Temperatures at the north pole soared more than 20˚C above average on Sunday, crossing the threshold for ice to melt.
Temperatures north of Svalbard in Norway had already risen to 18˚C hotter than the 1991–2020 average on Saturday, according to models from weather agencies in Europe and the US, with actual temperatures close to ice’s melting point of 0˚C. By Sunday, the temperature anomaly had risen to more than 20˚C.
“This was a very extreme winter warming event,” said Mika Rantanen, a scientist at the Finnish Meteorological Institute. “Probably not the most extreme ever observed, but still at the upper edge of what can happen in the Arctic.
The findings were confirmed by an Arctic snow buoy, which logged absolute temperatures of 0.5˚C.
Climate scientists estimate global temperatures through the re-analysis of billions of weather measurements from satellites, ships, aircraft and weather stations. But in remote regions such as the central Arctic, where there are fewer direct observation sites, it was “difficult to estimate the exact temperature anomaly”, said Rantanen.
“All the models I have seen indicate a temperature anomaly over 20˚C,” he said. “I would say 20-30˚C is the order of magnitude.”
The Arctic has warmed nearly four times faster than the global average since 1979, and extreme heat has become hotter and more common.”
Temperatures rising above freezing are of particular concern because they melt ice, said Dirk Notz, a climate scientist at the University of Hamburg. “There is no negotiating with this fact, and no negotiating with the fact that the ice will disappear more and more as long as temperatures keep rising.”
A study Notz coauthored in 2023 found Arctic summer sea ice would be lost even with drastic cuts to planet-heating pollution.
“We expect the Arctic Ocean to lose its sea-ice cover in summer for the first time over the next two decades,” said Notz. “This will probably be the first landscape that disappears because of human activities.”