Antarctic sea ice reached its lowest maximum extent on record on September 10, and the ice sheet should be growing at a faster rate during the darkest and coldest months.On September 10, 2023, sea ice around Antarctica reached its lowest winter extent of 6.5 million square miles (16.96 million square kilometers), according to researchers at NASA and the National Snow and Ice Data Center (NSIDC).
That's 398,000 square miles (1.03 million square kilometers) below the all-time low set in 1986, a difference roughly the size of Texas and California combined. The average maximum area between 1981 and 2010 was 7.22 million square miles (18.71 million square kilometers).
Effects and causes
The map at the top of this page shows Antarctic sea ice extent on September 10, 2023. "This is a record low for Antarctic sea ice extent," said Walter Meier, a sea ice scientist at the National Antarctic and Arctic Ocean Research Center (NSIDC). "Almost the entire Antarctic continent is seeing low growth, not just one area."
Scientists are working to understand the reasons for weak Antarctic sea ice growth, which may include a combination of El Niño, wind patterns and warming ocean temperatures. New research suggests that ocean heat likely plays an important role in slowing cold-season ice growth and promoting warm-season melt.
Arctic sea ice could reach its annual minimum extent on September 19, 2023, making it the sixth lowest in satellite records, according to researchers at NASA and the National Snow and Ice Data Center (NSIDC). Meanwhile, Antarctic sea ice reached its lowest maximum extent on record on September 10, and the ice sheet should be growing at a faster rate during the darkest and coldest months. Image credit: NASA Goddard Space Flight Center/Scientific Visualization Studio
Trends and climate feedback
Antarctic sea ice extent has hit a record low so far in 2023, a continuation of the downward trend that began after Antarctic sea ice reached a record high in 2014. Before 2014, the sea ice around the Antarctic continent increased slightly by about 1% every decade.
Melting sea ice at the poles contributes to climate warming because of a cycle called "ice-ice bed feedback." Bright sea ice reflects most of the sun's energy back into space, while open ocean water absorbs 90% of the sun's energy. The larger the area of the ocean exposed to sunlight, the more heat it absorbs, which warms the water and further delays the growth of sea ice.
NASA Earth Observatory image by Lauren Dauphin using data from the National Snow and Ice Data Center.