Arctic sea ice shrank to 4.60 million square kilometres (1.78 million square miles) on September 12, 2026, its lowest extent of the year and about 1.62 million square kilometres below the 1981-2010 average minimum. The National Snow and Ice Data Center at the University of Colorado Boulder, which published its analysis on September 23, says that shortfall is equivalent to the loss of an area the size of Alaska.
Ranked against the satellite record, the 2026 minimum ties for tenth lowest. That is a middling place with a grim footnote.
What 4.60 million square kilometres measures
Sea ice extent is the total area of ocean where ice covers at least 15 percent of the surface, as defined on the Sea Ice Index page run by NOAA and NSIDC, built from passive microwave satellite data going back to 1979. The satellites cannot see the small region around the North Pole itself, and the index assumes it is covered. The figure is preliminary, NSIDC cautions, because late-season storms could still move ice around before a fuller analysis is released in early October.
The NSIDC analysis puts the 2026 minimum 1.21 million square kilometres above the record low of 3.39 million set in 2012. It shares its rank with 2008, 2010 and 2025 in a satellite record of nearly 48 years.
The word “normal” needs pinning down. NSIDC measures the gap against the average minimum extent for 1981 through 2010, a fixed three-decade baseline. Adding the reported shortfall of 1.62 million square kilometres (625,000 square miles) to this year’s 4.60 million implies an average minimum of about 6.22 million square kilometres for that period. The Alaska comparison is NSIDC’s own, and it converts a number too large to picture into a shape most readers can place on a map.
Twenty lowest minimums in twenty years
The most striking statistic sits in the fine print. NSIDC reports that the last 20 years, 2007 through 2026, are the 20 lowest sea ice extents in the satellite record, so every minimum since 2007 is below every minimum before it. NSIDC puts the long-term loss at about 73,200 square kilometres a year, an 11.8 percent decline per decade against the 1981-2010 baseline.
Yet the minimums themselves have stopped falling in a statistically significant way. NSIDC says there has been no significant decrease in the September minimum over the past two decades, a plateau at a low level. Walt Meier, an NSIDC senior research scientist, described this year’s minimum, as reported by Petroleum News, as “yet another low extent in a changed Arctic.”
NASA’s release quotes Meier saying the ice has plateaued but remains low compared with the earlier part of the record, and it carries a possible reason for the pause from Linette Boisvert of NASA’s Goddard Space Flight Center: cloud cover has increased over the past decade, and the clouds block some sunlight and slow further melt.
A tie with last year’s number
The tie with 2025 is literal. NSIDC’s 2025 analysis recorded the same 4.60 million square kilometres, reached on September 10, 2025, and the same gap of 1.62 million square kilometres below the 1981-2010 average. In that analysis the tenth-lowest spot was shared with 2008 and 2010, so 2026 has joined an existing cluster instead of pushing the ranking in either direction.
NSIDC’s earlier report described the long-term decline as 12.1 percent per decade since 1979 and made the same point about the absent trend in minimums, calling the cause a question actively debated among Arctic scientists. The 2026 report puts the decline at 11.8 percent per decade, a small change in the stated rate between the two reports. The pattern matters for how this year’s tie should be read. NASA’s account stresses that ice grows through the dark winter months and retreats in spring and summer, and that weather variations shape melt rates year to year. Minimums that land in the same place in consecutive years are what a weather-buffeted system sitting on a lower floor would produce, and one tied rank is too little to show either a new plateau or a resumed decline.
The Antarctic comparison
The southern hemisphere is behaving differently. NSIDC says Antarctic sea ice likely peaked at 17.59 million square kilometres on September 14, the third lowest maximum on record. NASA adds that Antarctic ice dropped by 116,000 square miles over six days in August before resuming growth, which scientists attribute to weather-driven compaction of ice and note varies more than the Arctic because it lacks surrounding land.
The size of the final Arctic number is still moving. NSIDC’s early-October analysis will show whether storms shifted the 4.60 million square kilometres, and whether 2026 keeps its tie for tenth or slips a place in either direction.
This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.
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