According to a statement from the National Snow and Ice Data Center (NSIDC), the extent of sea ice in Antarctica has surpassed its record low last year and also set it earlier than last year.
On February 13, 2023, the extent of sea ice in Antarctica decreased to 1.91 million square kilometers. This set a new record low, falling below the previous record of 1.92 million square kilometers set on February 25, 2022. This year is only the second year that the extent of Antarctica has fallen below 2 million square kilometers, the statement said.
In previous years, the annual low occurred between February 18 and March 3, so further declines are expected this year, he said. With the melt season likely still several weeks away, the range is expected to continue to decline before reaching its annual low. Much of the Antarctic coast is ice-free, exposing the ice shelves that line the ice sheet to wave action and warmer conditions, the statement said.
NSIDC is an American information and reference center for the support of polar and cryospheric research. NSIDC is part of the University of Colorado Boulder Cooperative Institute for Research in Environmental Sciences (CIRES) and is affiliated with the National Oceanic and Atmospheric Administration (NOAA) National Centers for Environmental Information through a cooperative agreement.
According to the NSIDC statement, sea ice extent as of mid-December is well below last year’s melt season. A positive southern annular mode led to stronger than average westerly winds. Along with the strong Amundsen Sea surface, the weather conditions brought warm air to the region on both sides of the Antarctic Peninsula, the statement said.
This has largely cleared the ice sheet in the Amundsen and Bellingshausen Seas and reduced the extent of sea ice in the northwestern Weddell Sea, the NSIDC said. Sea ice is patchy and almost absent along a long stretch of Antarctica’s Pacific coast, the NSIDC said. Previous studies have linked low sea ice to waves generated by pressures on floating ice shelves that line the continent, leading to the breakup of weaker areas, the statement said.
The extent of Antarctic sea ice has been highly variable over the past few years. While 2022 and 2023 had record low minimum range, four of the five highest minimums have occurred since 2008, the NSIDC said. Overall, the trend in Antarctic minimum extent between 1979 and 2023 is nearly zero, the NSIDC said.
The current downward linear trend in Antarctica’s minimum extent from 1979 to 2023 is 2,400 square kilometers per year, or 0.9 percent per decade, which is not currently statistically significant, the NSIDC said. However, the sharp decline in sea ice extent since 2016 has prompted research into potential causes and whether Southern Hemisphere sea ice loss is developing a significant downward trend, the statement said.
