That’s why researchers are concerned – dagsavisen

In the Southern Hemisphere, winter turns into spring. At this time of year, the extent of sea ice in the sea surrounding Antarctica is at its peak.

But this year, sea ice surface area reached a record low, satellite data show. The US National Snow and Ice Data Center (NSIDC), which is behind the measurements, says the record has been broken by a wide margin. Since measurements began in 1979, no less sea ice has been seen at this time of year.

“It’s not just a record year, it’s a very record year,” says senior researcher Walt Meyer of NSIDC in a statement to the press.

Check turning points

– There is speculation about whether these are natural fluctuations or climate change. I would prefer to have natural fluctuations, Sven Oosterhuis, a senior researcher at the Nourse Research Institute, tells Dagsavisen.

“But we see that there are changes in weather systems around Antarctica, so we see the impact of that as well,” he adds.

Oosterhus has been researching Antarctica for decades, and has visited it himself several times. In recent years, he has worked on an international project investigating the possibility of reaching tipping points that cause Antarctica’s ice to melt rapidly.

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Less protection against heating

Although the reason for the decrease in sea ice extent is not clear, it is clear what the consequences are.

In August, a new study was published showing that several thousand emperor penguin chicks died last year when ice melted in nesting areas before the chicks were old enough to survive in the sea. NRK writes.

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Sea ice in Antarctica

• The US National Snow and Ice Data Center (NSIDC) has been measuring the extent of sea ice around Antarctica since 1979.
• On September 10, the maximum sea ice extent for the year was measured at 16.96 million square kilometers.
• The level was 1.03 million square kilometers lower than the previously recorded low.
• Sea ice is at its greatest levels in the winter months, so the measurement taken on September 10 will likely still be the peak level for the year.

Source: NTB/NSIDC

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The lack of sea ice can have consequences for many animal species and the ecosystem as a whole both above and below the ice. According to researchers At the Meteorological Institute.

With the Southern Hemisphere now moving towards summer, declining sea ice will also mean that the sea around Antarctica is less protected from global warming. While white ice reflects sunlight, dark seas absorb more of the sun’s heat.

-If there is less sea ice, the ocean absorbs more heat. As a result, it becomes less stamina, Oosterhuis explains.

The ocean plays an important role in absorption, but warm oceans absorb less than cold oceans.

Changes in weather systems

Oosterhuis explains that the coldest water in the world forms beneath Antarctica’s ice shelves. From there, it floats and settles at the bottom of all the world’s oceans.

An ice shelf is a relatively permanent sheet of ice that extends over the sea as a continuation of the inland ice that lies on land. Outside the barriers lies sea ice, which fluctuates with the seasons and is now at a record low.

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Sea ice protects ice shelves, which in turn protect inland ice. As ocean sea ice decreases, bream become more vulnerable.

Oosterhuis’ research team concluded that changes in weather systems around Antarctica were already having consequences.

– Last year, we looked at the consequences of the heaviest water coming from Antarctica, which lies at the bottom of all the world’s oceans. He says that the amount of this water was less, and this is related to changes in weather systems.

-The biggest worry

Oosterhuis says Antarctica’s large ice shelves are of greatest concern to scientists.

– What is happening now with the ice shelves in the Amundsen Sea is that warm water is coming under them and melting them. Oosterhuis says this has been happening for several years.

The barriers cover a total area of ​​1.5 million square kilometers, an area the size of Greenland. The two largest are Ross, which is the size of France, and Ron-Felchner, which is slightly smaller.

– These two large islands are believed to be safe, because a lot of sea ice forms in front of them, so the cold, heavy water also sinks to the bottom and protects the floating ice. He explains that the hot water outside is unable to penetrate.

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Although there will be less sea ice next summer, it will be a long time before the consequences of global warming become apparent.

-The big brakes still feel safe and stable. Recent research results show that collapse will not happen in today’s climate, but if the climate continues to warm, it will happen, Oosterhuis says.

It could be bad

– If the big ice caps start melting, it will be bad, says Oosterhuis.

He adds that the prevailing models that researchers are working with show that major ice melting will not occur for three to five hundred years from now.

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As it stands, the UN Climate Panel says we should expect sea levels to rise by 1 meter within this century. It doesn’t seem like much, but there’s also a strong storm, Oosterhuis says.

He points to the Great North Sea Flood of 1953 as an example, when a combination of spring tides and powerful storms led to major flooding and loss of life along the coasts of the Netherlands, England, Belgium, France and Denmark.

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