5 million deaths a year are caused by abnormal temperatures

More than 5 million extra deaths a year can be attributed to abnormal temperatures, according to researchers at Monash University. 

The international research team looked at mortality and temperature data from across the world from 2000 to 2019, a period when global temperatures rose by 0.26C per decade.

The study, which is the first to definitively link temperature change to annual increases in mortality, found that 9.43% of global deaths could be attributed to cold and hot temperatures. 

This equates to 74 excess deaths for every 100,000 people.

Importantly the researchers found that cold-related deaths decreased by 0.51% from 2000 to 2019, while heat-related death increased by 0.21%.

Professor Guo, from the Monash University School of Public Health and Preventive Medicine, said: ‘This data shows that climate change 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.’

The data also revealed geographic differences in 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.

More than half of deaths occurred in Asia, particularly in East and South Asia, whereas Europe had the highest excess death rates per 100,000 due to heat exposure.

The mortality data from this study is significantly higher than the second-largest study published in 2015, which was based on 74 million deaths across 13 countries/regions.

Professor Guo added: ‘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.

‘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.’

Professor Guo highlighted the importance of further research in order to understand the geographic patterns of temperature-related mortality in order to help develop policies and strategies in climate change mitigation and adaptation and health protection.

Photo by Jay Wennington