Anthropogenic emissions and urbanization increase risks of compound hot extremes in cities

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Most areas of the world are experiencing increasing and intensifying hot extremes. Heat-related health consequences vary with the characteristics of the exposed landscape and types of hot extreme.

Despite mounting evidence of detrimental health impacts from or nights due to their and/or long duration, their occurrence in close sequence—a compound hot extreme—has received little attention but may bear large health risks.

A new study published in Nature Climate Change revealed how the compound (day-night sustained) hot extremes affect , as well as the drivers of observed changes, and future risk in cities of eastern China.

The study showed that compound hot extremes were more dangerous than solely daytime or nighttime heat, especially to female and older urban residents.

Urban compound hot extremes across eastern China increased by 1.76 days per decade from 1961 to 2014, and the fingerprints of urbanization and anthropogenic emissions (e.g., and aerosols) could be detected.

Their attributable fractions were estimated as 0.51 (urbanization), 1.63 (greenhouse gases) and -0.54 (other anthropogenic forcings) days per decade. Future emissions and urbanization would make these compound events two-to-five times more frequent (2090s vs. 2010s), leading to a threefold-to-sixfold growth in urban population exposure.

"Our study reveals that the public health risks from anthropogenic increases in compound hot extremes have been increasing and will continue to increase over cities in eastern China." Said Dr. WANG Jun from the Institute of Atmospheric Physics (IAP) of the Chinese Academy of Sciences, the first author of the study.

According to the study, the uncovered age-specific vulnerability to compound hot extremes implies further elevated health burdens due to rapid aging of the urban population there.

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Urbanization magnified nighttime heat waves in China

More information: Jun Wang et al, Anthropogenic emissions and urbanization increase risk of compound hot extremes in cities, Nature Climate Change (2021). DOI: 10.1038/s41558-021-01196-2
Journal information: Nature Climate Change

Citation: Anthropogenic emissions and urbanization increase risks of compound hot extremes in cities (2021, November 4) retrieved 3 October 2022 from
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