Mortality caused by heatwaves in China has increased since 1979

Since summer of 2022 began, China has been sweltering under the worst heatwave in decades. A number of people in Zhejiang, Henan, Jiangsu, and Sichuan provinces were diagnosed with thermoplegia, the most severe form of heatstroke, and some even died of this disease. 

In a warming world, the threat of heatwaves to human health is increasing. With its large population and vast area, China is sensitive to impact of climate change. Scientists have found it essential to study the number of deaths caused by heatwaves and their driving factors in China from 1979 to 2020. A study led by Dr. ZHAO Liang at the CAS Institute of Atmospheric Physics and Prof. HUANG Cunrui at the Vanke School of Public Health and Wellness, Tsinghua University, focused on the spatial and temporal variation of heatwaves-related human deaths in China over the past 42 years. They also explored the relative contributions of drivers such as heatwaves exposure, population growth, population aging, and baseline mortality to changes in attributable mortality.

"We found that the number of deaths caused by heatwaves in China has increased rapidly since 1979, from 3679 persons per year in the 1980s to 15,500 persons per year in the 2010s." said Dr. ZHAO. "We also found strong spatial heterogeneity across the country, with more human deaths in East and Central China."

Then what are the main drivers of the large increase in heatwaves-related deaths in China over the past four decades?

"The main drivers are the rapid increase in the frequency of heatwaves, followed by population growth, population aging, and rising baseline mortality. From the 2000s to the 2010s, these four factors accounted for 40.6%, 22.4%, 20.8%, and 16.2% of the change in attributed human deaths, respectively." Explained Prof. HUANG. 

The research team hopes this study's accurate assessment of the number of heatwaves related deaths in China and the contribution of their different drivers can help policy makers to fully understand the human health hazards of heatwaves and to develop response policies to reduce health losses from increased heatwaves exposure under climate change.