The Arctic is warming up much faster than expected, study reveals!

L’Arctic has warmed almost four times faster than the rest of the world in the past 40 years: these conclusions of a new study, published in the journal Communications Earth & Environment of the group Nature, raise fears of an underestimation of the climate models of the poles, of which reheating has a major influence on sea level rise. The study significantly reassesses the rate of warming of the region around the North Pole upwards.

In 2019, the United Nations climate panel of experts (IPCC) had estimated that the Arctic was warming more than double the world average », as a result of a process specific to the region. This phenomenon, called “Arctic amplification”, occurs when the pack ice and snow, which naturally reflect the heat from Sunmelt in the sea water which absorbs more solar radiation and warms up.

Although scientists have long agreed on the observation of an accelerated warming of the Arctic, their estimates of the phenomenon differ however according to the period they choose to study or the definition, more or less extensive, of the geographical area. of the arctic.

A warming two or four times faster?

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, nearly four times faster than the rest of the planet.

Because of greenhouse gas generated by human activities, mainly by fossil fuels, the planet has already gained nearly 1.2°C since the pre-industrial era. ” 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 “, explains to AFP Antti Lipponen, member of the Finnish Institute of meteorology and co-author of the study.

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 that of Novaya Zemlya in Russia has warmed by 1.25°C per decade, about seven times faster than the rest of the world.

A difference due to the obsolescence of previous models

The team found that the most advanced climate models projected Arctic warming about a third lower than their own data show. This discrepancy, according to them, could be explained by the obsolescence of previous models of the arctic climate, in constant improvement.

” The next step might be to throw a eye on these models, to see why they do not predict what we see in observations and what impact this has on future climate projections said Antti Lipponen.

The intense warming of the Arctic, in addition to a serious impact on the inhabitants and the wildlife local, which depends on the continuity of sea ice for hunting, will also have global repercussions. ” the climate change is man-made and as the Arctic warms, its glaciers will melt, which will have a impact global sea levelworries Antti Lipponen. Something is happening in the Arctic and it will affect us all “.

Sea level rise

The melting of the ice cap is the main driver of sea level rise, ahead of the melting of glaciers and the expansion of the ocean as a result of warming water. The melting of the pack ice (the ice on the oceans) does not raise sea level.

According to the IPCC, the sea level has 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 the century.

The ice cap of Greenland, which could approach the ” tipping point of the melt according to recent studies, contains a quantity of ice-cold water capable of raising the level of the oceans of the Earth up to six meters.

The Arctic is warming four times faster than the rest of the planet

Until now, it was estimated that the Arctic was warming two to three times faster than the rest of the planet. But a new study has just changed that: it actually heats up four times faster.

Article of Lea Fournassonpublished on July 8, 2022

Since 1970, Arctic Amplification (AA), the relationship between Arctic climate change and those in the rest of the world, continues to increase. And it continues today: while the amplification factor was estimated between 2 and 3 until today, a new study published in the journal Geophysical Research Letters shows that it actually reaches 4. This means that the Arctic is warming four times faster than the rest of the planet! “People usually average all models and assume that the whole is more reliable than any single model. We show that the average does not work in this case”, said Petr Chylek, first author of the study and climatologist at Los Alamos National Laboratory.

Two key moments, in 1986 and 1999

The researchers also showed that the evolution of AA was marked by two key stages, in 1986 and 1999. Abandoned stages by most of climate models. Although the study formally identifies the origin of the first, for the second it is more complicated. “We attributed the first stage to the increase in concentrations of carbon dioxide and other pollutants in theatmospherebecause several models do it correctlyexplained P. Chylek, but we believe that the second step is due to climate variability because none of the models can reproduce the second step. »

Everything would have been done through feedback loops: because of warming, less sea ice forms, which modifies thealbedo sea ​​ice and tends to warm the Arctic even more. The same goes for water vapour, which is more present as the Earth warms up, and which is a powerful greenhouse gas and therefore tends to warm up the region and the planet even more. But in the future, this trend is likely to be reversed, but not for a good reason: if all the arctic sea ice is meltingand in the worst case this would happen before 2050, then there is no longer the ice-albedo feedback.