The heatwave scorching western Europe is the most severe and widespread ever recorded and could not have occurred without human-caused climate change, scientists have said, as the UK sweltered through its hottest ever June day.
Temperatures reached 36.4C (97.5F) in Somerset on Thursday, the highest June temperature on record in Britain, prompting the Met Office to extend its red heat-health alert by 24 hours to 11pm on Friday. Across the continent, schools closed, hospitals struggled, and rail and air journeys were cancelled as the mercury surged to near or above 40C even before peak summer.
“Scientists say Europe's worst ever heatwave is impossible without climate change, as UK hits record June temperature.”
The analysis, from the World Weather Attribution (WWA) consortium – which includes scientists from Imperial College London and the Red Cross Red Crescent Climate Centre – found that such extreme heat would have been “virtually impossible” just 50 years ago. Using peer-reviewed methods, researchers compared the current event to the infamous hot summers of 1976 and 2003.
“This event would not have been possible in June without climate change,” said lead author Theodore Keeping, an extreme weather researcher at Imperial College London. “The three-day average nighttime temperatures would not have been possible at any time of year without climate change, and the chance of the three-day maximum daily temperatures like this occurring at any time of the year has increased by over 500 times” since 1976.
By 1976, the planet had warmed by just 0.3C above preindustrial levels; in 2003, by 0.6C; and last year by 1.4C. The scientists calculated that a similar heatwave in June would have been about 3.5C cooler during the day in 1976 and about 2C cooler in 2003. Nighttime temperatures, which are particularly dangerous as they prevent the body from cooling down, were about 2.4C cooler in 1976 and 1.3C cooler in 2003.
The current sweltering nights are now about 100 times more likely than in 2003, when an estimated 70,000 people died from heat-related causes across Europe. While a statistical analysis of deaths from this week will take time, the scientists said the heatwave was “certain to exact a heavy toll”.
Almost half of Europe’s 850 largest cities are enduring their worst ever heat stress – a combination of temperature and humidity. Higher humidity makes sweating less effective at cooling the body, making heatwaves even more dangerous. At least 100 million people in Europe were expected to face temperatures above 35C on Thursday.
“This is the most severe and widespread heatwave to have ever affected this large a region of Europe,” said Keeping. “We found that in the last 50 years, during which time the planet has warmed by 1.1C, the chance of a heatwave like this has changed immensely. … But do we expect this to be a cool summer going forward? That’s absolutely the case.”
The scientists warned that without urgent climate action, future heat conditions would become even more extreme and the current summer could seem relatively cool in retrospect.