Heatwave deaths to rise steadily by 2080: Study

Deaths caused by severe heatwaves will increase dramatically by 2080, particularly in countries located near the equator such as India, if we fail to counter climate change, a global study has found.

The study, published in the journal PLOS Medicine, is the first to predict future heatwave-related deaths and aims to help decision makers in planning adaptation and mitigation strategies for climate change.

Researchers at Monash University in Australia developed a model to estimate the number of deaths related to heatwaves in 412 communities across 20 countries for the period of 2031 to 2080.

The study projected excess mortality in relation to heatwaves in the future under different scenarios characterised by levels of greenhouse gas emissions, preparedness and adaption strategies and population density across these regions.

"Future heatwaves in particular will be more frequent, more intense and will last much longer," said Yuming Guo, an associate professor at Monash University.

"If we cannot find a way to mitigate the climate change (reduce the heatwave days) and help people adapt to heatwaves, there will be a big increase of heatwave-related deaths in the future, particularly in the poor countries located around the equator," Guo said.

A key finding of the study shows that under the extreme scenario, there will be a 471 per cent increase in deaths caused by heatwaves in three Australian cities (Brisbane, Sydney and Melbourne) in comparison with the period 1971-2010.

The study comes as many countries around the world have been affected by severe heatwaves, leaving thousands dead and tens of thousands more suffering from heatstroke-related illnesses.

"The collective death toll across India, Greece, Japan and Canada continues to rise as the regions swelter through record temperatures, humidity, and wild-fires," researchers said.

Since the turn of the century, it is thought heatwaves have been responsible for tens of thousands of deaths, including regions of Europe and Russia, said Antonio Gasparrini, an associate professor at the London School of Hygiene & Tropical Medicine.

"Worryingly, research shows that is it highly likely that there will be an increase in their frequency and severity under a changing climate, however, evidence about the impacts on mortality at a global scale is limited," Gasparrini said.

"This research, the largest epidemiological study on the projected impacts of heatwaves under global warming, suggests it could dramatically increase heatwave-related mortality, especially in highly-populated tropical and sub-tropical countries," Gasparrini said.

"The good news is that if we mitigate greenhouse gas emissions under scenarios that comply with the Paris Agreement, then the projected impact will be much reduced," he said.