Arctic sea ice melt season stopped lengthening around 2010

A NASA-led study of satellite data from 1979 to 2023 found the Arctic sea ice melt season is about 40 days longer than in 1979, but its average duration has barely changed since around 2010. The lengthening was driven mainly by later autumn freeze-up rather than earlier spring melting.

• Arctic melt season is about 40 days longer than in 1979
• Most lengthening occurred before 2010, then average duration leveled off
• Later autumn freeze-up, not earlier spring melt, drove the change
• Since 2010 cloud shifts cut sunlight reaching parts of the Arctic Ocean