Every year, Antarctic sea ice shrinks to its lowest levels towards the end of February, during the continent’s summer. The sea ice then builds back up over the winter. But, scientists have observed something different this year.
The sea ice has not returned to anywhere near expected levels and is at its lowest levels for this time of year since records began 45 years ago. The ice is around 1.6 million square kilometres (0.6 million square miles) below the previous winter record low set in 2022, according to data from the National Snow and Ice Data Center (NSIDC).0
In mid-July, Antarctica’s sea ice was 2.6 million square kilometres (1 million square miles) below the 1981 to 2010 average. That is an area nearly as large as Argentina or the combined areas of Texas, California, New Mexico, Arizona, Nevada, Utah, and Colorado
The phenomenon has been described by some scientists as off-the-charts exceptional – something that is so rare, the odds are that it only happens once in millions of years, as per CNN.
A glaciologist at the University of Colorado Boulder, Ted Scambos, said that speaking in these terms may not be that helpful.
“The game has changed,” he told CNN. “There’s no sense talking about the odds of it happening the way the system used to be, it’s clearly telling us that the system has changed.”
Scientists are now scrambling to figure out why.
As per CNN, the Antarctic is a remote, complex continent. Unlike the Arctic, where sea ice has been on a consistently downward trajectory as the climate crisis accelerates, sea ice in the Antarctic has swung from record highs to record lows in the last few decades, making it harder for scientists to understand how it is responding to global heating.
Scientists have since 2016 begun to observe a steep downward trend. While natural climate variability affects the sea ice, many scientists say climate change may be a major driver for the disappearing ice.
“The Antarctic system has always been highly variable,” Scambos said. “This [current] level of variation, though, is so extreme that something radical has changed in the past two years, but especially this year, relative to all previous years going back at least 45 years.”
Several factors feed into sea ice loss, Scambos said, including the strength of the westerly winds around Antarctica, which have been linked to the increase of planet-heating pollution.