On Wednesday, Pierre Masselot got a text from his daughter's nursery - less than 50 miles from the UK weather station that broke the June temperature record - asking parents to pick up kids early because the school was getting worryingly hot. This scene repeated across Europe as the continent swelters through its most severe and widespread heatwave on record, made hotter by carbon pollution and less bearable by repeated failures to prepare. France experienced its hottest day and night on record; the UK and Switzerland broke June records.
Masselot, an environmental epidemiologist at the London School of Hygiene & Tropical Medicine, recalls the 2003 heatwave that killed 70,000 people. Now 37, he notes that what was exceptional then is now normal - and today's exceptions will be tomorrow's norms. By the time his toddler turns 14, global heating will have blown past the 1.5°C target.
Despite decades of warnings, heatwaves still cripple Europe. Several English hospitals declared critical incidents as cooling units failed and IT systems stalled. In France, over 55 people drowned trying to cool down, four young children died in hot cars, and two nuclear reactors shut due to lack of cooling water. Half of French homes have poor heat protection.
The 2003 heatwave triggered early warning systems and rapid response measures, which have proven effective - a study found mortality would be 75% lower if 2003 struck today. But heatwaves are growing hotter, longer, and more common. This year, early warning systems kicked in before summer, after May heat shattered the UK's May record by 2°C. Two weeks later, WHO Europe chief Hans Kluge updated heat health guidelines; two weeks after that, Berlin faced 40°C.
“The tragedy is twofold,” Kluge said of the 200,000 heat-related deaths in Europe over the past four years. “Most were entirely preventable, and this is just the tip of the iceberg.”
Climate breakdown is heating Europe faster than any other continent. A rapid attribution study by World Weather Attribution found this heatwave would have been “virtually impossible” 50 years ago. Overnight temperatures are now about 100 times more likely than in 2003; daytime peaks about 10 times more likely. El Niño played no role.
“There's a sad inevitability to all of this,” said Friederike Otto, climate scientist at Imperial College London. “We remain on a one-way trip towards a more dangerous future, and it's time we hit the brakes.”
Experts call for shading, ventilation, green spaces, and more support for hospitals. They're wary of mass air conditioning, which risks blackouts and worsens urban heat island effects, but want it in care homes, hospitals, schools, and public transport. The WHO recommends nuanced adoption.
This position has been loudly rejected by the US far right. In a post boosted by Elon Musk, a US tech CEO shared a chatbot-generated text saying “Europeans should just install air-conditioning” and “the American approach to summer was correct all along.” The post got 19.5 million views. European far-right parties echo this, with Marine Le Pen calling for a “grand plan” for air conditioning while blocking renewable projects.
Meanwhile, centrist governments weaken climate policy in the name of competitiveness. UN secretary general António Guterres warned London was “cooking” and urged stopping fossil fuels. The next day, a panel on extreme heat governance was cancelled - because it was too hot. The day after, Donald Trump advised UK's likely next PM Andy Burnham to “open up the North Sea” for drilling, despite experts saying 90% of accessible fossil fuels are already used.
For Masselot, there's been progress in awareness. “People have learned lessons,” he said. “But sometimes it feels as soon as the summer has ended, we forget about it.”