Dramatic slowdown in melting of Arctic sea ice surprises scientists | Sea ice

The merger of sea ice into the Arctic has slowed considerably over the past 20 years, scientists have reported, without a statistically significant decline in its extent since 2005.

The observation is surprising, according to the researchers, given that carbon emissions from the combustion of fossil fuels continued to increase and trap more and more heat during this period.

They said that the natural variations in ocean currents that limit the fusion of ice has probably balanced the continuous increase in global temperatures. However, they said that it was only a temporary stay and that the melting was very likely to start over the long -term rate at a given time in the next five to 10 years.

The results do not mean that the Arctic Sea Ice is bouncing. The sea ice area in September, when it reached its annual minimum, has reduced by half since 1979, when satellite measures started. The climate crisis remains “unequivocal”, said scientists, and the need for urgent action to avoid the worst impacts remains unchanged.

The natural variation causing the slowdown is probably the multi-decadal fluctuations in the currents of the Atlantic and Pacific oceans, which change the quantity of hot water flowing in the Arctic. The Arctic should always see conditions without ice later in the century, harm people and fauna in the region and stimulating global heating by exposing the dark ocean and absorbing heat.

Dr. Mark England, who directed the study at the University of Exeter, said: “It is surprising, when there is a current debate on the question of whether global warming accelerates, that we are talking about a slowdown.

“The good news is that there are 10 to 15 years ago, when the loss of sea ice accelerates, some people spoke of an arctic without ice before 2020. But now the [natural] The variability has moved to cancel the loss of sea ice far. It bought us a little more time, but it is a temporary reprieve – at the end, this is not good news. “”

Research, published in the journal Geophysical Research Letters, used two different data sets of Arctic Sea Ice levels from 1979 to the present day. Scientists analyzed the sea ice area for each month of the year and the slowdown was observed in all cases.

To see if such a slowdown could be the result of a natural variation, they have examined the results of thousands of climate models. “It is not an extremely rare event – more than a century, it should happen several times,” said England, now at the University of California in Irvine. In addition, all simulations have shown that loss of sea ice is accelerating again after slowing down.

Professor Julienne Stroeve, of the University College of London, said: “We know that climate archives, whether in global temperatures or on sea ice, can remain the same for several consecutive years due to the variability of the internal climate.”

Stroeve’s analysis of the long -term trend from 1979 to 2024 shows that around 2.5 square meters of September ice is lost for each ton of CO₂ issued.

Professor Andrew Shepherd, of the University of Northumbria, said: “We know that the Arctic Sea Ice Pack is also in thinning, and therefore even if the area did not reduce, the volume is still. Our data show that since 2010, the average thickness of October has dropped by 0.6 cm per year. ”

The speed of increasing the overall surface temperature has also slowed down in the past, before resuming a rapid increase. A major event by El Niño in 1998 was followed by about a decade of similar global temperatures, which was nicknamed “the break”. However, the planet has continued to accumulate heat everywhere and global temperatures have since increased quickly.

England has rejected any suggestion that the slowdown in sea ice suggested that climate change was not real. “Climate change is unequivocal real, focused on humans and continues to constitute serious threats. Fundamental science and urgency for climate action remain unchanged,” he said.

“It is good to explain to people that [the slowdown] This happens, otherwise they will hear it from someone who tries to use it in bad faith in order to undermine our very solid understanding of what is happening with climate change. »»