Lower sea ice extent means that ocean waves will pound the coast of the giant ice sheet, further reducing ice shelves around Antarctica.
The 2023 minimum is the lowest in 45 years of satellite record-keeping, according to preliminary findings from the National Snow and Ice Data Center (NSIDC) at the University of Colorado Boulder, published on Monday.
Antarctica reached its minimum extent for the year at 691,000 million square miles on 21 February, researchers said, beating the record low set in 2022 by 52,500 square miles.
NSIDC scientists noted that the figure is preliminary, and continued melting could make the final amount even lower. A full analysis will be released at the beginning of March.
“Antarctica’s response to climate change has been different from the Arctic’s,” said Ted Scambos, senior research scientist at the Cooperative Institute for Research in the Environmental Sciences, in an email.
“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.
The South Pole region has so far escaped the accelerated melting taking place on the ice sheets of Greenland and the Arctic.
But melting has increased in the past decade, and with less sea ice comes more danger for Antarctica’s large glaciers. Dark ocean water absorbs more of the sun’s heat, which would typically bounce off the white ice.
NSIDC senior research scientist and University of Manitoba professor Julienne Stroeve said: “The sea ice helps to buffer large floating ice shelves and major outlet glaciers such as Pine Island and Thwaites, and if these glaciers begin a more rapid runaway loss of land ice, it could trigger a dramatic increase in sea level rise rates before the end of this century.”
Last year was Earth’s fifth or sixth warmest year on record, according to numerous scientific agencies including Nasa and the European space agency.