Those impacts could include increased storm frequency and ocean heat loss, according to a 2024 study. Earlier this year, a wide-ranging scientific review concluded that changes in Antarctica’s sea ice cover “affect the global distribution of atmospheric heat and moisture and atmospheric variability.” The “speed and persistence” of sea ice decline suggests that the ocean around Antarctica may be transitioning to a new state that is likely to impact not just Antarctic ecosystems but the entire global climate system, the research says.
Animation of the maximum extent of Antarctic sea ice, September 10, 2023, to its minimum, February 20, 2024.
Michael Meredith, an oceanographer with the British Antarctic Survey who led the BAS Polar Ocean for years, said the new research shows that dramatic sea ice loss in Antarctica since 2016 is already having an impact on the properties and circulation of deep sea water.
“The Southern Ocean is the critical nexus for all of the world’s oceans,” he said. “It is the main site where old water is recycled into new, so this could have global implications.”
The Southern Ocean also plays a “massive role” in reducing human carbon emissions, mitigating the rate of climate change where people live, he said. Anything that disrupts important ocean cycles requires our attention, he added.
Meredith said it was not yet clear whether the shift was permanent because it was based on a relatively short observational record. But he said global climate models that guide policy still struggle to accurately reflect recent sea ice losses, showing more research and monitoring is needed.
“Our climate models need to catch up,” he said. “But if low sea ice levels continue, these changes will spread further into the world’s oceans and the impacts will ripple through our climate and ecosystems.”
Similar research in recent years has found that deep circulation in the Southern Ocean has slowed, reducing the rate at which new water floods and cools the deepest areas. The new study makes it clear that the upper part is changing rapidly in response to changes in sea ice, he said. “This is important,” he added, “because the upper circulation can influence our climate within years to decades, not centuries.”
Bob Berwyn is an Austria-based reporter who has been covering climate science and international climate policy for more than a decade. He previously covered the environment, endangered species and public lands for several Colorado newspapers and also worked as an editor and editorial assistant at community newspapers in the Colorado Rockies.
This story originally appeared on Inside Climate News.
