It has mostly been shrinking since 2016. Between 1979 and 2014, Antarctic sea ice extent grew by about 1% per decade, with record winter highs in 2012 through 2014, but the trend reversed after 2015 and the ice has generally stayed below its historical average since then. In 2023 Antarctica recorded both its lowest summer minimum and its lowest winter maximum in the satellite record.
According to NASA and the National Snow and Ice Data Center, the 2026 winter maximum, reached around September 14, covered about 17.59 million square kilometers (6.79 million square miles), the third-lowest maximum on record. Scientists are still tracking whether the decline is a lasting shift or falls within natural year-to-year variability.
Image: Antarctic sea ice at its 2024 maximum extent. NASA Scientific Visualization Studio, public domain, via Wikimedia Commons.