On Wednesday, Pierre Masselot received a text from his daughter’s nursery – less than 50 miles from the weather station that was the first this week to break the UK June temperature record – asking parents to collect children early because the school buildings were getting unbearably hot.

Similar scenes were repeated across Europe this week as the continent swelters through its most severe and widespread heatwave on record – an oppressive force made hotter by carbon pollution and less bearable by repeated failures to prepare for it. France experienced its hottest day and night on record, while the UK and Switzerland both broke their heat records for a June day.

For Masselot, an environmental epidemiologist at the London School of Hygiene & Tropical Medicine, who has become one of Europe’s leading detectives tallying the hidden death toll from heatwaves, the past few days are reminiscent of the terrible summer heat that swept Europe in 2003. While he was too young then to fear for his health, he was old enough to grasp the horrors it held.

Then, the teenager from southern France was bouncing basketballs in the sun at summer camp as brutal August heat turned towns and cities across Europe into ovens. Hot days stressed bodies and warm nights ruined rest. Older people, particularly women and those who lived alone, made up the bulk of the 70,000 victims who died from that summer’s extreme heat.

Now, the exceptions of the past have become the norms of today – and the exceptions of today will soon be the norms of tomorrow. By the time Masselot’s toddler is 14, the same age he was in 2003, global heating will have blown well past the 1.5C (2.7F) target that world leaders promised to keep temperature rises to by the end of the century, and punishing extremes will have hit uncharted heights.

“Climate scientists have been saying for a long time we’ll have a lot more 2003s,” said Masselot, now 37. “Now it’s become painfully obvious this is the case.”

Yet despite repeated warnings and rising awareness, heatwaves still bring large parts of the continent to its knees. Several hospitals in England have declared critical incidents as a result of extreme heat, with cooling units breaking down and critical IT systems stalling, while schools, workplaces and railways have been thrown into chaos and wildfires have broken out. In France, where half of all homes have poor protection from high heat, more than 55 people have drowned while trying to cool down, four young children have died inside hot cars and two nuclear reactors have been forced to close for lack of cooling water.

Has Europe failed to learn from its past? The devastation of summer 2003 triggered the first serious attempts to deal with heat, as governments linked early warning systems to rapid response measures for when temperatures rose, such as limiting travel, closing schools and cancelling non-urgent appointments in hospitals. Research has found such adaptations have proved successful, with mortality rates now far less sensitive to shifts in temperature. If the 2003 heatwave were to strike today with the same strength, a study found in November, the projected death toll would be 75% lower.

But at the same time, heatwaves are growing hotter, longer and more common – and it is entirely unclear if efforts to adapt will keep up with the rising concentrations of planet-heating pollution in the atmosphere. This year, early warning systems kicked into action before the summer had even begun, as shock May heat swept north-west Europe and shattered the UK’s historical temperature record for May by a full 2C. Two weeks later, the Europe chief of the World Health Organization (WHO), Hans Kluge, stood in Berlin to announce the update of the WHO’s guidelines for heat health action plans, 18 years after they were first released. Just two weeks have passed since then, and Berlin is facing 40C heat.

“The tragedy is twofold,” Kluge said of the 200,000 lives the WHO estimates Europe has lost to heat in the past four years. “First, most of these deaths were entirely preventable; and second, this is just the tip of the iceberg, with millions more people being affected physically and mentally.”

Climate breakdown is heating Europe faster than any other continent – the result of local weather patterns and proximity to the rapidly melting Arctic – and the current heatwave is no exception to its effects. A rapid attribution study published on Friday by World Weather Attribution (WWA) found it would have been “virtually impossible” at this time of year just 50 years ago.

Particularly troubling for human health are the sweltering overnight temperatures reached this week, which the scientists found were about 100 times more likely than in 2003, while the daytime peaks have grown about 10 times more likely. They ruled out any influence from El Niño, the natural warming weather pattern that recently formed in the Pacific. It will peak in strength toward the end of the year and is likely to make 2027 the hottest on record globally.

For scientists who have long warned that heatwaves are getting worse as carbon pollution rises, the failure to follow expert advice has become tiring. “There’s a sad inevitability to all of this, with scientists like me trotting out the same quotes year after year,” said Friederike Otto, a climate scientist at Imperial College London and co-author of the WWA study, speaking before this week’s records had been broken. “Yes it’s climate change, yes it’s us, no it’s not El Niño. Simply put, we remain on a one-way trip towards a more dangerous future, and it’s time we hit the brakes.”

What can be done? Heat and health experts have called for more shading to keep heat out of homes, better ventilation to cool them down as they warm, and more green space in cities to counter the urban heat island effect. Hospitals need more support and citizens should check on neighbours who are old or vulnerable due to illness. Some experts are wary of mass adoption of air conditioning, which heightens the risk of blackouts and worsens the urban heat island effect, but still want it in care homes, hospitals, schools and public transport. The latest WHO guidance recommends nuanced adoption, arguing it is “not a sustainable societal solution” but “remains crucial” for those at increased risk of high temperatures.

The WHO’s position is one that has been loudly rejected by the US far right, which has turned European aversion to mass air conditioning into a meme of a poor and overregulated continent. In a post on X boosted by Elon Musk, the world’s richest man and owner of the platform, a US tech chief executive shared a screenshot of text generated by a chatbot that said “Europeans should just install air-conditioning” and “the American approach to summer was correct all along”. The post has been viewed 19.5m times.

Similar sentiments have been shared by European far-right parties that have fought efforts to expand clean energy or make homes more energy efficient. Just under a year ago, Marine Le Pen, the leader of the French far right, called for a “grand plan” for air conditioning in the same week her party tried to block new wind and solar projects. The latest bout of heat has caused the debate to erupt in France once again, several months before presidential elections.

Yet urgent calls to cut emissions continue to be brushed off as centrist governments across Europe weaken climate policy and roll back green rules in the name of competitiveness. The UN secretary general, António Guterres, who warned that London was “cooking” at the start of the week, repeated his longstanding pleas at London Climate Action Week on Tuesday to stop burning fossil fuels. The next day, the organisers of a related panel on extreme heat governance cancelled it because it was too hot. The day after, the US president, Donald Trump, advised the UK’s likely next prime minister, Andy Burnham, to “open up the North Sea” for oil and gas drilling, despite experts saying it is a mature basin with at least 90% of accessible fossil fuels already used.

For Masselot, whose typical summer as a child involved sitting inside with all the shutters closed – “basically you live in a cave from 10am to 6pm” – there has at least been some progress in awareness of heat and how best to cope with it. “People have learned lessons and now we know the consequences it can have,” he said. “But sometimes it feels as soon as the summer has ended, we forget about it.”