2026年北极海冰最大值创纪录新低：为何与2025年基本“打平”

NSIDC and NASA’s Earth Observatory, 27 March 2026

Arctic sea ice has spread to its greatest area or “maximum extent” for 2026, as occurs each year around the spring equinox (March 20-21), when the sun has returned to the entire Arctic Ocean and sea ice stop its winter growth and begins the melt season; reaching its small area or “minimum extent” in September-October before freezing and spreading again in winter.

This year’s maximum appears to have occurred on March 15, when extent reached 14.29 million square kilometers. This is the smallest maximum in the 48-year satellite record, falling about 20,000 square kilometers lower than 2025’s record-low level. The 2025 sea ice extent mostly ran lower than 2026; however a slight growth spurt occurred last year just before the 2025 maximum was reached a week later than that of 2026, around March 22, 2025; rising just slightly above the March 15, 2026 level (see figure below).

The margin of error for these satellite records however is 30,000 square kilometers, so this year’s 20,000 square kilometers lower maximum extent is within this margin, meaning that the National Snow and Ice Data Center (NSIDC) has declared 2025 and 2026 statistically “tied” for this troubling record-low: yet another sign of the growing negative impact of greenhouse gas emissions on the Arctic cryosphere.

As reported earlier, along with the record-low overall extent, researchers documented notably thinner Arctic sea ice this year, especially in the Barents Sea northeast of Greenland. NSIDC also observed that this year’s winter record low is 1.36 million square kilometers below the 1981-2010 average, an area of sea ice loss equivalent to twice the size of Texas.

NSIDC Interactive Arctic Sea Ice Graph

Description: 2026 Arctic sea ice extent in light blue; 2025 extent in dark green; and 2012 (lowest summer minimum Arctic sea ice extent) in red dashes. Grey highlights indicate median extent for 1981-2010.

NSIDC Summary | News Coverage | NSIDC Interactive Arctic Sea Ice Graph