L’Arctique se réchauffe plus vite que prévu

L'Arctique se réchauffe plus vite que prévu

Warming in the North Pole region would exceed all estimates. An alarming observation linked to the phenomenon of Arctic amplification.

The Arctic has warmed almost four times faster than the rest of the world in the last 40 years: these conclusions of a new study raise fears of an underestimation of climate models of the poles, whose warming has a great influence on the increase in the level from sea.

The study, published in the journal Earth and Environment Communications from the Nature group, significantly reassesses the rate of warming in the region around the North Pole. In 2019, the United Nations Climate Panel (IPCC) estimated that the Arctic was warming “more than twice the world average», as a result of a process specific to the region. This phenomenon, calledarctic amplificationIt occurs when sea ice and snow, which naturally reflect the sun’s heat, melt into seawater that absorbs more solar radiation and heats up.

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Although scientists have long agreed on the observation of an accelerated warming of the Arctic, their estimates of the phenomenon nevertheless differ depending on the period they choose to study or the definition, more or less extensive, of the geographic area of ​​the 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, the year satellite data first became available.

They concluded that the Arctic has warmed an average of 0.75°C per decade, almost four times faster than the rest of the planet. Due to greenhouse gases generated by human activities, mainly from fossil fuels, the planet has already gained almost 1.2°C since the pre-industrial era. “The scientific literature estimates 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.“Antti Lipponen, a member of the Finnish Institute of Meteorology and co-author of the study, explains to AFP. However, the study found large local variations in the rate of warming within the Arctic Circle. For example, the Eurasian sector of the Ocean Arctique, près de l’archipel norvégien de Svalbard et celui russe de Nouvelle-Zemble, s’est réchauffé de 1.25 C° par décennie, soit environ sept fois plus vite que subtracté of the world.

melting of the ice sheet

The team found that the most advanced climate models predicted about a third less Arctic warming 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.Antti Lipponen said. 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, affecting global sea levels.Antii Lipponen recalled. “Something is happening in the Arctic and it will affect us all“, He cares.

The melting of the ice sheet is the main driver of sea level rise, ahead of the melting of glaciers and the expansion of the ocean due to warming water. The melting of the sea ice (ice in the oceans) does not raise the sea level. According to the IPCC, sea levels have risen 20 cm since 1900. However, the rate of this rise has almost tripled since 1990 and, depending on the scenario, the oceans could gain another 40 to 85 cm by the end of the century. The Greenland ice sheet, which could approach the “inflection pointAccording to recent studies, it contains an amount of frozen water capable of raising the level of the Earth’s oceans by up to six meters.


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