Scientists are unsure if the relatively small area of Antarctic sea ice is part of natural fluctuations or signs of a "regime shift," according to an article published in New Scientist on March 11.
below is the start of the article, written by James Dinneen.
NEW SCIENTIST:
"There are growing fears of an alarming shift in Antarctic sea iceAntarctic sea ice cover remains far below average levels for the third year in a row, but researchers are uncertain whether this is a permanent shift driven by climate change or part of natural fluctuations."
"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.
"Antarctic sea ice has long defied expectations. Modellers projecting its decline were flummoxed when sea ice cover increased up to 2015, even as sea ice in the Arctic declined. Then, sea ice cover fell sharply below average the following year, reaching a record low early in 2017. That started to look like a trend as the ice set another record low in 2022, then another in early 2023.
"Researchers were shocked when the ice failed to recover during the Antarctic winter in the middle of last year, remaining so far below average that “our statistical models didn’t work anymore”, says Edward Doddridge at the University of Tasmania in Australia.
"In 2024, sea ice cover has again shrunk to a near record low, reaching a minimum extent of just 1.99 million square kilometres on 20 February – the second lowest figure on record, according to the National Snow and Ice Data Center in the US.
"Now, “all eyes are on winter sea ice”, says Doddridge. “If 2024 is like last year, there’s going to be a lot of evidence suggesting that Antarctic sea ice has changed, potentially irreversibly.
"”However, whether the persistently low sea ice represents a permanent shift driven by climate change remains unclear, says Catherine Walker at Woods Hole Oceanographic Institution in Massachusetts.
" “Is it a trend, or is it an elongated blip, or a regime shift?
""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.
"Caroline Holmes at the British Antarctic Survey says the magnitude of the change in sea ice suggests it is a combination of both."
