More than a third of summer heat-related fatalities are due to climate change, researchers said, warning of even higher death tolls as global temperatures climb.

Previous research on how climate change affects human health has mostly projected future risks from heatwaves, droughts, wild fires and other extreme events made worse by global warming.

How much worse depends on how quickly humanity curbs carbon emissions, which hit record levels in 2019 but dipped sharply during the pandemic.

But a new study by an international team of 70 experts is one of the first – and the largest – to look at health consequences that have already happened, the authors said.

The findings, published in Nature Climate Change, were stark: data from 732 locations in 43 countries spread across every inhabited continent revealed that, on average, 37 percent of all heat-related deaths can be attributed directly to global warming.

The researchers found that it is not the increase in average summer temperature – up 1.5C since 1991 in the locations examined – that boosted death rates, but heatwaves: how long they last, nightime temperatures, and humidity levels.

Even wealthy nations remain vulnerable: in 2003, a relentless heatwave in western Europe claimed 70,000 lives.

Source: France 24