The sea ice that encircles Antarctica has reached near-record low levels for the third year in a row, raising concerns that the ice has undergone a permanent “regime shift” driven by climate change – with alarming consequences for ice shelves, Antarctic ecosystems and the global climate. Researchers say it remains unclear whether such a shift has occurred, but we may see more evidence in a matter of months.
One source of uncertainty is the short satellite record of Antarctic sea ice cover, which extends back only to 1979. That limited view makes it difficult to know the degree to which the current fluctuation in sea ice is part of natural variability in the Antarctic or a response to climate change.at the British Antarctic Survey says the magnitude of the change in sea ice suggests it is a combination of both.