Human-caused climate change is responsible for more than a third of the world’s heat deaths, scientists say.
The study from the University of Bern in Switzerland calculated the human cost of global warming and found the world’s heat deaths were being caused by rising temperatures and more extreme weather.
In addition, the scientists said heat deaths only accounted for a small amount of fatalities caused by climate change, with more people dying from other extreme weather such as storms, flooding and drought.
Dozens of researchers looked at heat deaths in 732 cities around the world between 1991 and 2018 – and found 37% were caused by higher temperatures from human-caused warming.
And the experts warned that heat death numbers will continue to grow with rising temperatures.
“These are deaths related to heat that actually can be prevented,” Ana Vicedo-Cabrera, an epidemiologist at the University of Bern, said.
“It is something we directly cause.”
The highest percentage of heat deaths were in South America, and Ms Vicedo-Cabrera pointed to southern Europe and southern Asia as other hot spots.
Sao Paulo in Brazil had the most heat-related deaths in the country – averaging 239 per year.
About 35% of heat deaths in the US can be blamed on climate change with over 1,100 deaths a year in 200 American cities, the research found.
New York topped the list in the US, with 141 deaths a year and Honolulu had the highest portion of heat deaths caused by climate change – 82%.
The researchers used decades of mortality data in the sampled cities to plot curves showing how each city’s death rate changes with temperature and how the heat death curves vary from city to city.
Some cities adapt to heat better than others because of air conditioning, cultural factors and environmental conditions, Ms Vicedo-Cabrera said.
Researchers made their findings after looking at temperatures and comparing them with 10 models simulating a world without climate change.
They were then able to work out the extra heat deaths the world is seeing as a result of human-caused global warming.
“People continue to ask for proof that climate change is already affecting our health. This attribution study directly answers that question using state-of-the-science epidemiological methods,” said Dr Jonathan Patz, director of the Global Health Institute at the University of Wisconsin.
Dr Patz, who was not part of the study, said it was one of the first to detail climate change-related heat deaths now, rather than in the future.
Every day at 6.30pm, Sky News broadcasts the first daily prime time news show dedicated to climate change.
Hosted by Anna Jones, The Daily Climate Show is following Sky News correspondents as they investigate how global warming is changing our landscape and how we all live our lives.
The show will also highlight solutions to the crisis and show how small changes can make a big difference.