Tuesday, September 06, 2022

Spatiotemporal variation of mortality burden attributable to heatwaves in China, 1979-2020

Peer-Reviewed Publication

SCIENCE CHINA PRESS

 NEWS RELEASE 

Spatiotemporal variation of attributable deaths to heatwaves in China. 

IMAGE: HEALTH RISKS OF HEATWAVES WERE CHARACTERIZED BY RAPID GROWTH, NONLINEAR TEMPORAL EVOLUTION AND EXTREMITY. NATIONALLY, THE NUMBER OF ANNUAL ATTRIBUTABLE DEATHS WAS AN AVERAGE OF 3,679 IN 1980S BUT INCREASED TO 15,500 IN 2010S. TAKING A 5-YEAR MOVING AVERAGE, IT TOOK 2.8 YEARS FOR EVERY INCREASE OF 1,000 ANNUAL HEATWAVE-RELATED DEATHS FROM 1980S TO 2000S, BUT JUST ONE YEAR FOR THE SAME INCREASE TO OCCUR IN 2010S. ALSO, THE ATTRIBUTABLE DEATHS REACHED A HIGHEST RECORD OF 26,486 IN 2017, FOLLOWED BY THE SECOND 21,219 IN 2019 AND THE THIRD 20,431 IN 2013. REGIONALLY, EAST AND CENTRAL CHINA HAD THE LARGEST NUMBER OF ATTRIBUTABLE DEATHS IN GENERAL, ACCOUNTING FOR MORE THAN 50% OF DEATHS NATIONWIDE. AMONG THE PROVINCES, DEATHS ASCRIBED TO HEATWAVES WERE HIGHEST IN SHANDONG, FOLLOWED BY HENAN, HEBEI AND JIANGSU. A-D, THE NUMBER OF ATTRIBUTABLE DEATHS TO HEATWAVES IN GRID DURING THE PAST FOUR DECADES. E, ATTRIBUTABLE DEATHS TO HEATWAVES IN CHINA FROM 1979 TO 2020. THE SOLID LINE SHOWS THE ESTIMATED NUMBER OF ATTRIBUTABLE DEATHS TO HEATWAVES; GREY AREAS SHOW THE 95% CONFIDENCE INTERVALS; THE HORIZONTAL DASHED LINE SHOWS THE AVERAGE ANNUAL DEATHS IN 1980S, 1990S, 2000S, 2010S. F, CHANGES IN ATTRIBUTABLE DEATHS TO HEATWAVES IN 2010S RELATIVE TO THE BASELINE PERIOD OF 1980-2009. AD, ATTRIBUTABLE DEATHS TO HEATWAVES. THE MAP NO. IS GS(2019)1673. ART BY HUIQI CHEN. view more 

CREDIT: ©SCIENCE CHINA PRESS

This study is led by Dr. Cunrui Huang (Vanke School of Public Health, Tsinghua University). Heatwaves impose heavy disease burden by increasing the risk of mortality and morbidity, which has been exacerbated worldwide under climate change. "In China, evidence documenting the impact of heatwaves on the number of attributable deaths, spatiotemporal variations and their driving factors is still limited, hindering the understanding of dangerous heatwaves. " Huang says.

Huang, together with his group member Chen and meteorological expert Zhao, sought to identify what was the spatial and temporal trends of heatwave-attributable deaths in China over the past four decades. The team performed event-based attributable loss estimation to quantify the gridded attributable deaths.

The team found that health risks of climate change were characterized by rapid growth, nonlinear evolution and extremity. The attributable deaths to heatwaves in China have increased dramatically by four times in the past four decades, with the rising trends becoming more apparent in the recent decade but some fluctuations among individual years. Regionally, east and central China had the largest number of attributable deaths in general, accounting for more than 50% of deaths nationwide. Among the provinces, deaths ascribed to heatwaves were highest in Shandong, followed by Henan, Hebei and Jiangsu.

The researchers also decomposed the driving factors to changes in attributable deaths. The increase in attributable deaths to heatwaves in China over time was primarily due to increased heatwave exposure, followed by population growth, population aging and the mounting baseline mortality. Notably, population aging has played an increasingly important role in attributable deaths over time. This work could serve important information for policy-makers to develop effective climate mitigation and adaptation measures in response to increasing heatwaves, especially for the most vulnerable elderly populations.

See the article:

Spatiotemporal Variation of Mortality Burden Attributable to Heatwaves in China, 1979-2020

https://doi.org/10.1016/j.scib.2022.05.006

Mortality caused by heatwaves in China has increased since 1979


Peer-Reviewed Publication

INSTITUTE OF ATMOSPHERIC PHYSICS, CHINESE ACADEMY OF SCIENCES

Heatwaves 

IMAGE: HEATWAVES SWEEPS THROUGH NORTHERN CHINA. PHOTO TAKEN IN BEIJING ON JULY 20. view more 

CREDIT: LIANG ZHAO

Since the beginning of the summer in 2022, 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. Researchers led by Liang Zhao from the Institute of Atmospheric Physics of the Chinese Academy of Sciences and Cunrui Huang from Tsinghua University investigated the spatial and temporal variation of heatwaves-related human deaths in China from 1979 to 2020.

The study was published in Science Bulletin.

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 3,679 persons per year in the 1980s to 15,500 persons per year in the 2010s," said 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," said 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 human health hazards of heatwaves and to develop response policies to reduce health losses from increased heatwaves exposure under climate change.

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