The study raises fears of an underestimation of the climate models of the poles, whose warming has a significant influence on the rise in sea levels.
The Arctic has warmed nearly four times faster than the rest of the world over the past 40 years.
This is according to new work published in the journal
Communications Earth & Environment
of the Nature group.
In 2019, the United Nations Panel of Climate Experts (IPCC) estimated that the Arctic was warming "more than twice the global average", as a result of a specific process in the region.
The rate of warming of the region around the North Pole has therefore been reassessed upwards.
Plus 0.75°C per decade
The phenomenon, called "Arctic amplification", occurs when sea ice and snow, which naturally reflect the sun's heat, melt into seawater which absorbs more solar radiation and heats up.
Although scientists have long agreed on the observation of an accelerated warming of the Arctic, their estimates nevertheless diverge according to the period they choose to study or the definition, more or less extensive, of the geographical area of the Arctic. 'Arctic.
In the new study, the researchers, based in Norway and Finland, analyzed four sets of temperature data collected across the Arctic Circle by satellites since 1979. They concluded that the Arctic has warmed in average of 0.75°C per decade, almost four times faster than the rest of the planet.
"The scientific literature considers that the Arctic is warming about twice as fast as the rest of the planet, so I was surprised that our conclusion was much higher than the usual figure," says Antti Lipponen, member of the Finnish Institute of Meteorology.
Differences with the most advanced climate models
However, the study found large local variations in the rate of warming within the Arctic Circle.
For example, the Eurasian sector of the Arctic Ocean, near the Norwegian archipelago of Svalbard and the Russian one of Novaya Zemlya, has warmed by 1.25°C per decade, about seven times faster than the rest. of the world.
In addition, the team found that the most advanced climate models predicted Arctic warming about a third less than their own data show.
This discrepancy, according to them, could be explained by the obsolescence of previous models of the Arctic climate, which are constantly being improved.
"The next step might be to take a look at these models, see why they don't predict what we see in observations and what impact that has on future climate projections," said Antti Lipponen.
Sea level rise
The intense warming of the Arctic, in addition to a serious impact on the inhabitants and on the local fauna, which depends on the continuity of the sea ice to hunt, will also have global repercussions.
"Climate change is man-made and as the Arctic warms, its glaciers will melt, which will have a global impact on sea levels," said the scientist.
According to the IPCC, the sea level has risen by 20 cm since 1900. However, the rate of this rise has almost tripled since 1990 and, depending on the scenarios, the oceans could gain another 40 to 85 cm by the end of the century.
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