Assessing future heat stress across China: combined effects of heat and relative humidity on mortality

Guwei Zhang; Ling Han; Jiajun Yao; Jiaxi Yang; Zhiqi Xu; Xiuhua Cai; Jin Huang; Lin Pei

doi:10.3389/fpubh.2023.1282497

Assessing future heat stress across China: combined effects of heat and relative humidity on mortality

Front Public Health. 2023 Oct 3:11:1282497. doi: 10.3389/fpubh.2023.1282497. eCollection 2023.

Authors

Guwei Zhang^{1

2

3}, Ling Han⁴, Jiajun Yao⁵, Jiaxi Yang^{1

2

3}, Zhiqi Xu^{1

2

3}, Xiuhua Cai⁶, Jin Huang⁷, Lin Pei^{1

2

3}

Affiliations

¹ Institute of Urban Meteorology, China Meteorological Administration, Beijing, China.
² Key Laboratory of Urban Meteorology, China Meteorological Administration, Beijing, China.
³ Key Laboratory of Transforming Climate Resources to Economy, China Meteorological Administration, Chongqing, China.
⁴ National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China.
⁵ Shengzhou Meteorological Bureau, Shaoxing, China.
⁶ Chinese Academy of Meteorological Sciences, Beijing, China.
⁷ Chifeng City Center Hospital Ningcheng County, Chifeng, China.

Abstract

This study utilizes China's records of non-accidental mortality along with twenty-five simulations from the NASA Earth Exchange Global Daily Downscaled Projections to evaluate forthcoming heat stress and heat-related mortality across China across four distinct scenarios (SSP1-2.6, SSP2-4.5, SSP3-7.0, and SSP5-8.5). The findings demonstrate a projected escalation in the heat stress index (HSI) throughout China from 2031 to 2100. The most substantial increments compared to the baseline (1995-2014) are observed under SSP5-8.5, indicating a rise of 7.96°C by the year 2100, while under SSP1-2.6, the increase is relatively modest at 1.54°C. Disparities in HSI growth are evident among different subregions, with South China encountering the most significant elevation, whereas Northwest China exhibits the lowest increment. Projected future temperatures align closely with HSI patterns, while relative humidity is anticipated to decrease across the majority of areas. The study's projections indicate that China's heat-related mortality is poised to surpass present levels over the forthcoming decades, spanning a range from 215% to 380% from 2031 to 2100. Notably, higher emission scenarios correspond to heightened heat-related mortality. Additionally, the investigation delves into the respective contributions of humidity and temperature to shifts in heat-related mortality. At present, humidity exerts a greater impact on fluctuations in heat-related mortality within China and its subregions. However, with the projected increase in emissions and global warming, temperature is expected to assume a dominant role in shaping these outcomes. In summary, this study underscores the anticipated escalation of heat stress and heat-related mortality across China in the future. It highlights the imperative of emission reduction as a means to mitigate these risks and underscores the variances in susceptibility to heat stress across different regions.

Keywords: China; NEX-GDDP-CMIP6; future projections; heat stress; heat-related mortality.

MeSH terms

China / epidemiology
Climate Change*
Heat-Shock Response*
Humidity
Temperature

Grants and funding

The author(s) declare financial support was received for the research, authorship, and/or publication of this article. Financial support for this research is provided by several sources, including the “Unveiling and Commanding” from CMA (No. CMAJBGS202207), the National Natural Science Foundation of China (Grant Nos. 42205170 and 42305200), the CMA Key Open Laboratory of Transforming Climate Resources to Economy (No. 2023009), the Public Health Service Capability Improvement Project from the National Health Commission of the People’s Republic of China (No. 2100409034), the Key Innovation Team of China Meteorological Administration (No. CMA2022ZD09), and the Open Grants of the State Key Laboratory of Severe Weather (No. 2023LASW-B19), and the BMBKJ202201005 from Beijing Meteorological Service.