The new year started with the familiar refrain of climate extremes, as scientists with the National Snow and Ice Data Center reported Jan. 3 that the sea ice around Antarctica dropped to its lowest extent on record for early January.
“The current low sea ice extent … is extreme, and frankly we are working to understand it,” said Antarctica expert Ted Scambos, a senior research scientist with the Earth Science and Observation Center at the University of Colorado at Boulder.
Scambos said the sea ice extent is about 270,000 square miles less than the previous low, set in 2018. That’s an area just a bit bigger than Texas, and the measurements reflect a persistent, strong trend toward lower-than-average Antarctic sea ice extent that started in 2016 and shows no signs of letting up, he added.
The Antarctic region has warmed more slowly than much of the rest of the planet, but recent research shows that the Southern Ocean, encircling Antarctica and extending northward to 60 degrees south latitude, stored an estimated 45 to 62 percent of the global increase in ocean heat between 2005 and 2017 despite comprising only 6.25 percent of the planet’s total ocean surface area.
Scambos said the poleward contraction of a belt of westerly winds around Antarctica, combined with the effects of other persistent regional winds, created “a pattern that favors slowly nudging the ice northward into warmer air and ocean conditions.”