Over 5m deaths annually linked to extreme weather

A groundbreaking study led by scientists from China and Australia has found that more than 5 million additional deaths a year globally could be attributed to extreme weather caused by climate change.

The study found that deaths related to hot temperatures increased in all regions from 2000 to 2019, indicating that global warming due to climate change will make this mortality figure worse in the future.

The findings come at a time when many parts of the world better known for their cold climates have been experiencing record heat waves from Canada to Antarctica.

Nordic countries registered near-record temperatures recently, including highs of 34 C in some places. The city of Kevo in the north of Lapland, near the border with Norway, recorded highs of 33.6 C on July 4, the hottest day since 1914 after records began in 1844.

The Nordic heat wave follows similar events in southwestern Canada and the American northwest, where intense heat waves recently killed over 600 people.

Experts and officials fear that the catastrophic conditions, fueled by the climate crisis, will only get worse in the coming months.

On Thursday, an international research team led by public health experts Guo Yuming and Li Shanshan from Australia's Monash University and Zhao Qi of Shandong University published a paper in The Lancet Planetary Health journal, in which they looked at mortality and temperature data across the world from 2000 to 2019, a period when global temperatures rose by 0.26 C every 10 years.

The study, the first to definitively link above and below optimal temperatures to annual increases in mortality, found that 9.43 percent of deaths globally could be attributed to high and low temperatures. That equates to 74 additional deaths for every 100,000 people, with most deaths caused by cold exposure.

The data reveals geographical differences on the impact of non-optimal temperatures on mortality, with Eastern Europe and sub-Saharan Africa having the highest heat-and cold-related excess death rates.

Cold-related deaths fell 0.51 percent from 2000 to 2019, while heat related deaths rose 0.21 percent, leading to a reduction in net mortality due to cold and hot temperatures.

The largest decline of net mortality occurred in Southeast Asia, while there was a temporal increase in South Asia and Europe.

Long-term impact

Guo, a professor in Monash University's School of Public Health and Preventive Medicine, said this shows 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 heat-related mortality would continue to increase," Guo said.

He also said previous studies had looked at temperature related mortality within a single country or region.

"This is the first study to get a global overview of mortality due to non-optimal temperature conditions between 2000 and 2019, the hottest period since the Pre-Industrial era," he said in a statement issued by Monash University.

On deaths attributed to abnormal cold and heat globally, the study found that more than half of such deaths occurred in Asia, particularly in East and South Asia.

Understanding the geographic patterns of temperature-related-mortality "is important for the international collaboration in developing policies and strategies in climate change mitigation and adaptation and health protection," Guo said.