Temperature records are being broken across the continent now amid a heat wave unusually early in the season, according to CNN.

At the heart of the crisis is a heat dome, a stubborn high-pressure system that acts like a lid on a pot, trapping hot air and forcing it downward. High pressure pushes air toward the ground, and the more it sinks, the hotter it gets, with nowhere to escape. It can linger for days or even weeks and is a weather phenomenon made more likely and more intense by human-caused climate change.

"While we do occasionally have warm spells in May, what we're seeing now is unprecedented," said Stephen Dixon, a spokesperson for an U.K.- based weather forcast agency Met Office.

"Climate change is increasing the chances of breaking May temperature records", Dixon said. "What was around a 1-in-100 year event is now around a 1-in-33 year event."

The Earth is some 1.4°C warmer today compared to 1850-1900, when Europe industrialized.

But that continent has heated up by around 2.4°C, according to the European Union's Copernicus Climate Change Service.

"Almost all of this heat is driven by the human-induced greenhouse effect from fossil fuel emissions, with the actual distribution of this excess heat determined by (several) factors," Dr Ben Clarke, researcher in extreme weather and climate change at the U.K.’s Imperial College London, told AFP.

The heat dome, a ridge of high pressure sitting over the Iberian Peninsula and Western Europe, brings hot, sinking air,which, as it descends, dries out and heats up further, eroding cloud cover and allowing the sun to bake the ground below.

Acting like a force field in the atmosphere, the heat dome also pushes the jet stream, and any unsettled weather, further north.

The current heat dome ranks in the top 0.13 percent of all recorded high-pressure heat domes.

Broader shifts in atmospheric circulation have also made summer heatwaves across Europe more frequent and severe. High-pressure systems, which tend to bring calm conditions and elevated temperatures, have grown more prevalent over the continent.

"If you look over the last 20, 30 years, there has been a prevalence, especially in summer, of those sorts of anticyclonic conditions that are making heatwaves more likely," Dr Buontempo said.

A man cools off under a fountain in Paris on May 26. Photo by AFP

Geography also plays a significant role.

"Europe is connected to the Arctic, which is warming much faster than the rest of the planet," Clarke said.

The Arctic is now 3.2°C above pre-industrial levels, according to Copernicus.

Tighter air quality regulations have cut aerosol emissions across Europe since the 1980s, Singaporean news outlet The Straits Times has noted.

While that has been a public health success, it has had an unintended warming side effect, since fine airborne particles normally cool the atmosphere by reflecting sunlight and brightening clouds.

"While a reduction in air pollution is hugely important for respiratory health, it also increases the solar radiation at the surface, as many types of particulate matter deflect sunlight," Clarke said.

According to CNN, more than 62,000 people died from heat-related causes in Europe during the planet's hottest year on record in 2024.

The emerging El Niño, a natural climate cycle associated with above-average global temperatures, could push 2026 and 2027 even higher.

Scientists caution that far worse heat lies ahead: while this year is on track to be among the hottest ever recorded, it may still turn out to be one of the coolest years most people alive today will ever see.