We have underestimated the rate at which the Arctic is melting

Arctic sea ice is melting faster than once assumed. Today’s climate models should not yet absorb the steep rise in temperatures that have occurred over the past 40 years. This, according to a new study by researchers at the University of Copenhagen and other institutions.

Temperatures in the Arctic Ocean between Canada, Russia and Europe are warming faster than climate models scientists have been able to predict.

Over the past 40 years, temperatures have risen every decade, and even more so across the Barents Sea and around the Svalbard archipelago of Norway, where they have increased by 1.5 degrees during the period.

This is the conclusion of a new study published in Natural Climate Change.

“Our analyzes of conditions in the Arctic Ocean prove that we have clearly underestimated the rate of temperature rises in the atmosphere near sea level, which ultimately caused ice to disappear faster than we had thought,” explains Jens Hesselbjerg Christensen, a professor at the Niels Bohr Institute (NBI) of the University of Copenhagen and one of the researchers of the study.

Together with his NBI colleagues and researchers from the Universities of Bergen and Oslo, the Danish Metrological Institute and the Australian National University, he compared current temperature changes in the Arctic with climate fluctuations we know from, for example, Greenland during the ice age between 120,000 – 11,000 years ago.

“The abrupt increase in temperature that is now being experienced in the Arctic has only been observed during the last ice age. At that time, analyzes of ice sheets showed that temperatures over the Greenland ice sheet increased several times, between 10 and 12. degrees, over a 40 to 100-year period, “explains Jens Hesselbjerg Christensen.

He emphasizes that the significance of the steep rise in temperature is still fully appreciated. And that an increased focus on the Arctic and reduced global warming, more generally, are must.

Climate models must take abrupt changes into account

Until now, climate models predicted that Arctic temperatures would increase slowly and stably. However, the researchers’ analysis shows that these changes are moving at a much faster pace than expected.

“We have looked at the climate models analyzed and assessed by the UN Climate Panel. Only the models based on the worst case, with the highest carbon dioxide emissions, come close to what our temperature measurements have shown in the last 40 years, from 1979 to today. , “says Jens Hesselbjerg Christensen.

In the future, there should be more focus on being able to simulate the impact of abrupt climate change on the Arctic. If we do this, we can create better models that can accurately predict temperature increases:

“Changes occur so rapidly during the summer months that ice probably disappears faster than most climate models have ever predicted. We must continue to monitor temperature changes closely and incorporate the correct climate processes into these models,” says Jens Hesselbjerg Christensen. He concludes:

“Thus, the successful implementation of the necessary reduction of greenhouse gas emissions to comply with the Paris Agreement is essential to ensure an ice-packed Arctic throughout the year.”