The record-breaking heatwave engulfing Western Europe would have been "virtually impossible" without human-caused climate change, which has made this week's soaring night-time temperatures 100 times more likely than they would have been just two decades ago, scientists said on Friday.
"Over the region studied, this heatwave is the most severe ever recorded," the World Weather Attribution group of climate scientists said in an analysis. Britain recorded a record-high temperature for June on Thursday, amid the deadly heatwave that has killed dozens, disrupted power supplies and shut schools and cultural landmarks.
Global warming has worsened Europe's heatwaves in just a few decades, the WWA analysis found. A similar heatwave in June 1976 would have been around 3.5 degrees Celsius cooler than this one, WWA said.
Of more than 800 European cities analysed, 45% have recorded, or are forecast to record, their highest heat stress levels for late June, the research found. Heat stress occurs when the body cannot cool itself through sweating.
Greenhouse gas emissions drive warming
Scientists have confirmed through years of studies that human-caused global warming is making heatwaves both more likely and intense. Greenhouse gas emissions, mostly from burning coal, oil and gas, have increased the planet's average temperature to around 1.4 C above pre-industrial times in the 19th century, according to the World Meteorological Organization.
"We are not doing enough to slow the rate of global warming at the moment. And so as that rate of warming continues ... we should expect to see record temperatures being exceeded more and more frequently," said Clair Barnes, a research associate in extreme weather at Imperial College London, who co-authored the WWA analysis.
Europe is the world's fastest-warming continent. The WWA analysis said the health impacts of this heatwave are just beginning to emerge, and pointed to a scientific study which found more than 60,000 people died from heat-related causes amid a series of heatwaves in the summer of 2022.
Health risks in heatwaves are exacerbated by extreme night-time temperatures, which hamper the body's ability to recover from daytime stress. In parts of France, overnight temperatures have stayed above 20 C for more than a week — a temperature threshold known as a "tropical night" — with some nights recording minimum temperatures of nearly 30 C.
The El Niño weather pattern, which has formed in the tropical Pacific and tends to increase global temperatures, did not contribute to Europe's severe heat, WWA said.