The brutal heatwave sweeping Europe has now claimed the lives of four toddlers in France and over 55 drownings across the country, as the scorching conditions prepare to move east and choke 150 million people under 35°C (95°F) temperatures. Scientists have declared this the most severe and widespread heatwave ever, leaving nearly half of Europe’s 850 largest cities grappling with unprecedented heat stress - because, surprise, burning fossil fuels has consequences.

In Marseille, an 18-month-old died after being found in a car in a state of hyperthermia; police suspect the father forgot him when he was supposed to be dropped off at daycare. Earlier, a three-year-old in a Paris suburb died after climbing into a car and activating the child lock, and two more children, aged two and four, were found dead in their family’s car in a residential car park. Because apparently we need a heatwave to remind us that cars turn into ovens.

France’s sports minister, Marina Ferrari, reported at least 55 drownings, up from 40 earlier in the week. “We fear the situation may worsen,” she said, which is about as reassuring as a wet paper towel.

In the UK, the Met Office broke the record for the hottest June day for the third day running, hitting 37.3°C in Santon Downham, Suffolk. “Temperatures are still rising,” they added, as if we needed reminding. A red alert for heat remained in place for London and south-east England for an unprecedented third day, while an amber alert covered most of central and eastern England. The UK Health Security Agency’s red heat-health alert extended until 11pm Friday, covering all of southern and central England - because even healthy people are at risk now.

More than 1,000 schools closed or partially shut, train passengers were urged to avoid non-essential travel, and firefighters tackled a wildfire in Derbyshire affecting 200 hectares. A hosepipe ban in Kent came into effect, and Britain’s energy operator raised the alarm over power supplies for air conditioning and fans. The London ambulance service responded to its highest number of life-threatening emergencies ever on Wednesday, and its chief operating officer expects demand to “grow day on day.”

In Paris, where temperatures hit a June record of 40.9°C on Wednesday, officials banned drinking takeaway alcohol in the street. The head of the Association of French Emergency Doctors reported 55 deaths in emergency care in Paris in 24 hours - compared to the usual three or four. “Fifty-five is enormous,” Patrick Pelloux said, understating the situation.

Organisers of Paris Pride postponed the event, likely until September, to avoid overwhelming emergency services. Pride in Lyon and the Solidays music festival were also called off.

While temperatures peak in France and Britain, the heat is expected to intensify in central and eastern Europe. Belgium cancelled a re-enactment of the Battle of Waterloo, the Netherlands cancelled the Defqon 1 techno festival, and Budapest Pride will go ahead despite a heat alert, asking vulnerable people to “support us from home.”

Parts of the Balkans braced for temperatures up to 39°C, Austria warned of buckling train tracks, and Germany hit a preliminary national record of 41.3°C near Saarbrücken, after the A2 motorway buckled. Meanwhile, Greece and Cyprus enjoyed early Etesian winds, with tourists ambling comfortably around Athens - because irony.

John Kennedy of the World Meteorological Organization noted that Europe has warmed by about 2°C since the 1976 heatwave. “Heatwaves like this are what we expect to see in a changing climate,” he said. “Extreme heat will occur more frequently, for longer duration and with greater intensity as global warming continues.” So, get used to it - or, you know, do something about it.