A once in every 2,000 years event is happening in the Antarctic

The loss of sea ice - which is 10 times the size of the UK - in the Antarctic sea is a one-in-2,000-year event according to research.

Researchers from the British Antarctic Survey used the CMIP6 climate dataset to examine the extensive sea ice loss occurring in the Antarctic. With the risk of levels reaching record lows being greatly increased by climate change.

In 2023, the Antarctic sea ice shrank to historically low levels, it was particularly confusing, as sea ice had been steadily increasing up until 2015.

Using the dataset, the team analysed data from 18 different climate models to understand the probability of such a sharp reduction in sea ice.

Lead author Rachel Diamond explained that whilst 2023's extremely low sea ice was made more likely by climate change, it was still considered very rare according to the models.

She says: “This is the first time this large set of climate models has been used to find out how unlikely 2023’s low sea ice actually was. We only have forty-five years of satellite measurements of sea ice, which makes it extremely difficult to evaluate changes in sea ice extent. This is where climate models come into their own.

According to the models, the record-breaking minimum sea ice extent would be a one-in-a-2000-year event without climate change. This tells us that the event was very extreme – anything less than one-in-100 is considered exceptionally unlikely.”

The researchers also used the models to examine how long it would take for the sea ice to recover. They found that even after twenty years not all of the sea ice around Antarctica returns.

Louise Sime, a co-author of the study, says: “The impacts of Antarctic sea ice staying low for over twenty years would be profound, including on local and global weather and on unique Southern Ocean ecosystems – including whales and penguins.”

Research like this is crucial in understanding how likely rapid sea-ice losses are, and if sea ice is likely to stay low over the coming decades.

This article was originally published on 4 June, 2023.

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