More than 150,000 people have died every year worldwide due to heat waves since 1990, according to new research.
Europe had the highest population-adjusted mortality rate, according to the first global mapping of heat wave-triggered deaths.
The global surface temperature has increased by 1.14 degrees Celcius from 2013 to 2022, say scientists, and is expected to rise by another 0.41C to 3.41C by 2081 to 2100.
They warned that, with the increasing impacts of climate change, heat waves are increasing not only in frequency but also in severity and magnitude.
Previous studies have quantified the effect of individual heat waves on excess deaths in local areas, but have not compared statistics around the globe over such a prolonged period.
The new research, published in the journal PLOS Medicine , looked at statistics on daily deaths and temperature from 750 locations across 43 countries.
The team estimated excess heat wave deaths around the world spanning 1990 to 2019 and mapped the variance in these deaths across continents.
The research was led by Professor Yuming Guo, of Monash University , Australia, and involved colleagues at the London School of Hygiene and Tropical Medicine and Shandong University , China.
The research team explained that heat waves raise the risk of people dying due to "overwhelming thermal stress" on the human body. They also cause heat exhaustion, heat cramps, and heatstroke.
Guo said heat stress can also aggravate pre-existing chronic health conditions, leading to premature death, psychiatric disorders and other negative impacts on well-being.
The team found that, during the warm seasons from 1990 to 2019, heatwaves accounted for 153,078 deaths per year, a total of 236 deaths per 10 million residents - or one percent of global deaths.
While Asia had the highest number of estimated deaths, Europe had the highest population-adjusted rate, at 655 deaths per 10 million residents.
A "substantial" burden of estimated deaths was seen in southern and eastern Europe as well as the area between Northern Africa, the Arabian Peninsula and Southern Asia.
At the national level, Greece, Malta, and Italy had the highest excess death ratios.
Overall, the largest estimated rates of heat wave deaths were seen in areas with dry climates and lower-middle incomes.
Understanding the regional disparity of heatwave-related mortality is key to planning local adaptation and risk management towards climate change, according to the research team.
Guo said: “Heatwaves are associated with substantial mortality burden that varies spatiotemporally over the globe in the past 30 years.
“These findings indicate the potential benefit of government actions to enhance health sector adaptation and resilience, accounting for inequalities across communities.”
He added: “In the context of climate change, it is crucial to address the unequal impacts of heatwaves on human health.
"This necessitates a comprehensive approach that not only tackles immediate health risks during heatwaves but also implements long-term strategies to minimize vulnerability and inequality.
"The strategies include climate change mitigation policy, heat action plans, urban planning and green structure, social support programs, healthcare and public health services, education awareness, and community engagement and participation.”
By Stephen Beech via SWNS