Record-Low Polar Sea Ice Is a Warning Sign for the Whole Planet

Arctic sea ice reached its annual minimum at 4.60 million km² on 12 September. This tied with 2008, 2010 and 2025 as the 10th lowest minimum in the satellite record. This was 1.62 million km², or about 26% below the 1981–2010 average minimum, an area roughly equivalent to Alaska. 

Antarctic sea ice most likely reached its annual maximum at 17.59 million km² on 14 September, which would make it the third lowest maximum on record if confirmed. This is about 1.12 million km², or 6% below the 1981–2010 average maximum, an area roughly equivalent to South Africa. 

This graph shows Arctic sea ice extent on September 12, 2026, compared with daily sea ice levels from the previous four years and the record low year, 2012. The 1981–2010 median is shown in dark gray, with gray shading showing the typical range of sea ice extent during that period. Credit: National Snow and Ice Data Center (NSIDC).

September marks two different milestones. In the Arctic, it’s the summer minimum extent – the lowest point after the summer melt season. In Antarctica, it’s the winter maximum extent, when sea ice normally reaches its highest peak.