5 million deaths a year linked to abnormal temperatures from climate crisis

About 10 per cent of global deaths can be attributed to hot and cold temperatures, finds study

Steam and exhaust seen on a cold winter day on 6 January 2017 in Oberhausen, Germany (Getty Images)

Over five million extra deaths each year could be due to abnormal hot and cold extremes caused by the ongoing climate crisis, according to one of the largest studies of mortality and temperature changes in over 40 countries, analysing close to two decades of data.

According to the findings published in the journal The Lancet Planetary Health, the five million deaths account for 9.43 per cent of global deaths attributed to cold and hot temperatures.

This are about 74 excess deaths for every 100,000 people, most being caused by cold exposure, according to the study.

The research found that deaths associated with hot temperatures increased in all regions from the turn of the millennium, suggesting that global warming due to the climate crisis will make this mortality figure worse in the future.

The scientists, including Yuming Guo from Monash University in Australia, Dr Shanshan Li and Dr Qi Zhao from Shandong University in China, said more than half the excess deaths linked to cold and hot temperatures occurred in Asia.

“Our study found that more than half the excess deaths occurred in Asia, and especially in low-lying and crowded coastal cities in eastern and southern Asia,” they wrote in the study.

Eastern Europe experiences the highest excess death rates per 100,000 linked to heat exposure, the researchers said, adding that sub-Saharan Africa had the highest death rates per 100,000 associated with exposure to cold.

In the study, scientists analysed mortality and temperature data across the world from 2000 to 2019, a period when global temperatures rose by 0.26C per decade.

While previous research looked at temperature-related mortality within a single country or region, the scientists said this is the “first study to get a global overview of mortality” during the hottest period since the pre-Industrial era.

An earlier large-scale study, published in The Lancet in 2015, assessed mortality in about 15 countries and estimated that 7.7 per cent of deaths were related to cold and hot temperatures.

“Importantly, we used 43 countries’ baseline data across five continents with different climates, socioeconomic and demographic conditions and differing levels of infrastructure and public health services, so the study had a large and varied sample size, unlike previous studies,” Mr Guo said about the current research in a statement.

Based on the analysis, the scientists said eastern Europe and sub-Saharan Africa have the highest heat and cold-related excess death rates.

According to the study, cold-related deaths decreased 0.51 per cent from 2000 to 2019, while heat-related deaths increased 0.21 per cent, leading to a reduction in net mortality due to cold and hot temperatures.

The largest decline of net mortality was in southeast Asia, while there was temporal increase in south Asia and Europe, the study noted.

Based on the analysis, Mr Guo said global warming may “slightly reduce the number of temperature-related deaths, largely because of the lessening in cold-related mortality, however in the long-term, climate change is expected to increase the mortality burden because hot-related mortality would be continuing to increase (sic).”

The findings, according to the scientists, highlight “the importance of taking data from all points of the globe, in order to get a more accurate understanding of the real impact of non-optimal temperatures under climate change.”

They believe understanding similar geographic patterns of temperature-related mortality may lead to better international collaboration in developing policies and strategies targeting mitigation of the climate crisis and adaptation.