Antarctic sea ice likely shrunk to a record low last week, US researchers said on 27 February – its lowest extent in the 45 years of satellite record-keeping. The National Snow and Ice Data Center (NSIDC) at the University of Colorado Boulder said that Antarctica‘s sea ice fell to 691,000 square miles on 21 February. That exceeded the previous record low set in 2022 by 52,500 square miles.
NSIDC scientists stressed that the latest figure was preliminary, as further late-season melt was still possible. They said they would issue a final number on the extent of ice in early March. It added that the two-year consecutive downward trend “is not especially meaningful” because it’s such a short period of time. Since its records began in 1979, NSDIC has recorded a one percent per decade decline in Antarctic sea ice coverage.
Antarctica’s sea ice is precarious
Melting sea ice exposes the thicker ice shelves buttressing Antarctica’s ground ice sheet to waves and warmer temperatures. Melting sea ice itself has no discernible impact on sea levels because the ice is already in ocean water. However, the sea ice rings around Antarctica’s massive ice shelves. As the sea ice disappears, it exposes the shelves. It is the melting of these shelves that threatens catastrophic sea level rise over centuries if they continue melting as global temperatures rise.
Ted Scambos, a senior research scientist at the Cooperative Institute for Research in the Environmental Sciences (CIRES), said:
Antarctica’s response to climate change has been different from the Arctic’s.
The downward trend in sea ice may be a signal that global warming is finally affecting the floating ice around Antarctica, but it will take several more years to be confident of it.
And, as the Canary previously reported, changes in Antarctic sea ice coverage necessarily include the impacts of climate breakdown. Penn State geoscientist Richard Alley said:
We have changed the climate significantly, and everything happens within that changed climate
Antarctica isn’t as bad as the Arctic… yet
The Antarctic cycle undergoes significant annual variations during its summers of thawing and winters of freezing. However, the continent has not yet experienced the rapid melting of the past four decades that plagues the ice sheets of Greenland and the Arctic due to global warming. But a high melt rate since 2016 raises concerns that a significant downward trend may be taking hold.
The melting of the sea ice is problematic because it helps accelerate global warming. When white sea ice – which bounces up to 90% of the sun’s energy back into space – is replaced by dark, unfrozen sea, the water absorbs a similar percentage of the Sun’s heat instead.
Globally, 2022 was the fifth- or sixth-warmest year on record, despite the cooling influence of a natural La Niña weather pattern.
Featured image via Peter Prokosch/GRIDA
Additional reporting by Agence France-Presse
