Arctic sea ice hits 2026 annual minimum, tying 10th-lowest on record

Arctic sea ice reached its annual minimum on 12 September, shrinking to an estimated 1.78 million square miles (4.6 million square kilometres), according to NASA and the National Snow and Ice Data Center (NSIDC) at the University of Colorado Boulder.

The figure ties 2008, 2010 and 2025 for the 10th-lowest minimum in the continuous satellite record, which began in late 1978. The past 20 years, from 2007 through 2026, have produced the 20 lowest Arctic sea ice minimums ever observed.

Over the last decade, increased cloud cover has prevented solar radiation from further accelerating the melt, according to Linette Boisvert, a sea ice scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. That has contributed to relatively stable September sea ice extent in recent years.

“We’ve plateaued, but we’re still low relative to the earlier part of the record,” said Walt Meier, a senior research scientist at NSIDC.

At the opposite pole, Antarctic sea ice is approaching its annual maximum after declining by roughly 116,000 square miles (300,000 square kilometres) over a six-day period in August before resuming its seasonal growth. Meier said the decline appeared associated with weather conditions that pushed and compacted the thin, mobile ice near its outer edge.

“Those types of things happen all the time,” Meier said. “But the magnitude of it certainly is unusual.”

NASA and NSIDC will announce the 2026 Antarctic maximum after scientists confirm that seasonal ice growth has ended.