The Arctic is warming faster than expected

Warming in the North Pole will exceed all estimates. An alarming finding linked to the phenomenon of arctic amplification.

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

The study, published in the journal Communication Land & Environment by the Nature group, significantly reevaluates the rate of warming of the region around the North Pole. In 2019, the United Nations Intergovernmental Panel on Climate Change (IPCC) estimated that the Arctic was warming “more than double the world average», as a result of a process specific to the region. This phenomenon, calledarctic reinforcementoccurs when sea ice and snow, which naturally reflect the sun’s heat, melt into seawater, which 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 vary according to 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 year. 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 increased by almost 1.2°C since the pre-industrial era. “The scientific literature believes 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, 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 Arctic Ocean, near the Norwegian archipelago of Svalbard and the Russian one of Novaya Zemlya, is warming by 1.25 C° per year. decade, about seven times faster than the rest of the world.

Melting of the ice sheet

The team found that the most advanced climate models predicted Arctic warming about a third less than their own data showed. According to them, this discrepancy 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. 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 consequences. “Climate change is man-made, and as the Arctic warms, its glaciers will melt, affecting global sea levels” recalled Antii Lipponen. “Something is happening in the Arctic and it will affect us all“, he worries.

The melting of the ice sheets is the main driving force behind sea level rise, ahead of the melting of glaciers and the expansion of the ocean due to the warming of the water. The melting of the pack ice (the ice on the oceans) does not raise sea levels According to the IPCC, sea levels have risen by 20 cm since 1900. However, the rate of this increase has almost tripled since 1990 and, depending on the scenarios, the oceans could gain another 40 to 85 cm by the end of century. Greenland’s ice sheet, which could approach “turning pointof the melt, according to recent studies, contains an amount of ice-cold water capable of raising the level of the Earth’s oceans by up to six meters.

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