Arctic Sea Ice Reaches 2026 Annual Minimum Extent

On September 12, 2026, NASA and the National Snow and Ice Data Center (NSIDC) at the University of Colorado Boulder reported that Arctic sea ice had reached its annual minimum extent. Covering an estimated 1.78 million square miles (4.6 million square kilometers), this marked the lowest minimum in the satellite record, tying 2008, 2010, and 2025 for the 10th-lowest extent.

This 2026 minimum aligns with patterns observed in the satellite record; from 2007 to 2026, the past 20 years have produced the 20 lowest annual Arctic sea ice minimum extents since continuous satellite measurements began in late 1978. Arctic sea ice expands during the cold, dark autumn and winter, then retreats as temperatures rise in spring and summer, typically reaching its lowest in September.

Weather conditions can lead to significant variations in the amount of ice that melts from one summer to the next. Increased cloud cover in recent years, preventing solar radiation from further accelerating the melt, has contributed to relatively stable September sea ice extent. Senior research scientist Walt Meier from NSIDC noted that despite the plateau, the ice remains low compared to earlier periods in the record.

Meanwhile, Antarctic sea ice is nearing its annual maximum following a fluctuation in August. Over a six-day period, Antarctic sea ice declined by approximately 116,000 square miles (300,000 square kilometers), but resumed its seasonal growth. Meier explained that this decline was likely due to weather conditions that compressed thin, mobile ice near its outer edge.

Antarctic sea ice varies more year to year than Arctic sea ice due to its lack of surrounding land and greater responsiveness to changing winds and weather conditions. However, the annual maximum for Antarctic sea ice has generally been lower in recent years, making it difficult to characterize this variation as a long-term trend.

Scientists have been tracking polar sea ice from space for nearly five decades, with NASA and NOAA using a series of satellite instruments since 1978. The current record continues with data from the Advanced Microwave Scanning Radiometer 2 (AMSR2), launched in 2012 aboard JAXA's GCOM-W satellite. Scientists will announce the 2026 Antarctic sea ice maximum once they confirm the end of the seasonal ice growth.