In the southern hemisphere summer of 2022, the amount of sea ice dropped to 1.92m sq km on 25 February – an all-time low based on satellite observations that started in 1979.
But by 12 February this year, the 2022 record had already been broken. The ice kept melting, reaching a new record low of 1.79m sq km on 25 February and beating the previous record by 136,000 sq km – an area double the size of Tasmania.
In the southern hemisphere’s spring, strong winds over western Antarctica buffeted the ice. At the same time, Hobbs says large areas in the west of the continent had barely recovered from the previous year’s losses.
“Because sea ice is so reflective, it’s hard to melt from sunlight. But if you get open water behind it, that can melt the ice from underneath,” says Hobbs.
Hobbs and other scientists said the new record – the third time it’s been broken in six years – has started a scramble for answers among polar scientists.
The fate of Antarctica – especially the ice on land – is important because the continent holds enough ice to raise sea levels by many metres if it was to melt.
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While melting sea ice does not directly raise sea levels because it is already floating on water, several scientists told the Guardian of knock-on effects that can.
Sea ice helps to buffer the effect of storms on ice attached to the coast. If it starts to disappear for longer, the increased wave action can weaken those floating ice shelves that themselves stabilise the massive ice sheets and glaciers behind them on the land.
One major area of concern is a marked loss of ice around the Amundsen and Bellinghausen seas on the continent’s west.
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