Scientists have reported that the area of the Antarctic Ocean covered by ice has shrunk to a record low, thereby exposing the thicker ice shelves buttressing Antarctica’s ground ice sheet to waves and warmer temperatures.
According to scientists at he National Snow and Ice Data Center in the United States, Antarctica’s sea ice fell to 1.91 million square kilometres this week, making it the lowest extent since records began in 1979 and it followed the previous all-time low that was set last year when the area of ice floating on the Antarctic Ocean fell below two million square kilometres for the first time.
“With a couple more weeks likely left in the melt season, the extent is expected to drop further before reaching its annual minimum,” the NSIDC said in a statement.
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Although melting sea ice has no discernible impact on sea levels because the ice is already in ocean water, the sea ice rings Antarctica’s massive ice shelves, and the extensions of the freshwater glaciers threaten catastrophic sea level rise over centuries if they continue melting as global temperatures rise.
The NSIDC said “much of the Antarctic coast” has water that is now without ice, “exposing the ice shelves that fringe the ice sheet to wave action and warmer conditions”.
The continent has not experienced the rapid melting of the past four decades that plague the ice sheets of Greenland and the Arctic due to global warming as the Antarctic cycle undergoes significant annual variations during its summers of thawing and winters of freezing.
However, the high melt rate since 2016 raises concerns that a significant downward trend may be taking hold and one of the great danger it poses is that it helps accelerate global warming.
When white sea ice – which bounces up to 90 per cent 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.
Last week, Europe’s Copernicus climate monitor (C3s) said that the January ice extent was already at a record low.
Globally, last year was the fifth or sixth warmest on record despite the cooling influence of a natural La Nina weather pattern.
Story was adapted from CNA
