Record-Low Arctic Winter Sea Ice in 2025 and 2026 Signals Continued Decline

PNAS, 20 July 2026

After several years in the early 2020s when Arctic winter sea ice appeared to stabilize, satellite observations showed exceptionally low winter sea ice extent during 2025 and 2026, indicating that this pause was temporary. The study analyzed more than four decades of satellite observations, focusing on two key phases of the Arctic sea ice cycle: the winter ice growth period (November-January) and the seasonal peak in ice extent (February-March). Between 2024 and 2025, winter sea ice extent fell by 720,000 km² during the growth phase – the largest year-to-year decline in the satellite record. An additional 140,000 km² was lost in 2026, reducing winter ice extent to a record low of 11.3 million km². Although peak winter sea ice recovered slightly in 2026, it remained the second-lowest on record. The updated observations show that the apparent slowdown in Arctic winter sea ice decline during the early 2020s no longer holds when the record-low winters of 2025 and 2026 are included. Climate models also indicate that while the sharp decline in 2025 was unusual, it is consistent with continued Arctic warming and is likely to be followed by persistently low winter sea ice. These findings reinforce that Arctic winter sea ice continues to decline despite short-term natural variability. and highlight the importance of monitoring changes in sea ice across seasons to provide important information on the Arctic’s capacity to recover from a warming climate.

Papper | Summary by the University of Southampton