- In the winter of 2023, there was 2.2 million square kilometers less ice than normal
- Without climate change, these low levels would be a one-in-2,000-year event
The record-breaking low levels of sea ice around Antarctica in 2023 could be caused by climate change, experts say.
Last year there was 2.2 million square kilometers less ice than normal during the winter around Antarctica – equivalent to about 10 times the area of Britain.
To find out why this happened, researchers from the British Antarctic Survey (BAS) analyzed data from 18 different climate models.
They found that historically low sea ice levels in Antarctica were a one-in-2,000-year event without climate change, but four times more likely under its effects.
Rachel Diamond, lead author of the paper, said: ‘This is the first time this large suite of climate models has been used to find out how unlikely the 2023 low sea ice actually was.
Record-breaking low sea ice levels around Antarctica in 2023 could be caused by climate change, experts say
Last year there was 2.2 million square kilometers less ice than normal during winter around Antarctica – equivalent to about 10 times the size of Britain
‘We only have 45 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-2,000-year event without climate change.
“This tells us that the event was very extreme; anything less than one in a hundred is considered exceptionally unlikely.”
The vast expanse of Antarctica’s sea ice regulates Earth’s temperature, as its white surface reflects the sun’s heat back into the atmosphere and cools the water below.
Without it, the planet would be a much warmer place.
For the study, the team used the latest climate dataset called CMIP6 to investigate whether warming played a role in Antarctica’s sea levels.
For the study, the team used the latest climate dataset called CMIP6 to investigate whether warming played a role in Antarctica’s sea levels.
Antarctica’s vast expanse of sea ice regulates Earth’s temperature, as its white surface reflects the sun’s heat back into the atmosphere and cools the water below
Caroline Holmes, co-author of the study, said: ‘Strong climate change – meaning the temperature changes we are already seeing, and the changes we expect if emissions continue to rise rapidly – makes it four times more likely in the models that we are seeing such a large reduction in the extent of sea ice.
“This suggests that the extreme low of 2023 was made more likely by climate change.”
The BAS scientists also looked at how well sea ice is likely to recover and found that it would remain low even after 20 years.
This would impact penguins, whales and other animals that rely on the ice for habitat, the researchers said.
Louise Sime, co-author of the study, said: ‘The consequences of Antarctic sea ice remaining low for more than 20 years would be significant, including on local and global weather and on unique ecosystems in the Southern Ocean, including whales and penguins.’
Sea ice formation around Antarctica acts as a driver for ocean currents and influences weather patterns.
It also protects the exposed edges of the ice shelves from waves, limiting Antarctica’s contribution to sea level rise.
Until 2015, winter sea ice in Antarctica had been increasing since satellite surveys began in 1978.
The findings have been published in the journal Geophysical Research Letters.