Antarctica had less winter ice in 2024 than in any year except 2023

Antarctic ice, at its annual peak this year, covered the second lowest area on record. It was just shy of last year’s record high, continuing what scientists fear is a trend caused by climate change.

The ice covered 17.16 million square kilometers (6.63 million square miles) of Antarctica at its maximum extent on Sept. 19, according to preliminary figures released Thursday by the National Snow and Ice Data Center at the University of Colorado at Boulder. Last year’s low of 16.96 million square kilometers broke the previous record set in 1986.

Calling the downward movement over the past two years “dramatic,” Ted Scambos, a senior researcher at the university’s Cooperative Institute for Environmental Science Research, said in a statement that it “signifies more than ever the effects of a record-warm ocean. ” on the polar region.

In Antarctica, sea ice usually covers the largest extent of the ocean at some point in September. After that, a slow melt begins during the Southern Hemisphere summer, with the clearest water usually seen in early March. The same process occurs in the Arctic, but the maximum and minimum times are reversed.

Scientists have come to expect long-term declines in Arctic sea ice. But for a long time, Antarctica appeared to be more resilient, leading researchers to wonder how much longer it might continue, said Cecilia Bitz, a professor of atmospheric and climate science at the University of Washington.

“Now Antarctica seems to be catching up,” she said.

A year or two of lower ice maximum numbers could be explained by natural variability, but there have been enough weak years in the past decade to suggest a pattern, Bitz said: “I think we can say that Antarctica is now in decline “.

The National Snow and Ice Data Center released its latest estimates of summer ice cover for the opposite side of the planet last month. Sea ice covered only 4.28 million square kilometers of the Arctic Ocean at its minimum extent. This is the seventh lowest ice minimum on record. The 18 lowest Arctic ice extents have all occurred in the past 18 years.

The rate of warming in the Arctic continues to surprise scientists. “The models are not keeping up,” Bitz said.

The Antarctic ice sheets are so huge that the impact on sea level rise could be significant if they melt. Arctic warming also has major planetary repercussions, including the loss of reflective ice that helps shield Earth from solar radiation and the thawing of permafrost that releases greenhouse gases.

Reducing carbon pollution to limit global warming would slow the loss of polar ice, although further loss is inevitable even if the world decarbonizes rapidly. Some scientists are studying other measures to preserve the ice, such as pumping water onto the ice to thicken it, covering the ice with reflective geotextiles, and cloud seeding to reduce the amount of sunlight reaching the planet’s surface.

Photo: Sea ice floats as seen from NASA’s Operation IceBridge research aircraft, which monitors ice loss in Antarctica, on November 4, 2017. Photo credit: Mario Tama/Getty Images North America

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