"The impossible is now possible." As France swelters under a "historic" heatwave and parts of Europe experience temperatures unprecedented for the month of June, scientists from World Weather Attribution (WWA) published, on Friday 26 June, an initial report on this event, "the most severe the region has ever experienced". Their conclusion is unequivocal: “The maximum temperatures observed both day and night during this heatwave would have been virtually impossible at this time of year barely fifty years ago,” in 1976, they warn.
Drawing on an analysis of the three hottest days and three hottest nights recorded across several European countries, the WWA asserts that the current heatwave owes its severity solely to climate change caused by human activity, ruling out in particular the influence of El Niño – the ocean current that develops in the Pacific and leads to a rise in global average temperatures. “Scientists like me are starting to sound like a broken record,” laments Friederike Otto, professor of climate science at Imperial College London and co-author of the report.
"Year after year, we make the same statements in response to extreme heatwaves that are reaching ever-higher levels. Yes, this is indeed climate change; yes, we are responsible for it; no, it is not El Niño; yes, we have the solutions; but no, we are not implementing them quickly enough," explains Friederike Otto, professor of climate science at Imperial College London, in a press release.
"Continued emissions from fossil fuels [oil, gas and coal] are directly responsible for the disruption people are experiencing this week in their homes, schools and workplaces," adds his colleague Theodore Keeping. A researcher specialising in extreme weather events and forest fires, he points out that “it is scientifically established that climate change exacerbates heatwaves”. Yes, but to what extent?
According to the report, “the stifling night-time temperatures that are keeping many people awake this week are about 100 times more likely to occur today than they were just twenty-three years ago, during the infamous 2003 European heatwave”, the scientists write. As for the likelihood of experiencing daytime heat peaks similar to those currently being observed, it is “around 10 times higher” than it was back then.
In 1976, the year in which some of the previous European heat records were set, “the temperatures of 2026 would have been virtually impossible to reach in June, and highly unlikely at any time of year”, continues the study, carried out by researchers from Sweden, Denmark, the US, the Netherlands, Ireland and the UK. Thus, a heatwave occurring under similar conditions at the same time of year would have resulted in temperatures “around 3.5 °C cooler during the day” and “around 2.4 °C cooler at night”, according to their calculations. In 2003, daytime temperatures would have been “around 2°C cooler”, whilst night-time temperatures would have been “around 1.3°C lower”.
For the WWA, this heatwave demonstrates that, given the current level of global warming – estimated at +1.4°C compared with pre-industrial levels – “extreme heat is already pushing our societies to the limits of their capacity to cope”. They are therefore calling for a faster phase-out of fossil fuels.
"As climate change continues, a summer like the one we are currently experiencing will by no means be exceptional. Unless, of course, we reduce our greenhouse gas emissions," said Theodore Keeping, an expert on extreme weather events at Imperial College London, at a press conference.
As well as the heat records, the WWA has also drawn attention to the ‘wet-bulb globe temperature’ records observed in recent days in several countries. According to their estimates, 45 per cent of the 854 towns analysed across 30 European countries have recorded a WBGT (Wet Bulb Globe Temperature) index that is unprecedented for the end of June. This indicator, which measures heat stress and the body’s ability to cool itself through the evaporation of sweat, has broken records in the Czech Republic, Luxembourg and Lithuania, as well as in Germany, the Netherlands and Poland. The report emphasises that these conditions make this heatwave “dangerous”.
Since the 19th century, the Earth’s average temperature has risen by 1.3°C. Scientists have established beyond doubt that this rise is due to human activities involving the use of fossil fuels (coal, oil and gas). This warming, unprecedented in its speed, threatens the future of our societies and biodiversity. But solutions – renewable energy, energy efficiency and reduced meat consumption – do exist. Find out our answers to your questions about the climate crisis.
An article written by Marie-Adélaïde Scigacz (France Télévisions), initially published on 26 June 2026, 06:31 (CEST)