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Antarctica has less sea ice than it has at any time in the past 40 years.

Research ship Polarstern in ice-free Antarctica in January 2023

According to satellite observations, the Antarctic is experiencing less sea ice than it has at any time in the past 40 years. Currently, only 2.20 million square kilometers of the Southern Ocean are covered in ice. The research team from the Alfred Wegener Institute and the University of Bremen are analyzing the situation for the Sea Ice Portal. In January 2023, the sea ice extent had already set a new record low with a monthly mean of 3.22 million square kilometers. The expedition team on board RV Polarstern has reported virtually ice-free conditions in the Bellingshausen Sea.

The sea ice decline in the Antarctic has been rapid over the past six years, compared to the previous 35 years, when the ice cover hardly changed. The melting has progressed, especially in the Bellingshausen and Amundsen Seas in the West Antarctic, which is now virtually ice-free. It is still unclear whether this is the beginning of a rapid end to summer sea ice in the Antarctic or the beginning of a new phase characterized by low but still stable sea ice in the summer.

Antarctic sea ice reaches its maximum extent in September or October and its minimum extent in February. In some regions, the sea ice completely melts in the summer. The Sea Ice Portal team’s analysis shows that the ice was at its lowest extent in January 2023 than at any time of year since the beginning of record-keeping in 1979.

The intense melting could be due to high air temperatures and the Southern Annular Mode being in a positive phase, intensifying the westerly winds and causes them to contract toward the Antarctic. This intensifies the upwelling of circumpolar deep water on the continental shelf and promotes sea-ice retreat and the melting of ice shelves, which is an essential aspect for future global sea-level rise.

Historical records show the tremendous changes that have taken place in the Antarctic. One hundred twenty-five years ago, the Belgian research vessel Belgica was trapped in the pack ice for more than a year in the same region where the Polarstern can now operate in completely ice-free waters. These changes offer a unique chronicle of the ice conditions at the dawn of the industrial age and serve as a benchmark for comparison with today’s climate change.

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Research ship Polarstern in ice-free Antarctica in January 2023 via University of Bremen with usage type - News Release Media

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Research ship Polarstern in ice-free Antarctica in January 2023 via University of Bremen with usage type - News Release Media

 

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