The sea ice that covers the Arctic Ocean is shrinking from year to year, under the effect of climate change. And for the first time it could disappear completely, at least for a day, from 2027. This is the conclusion of a study published Tuesday, December 3 in the journal Nature Communicationsby researchers from the University of Gothenburg (Sweden) and the University of Colorado (United States).
More specifically, scientists define the Arctic Ocean as « free of ice » when it only extends over less than a million km² in total. Each year, the sea ice grows during the winter then melts during the summer, reaching its minimum surface area in September. And this minimum surface area is shrinking like a skin: from 12 % per decade on average, according to NASA satellite observations. In recent years, the minimum has been around 4 million km².
In 2023, the same researchers already estimated that the Arctic could experience its first full ice-free month as early as 2035. In their new numerical simulations, the authors estimate that the first ice-free day would have the highest probability of occurring by 7 at 20 years old.
But in the most extreme scenarios — 9 simulations out of 366 — the event could occur as early as 2027. The most worrying thing is that this early occurrence of the event could be triggered whatever the scenario of our future carbon emissions.
In other words, the probability of this happening so quickly is low but it depends above all on the internal variability of the climate, on unpredictable variations. Several consecutive extremely warm years in the region, as well as the occurrence of storms, could in certain conditions be enough to overcome the ice.
The first day without ice will be mainly symbolic, note the researchers. He will not signal the triggering of a climate tipping point on his own, but emphasizes that we are getting closer to this risk. The only way to weaken these probabilities is to drastically reduce our greenhouse gas emissions, the authors point out.
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