natural Resources, Chinese Academy of Sciences, Beijing 100101, China 7Lead contact *Correspondence: zhanglq@bnu.edu.cn (L.Z.), baichen-slhr@ruc.edu.cn (C.B.), zhouch@lreis.ac.cn (C.Z.) https://doi.org/10.1016/j.oneear.2024.09.016 SUMMARY Droughts and heatwaves have far-reaching impacts on human health, and their compound effects are more severe. However, our understanding of the impact of compound drought-heatwave (CDHW) on mortality risk, which is a key input for policy prioritization to protect vulnerable populations, remains limited, particularly considering socio-demographic factors such as baseline mortality reductions, population size changes, and aging. Here, we project future changes in CDHW and associated mortality in China under three Shared Socioeconomic Pathways (SSPs). Under the highest emission scenario (SSP5-8.5), CDHW exposures led to 11.88 (95% confidence interval [95%CI], 8.77–14.80) million premature deaths among Chinese individuals aged 65 years and older by 2100. Notably, even under the least warming pathway (SSP1-2.6), deaths increase due to the expanding size of vulnerable populations. Population aging and baseline mortality changes are more influential in shaping future mortality risks than CDHW exposure levels. Our findings provide valuable insights into understanding and planning for future risk.