The extreme heat that gripped Norway, Sweden and Finland in July was about 2 degrees Celsius hotter and made at least 10 times more likely by the human-caused climate crisis, scientists have found.
The analysis by the World Weather Attribution group also concluded that heatwaves of this scale in the region are now almost twice as likely as they were just seven years ago, with further increases expected unless emissions are rapidly cut.
By the end of the century, such events could occur every two to three years if global heating continues at its current pace.
Temperatures in parts of Norway and Sweden climbed to 33–35C, far above seasonal norms for Fennoscandia, straining health services and infrastructure.
A weather station in the Norwegian part of the Arctic Circle recorded temperatures above 30C on 13 days in July, while Finland has had three straight weeks with 30C heat, breaking a half a century old record.
The heatwave led to warnings from herders that their reindeer were on the verge of dying in the heat, with some sightings of the animal close to cities.
“This heatwave was relentless. Two weeks of temperatures above 30C in this region is unusual and of course, highly concerning,” Dr Clair Barnes, researcher at the Centre for Environmental Policy Imperial College London, said.
“Climate change is fundamentally reshaping the world we live in. Cold-climate countries like Norway, Sweden and Finland, are now experiencing unfamiliar levels of heat, as recently seen in strained health systems and sightings of reindeer seeking shade in urban areas.”
Hospitals in Sweden reported a surge in heat-related admissions, while reindeer herders in northern Norway and Finland warned of animals dying as grazing lands dried out. The heat also worsened wildfires in central Sweden and fuelled toxic algal blooms along the Baltic Sea coast.
In a world without climate crisis, similar two-week heatwaves would be extremely rare, the researchers said. But today, with 1.3C of global warming, these heatwaves have become at least ten times more likely.
“This event should be taken as another reminder that no country is safe from climate change,” Friederike Otto, co-founder of WWA and senior lecturer at the Grantham Institute, Imperial College London, said.
“In recent weeks, sweltering temperatures have hit the US, Japan, South Korea and triggered huge wildfires in France and Türkiye.”
Europe is the fastest-warming continent, heating at roughly twice the global average. Once again, heatwave has gripped large parts of the continent this summer.
The UK is now in its fourth heatwave of the summer, with temperatures reaching 34–35C in parts of England this week and prolonged hot, humid conditions adding to health risks.
Record-breaking heat across Europe began as early as April, with the most extreme temperatures from mid-June leading to an estimated 2,300 heat-related deaths across 12 major cities – around three times higher than would have occurred without human-driven warming, according to Imperial College London research.
The heat has also intensified wildfire conditions after the UK recorded its worst year for blazes on record, surpassing 29,000 hectares burned by April. Elsewhere in Europe, Spain and Portugal broke national June temperature records, exceeding 46C, with regional highs set in at least ten other countries.
The WWA scientists said that while adaptation measures such as early-warning systems and heat action plans can save lives, the scale of future heat risks in Fennoscandia and across Europe depends on rapid global action to cut greenhouse gas emissions.
Without this, events once considered rare could become regular summer occurrences, with mounting tolls on health, ecosystems and economies.
“Burning oil, gas, and coal is killing people today. Fossil fuels are supercharging extreme weather and polluting the air we breathe,” Dr Otto said. “To stop the climate from becoming more dangerous, we need to stop burning fossil fuels and shift to renewable energy.”
