For many years, climate researchers have given the same answer to the question of which regions on our planet are being changed the most by global warming: the polar regions are changing more radically than other areas, especially the surface beyond the Arctic Circle, which is characterized by ice and water .

Joachim Müller-Jung

Editor in the feuilleton, responsible for the "Nature and Science" department.

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This observation has now been confirmed in a study by Finnish scientists led by Mika Rantanen from the Finnish National Weather Service in Helsinki - and at the same time it has been significantly corrected: since the 1970s, the Arctic has not only warmed two to three times faster than the global average, which has long since become exorbitant ice melts, but even four times as strong.

The researchers report on their analysis in a recent study in the journal Communications Earth & Environment.

A research group based in the Norwegian city of Tromsø, which recently evaluated the temperature data for the Arctic Council, came up with an increase in the average Arctic surface temperature between 1971 and 2019 by 3.1 degrees in mid-2021.

That would mean a threefold acceleration in global warming.

This was already well above earlier results and also well above the global climate models used by the Intergovernmental Panel on Climate Change (IPCC).

The reasons for this are evidently, among other things, that the algorithms of the computer models have been imprecisely capturing the physical changes associated with global change since the phenomenon of Arctic amplification was first described in the 1980s.

Even the current climate models do not appear to correctly depict all influencing factors, which is why the fourfold acceleration has not yet been simulated.

The exact reason for this remains unclear for the time being.

According to the scientists, it is possible that the effect of greenhouse gases is fundamentally underestimated in the models due to the complexity of the interactions, or that the heat flows between land, sea and ice surfaces, especially in the Arctic, are not yet recorded.

Almost half of the ice surface is lost

In fact, the dynamics of sea ice melt has surprised scientists: since the late 1970s, 40 to 50 percent of the ice surface has been lost, which leads to above-average temperatures in the Arctic Ocean, especially in the autumn and winter months.

However, the Finnish researchers themselves also attribute their higher estimate to methodological deviations.

With their definition of what is to be regarded as the Arctic, they deviate from older studies.

They defined the Arctic as the entire area that is within the Arctic Circle.

They also did not calculate the rate of warming from the early 1970s as they used to, but from 1979 – the year since more reliable satellite images became available.

The study thus provides further evidence that the assessments of climate researchers and the IPCC with regard to the speed of global warming tend to be too cautious - and the crisis is therefore likely to escalate faster than expected in many places.