A plateau, not a recovery
Arctic sea ice reached its smallest extent of the year on September 12, according to NASA and the National Snow and Ice Data Center. The ice covered 4.60 million square kilometres, or 1.78 million square miles, at that point. That figure ties 2008, 2010 and 2025 for the tenth-lowest minimum in the satellite record.
The long-term trend remains downward. Every summer from 2007 through 2026 now ranks among the 20 lowest minimum extents since satellites began continuous monitoring in 1978. The all-time low came in September 2012.
“We have plateaued, but we are still low relative to the earlier part of the record,” said Walt Meier, a senior research scientist at NSIDC. The decline steepened in the 2000s and set off a run of record and near-record years.
Clouds slow the melt
One reason the numbers have steadied is cloud cover. Over the past decade, more clouds in summer have blocked some solar radiation from reaching the surface and accelerating the melt, according to Linette Boisvert, a sea ice scientist at NASA's Goddard Space Flight Center.
Sea ice grows through the dark, cold autumn and winter and retreats as temperatures rise in spring and summer, usually reaching its lowest extent in September. Weather conditions can cause large differences from one summer to the next, which is why a single year rarely breaks a record.
The Antarctic sits near the other extreme
At the opposite pole, Antarctic sea ice most likely reached its yearly maximum on September 14 at 17.59 million square kilometres, or 6.79 million square miles. If that date holds, it would be the third-lowest maximum in the satellite record. Antarctic extent tracked near record-low levels for most of the growth season.
Scientists have maintained a continuous polar ice record for nearly five decades, starting with NASA's Nimbus-7 satellite in October 1978 and continuing through later instruments. Each September since 2007 has ranked among the 20 lowest Arctic minima, a run that now stretches to 20 straight years.