The extent of Arctic sea ice reached historic lows during the winters of 2025 and 2026, according to a study by the University of Southampton and the National Oceanography Center, published in PNAS.
New satellite measurements reveal that, after an apparent stagnation in the downward trend, the loss of ice intensified again, confirming its direct relationship with climate change.
Key research data
- Between February and March 2025, ice extent fell by 5.8% compared to the previous year, the largest year-on-year reduction since 1978.
- In 2026 there was a slight recovery, but it remained the second lowest coverage in the historical record.
- The analysis confirms that short-term recoveries only hide the long-term trend: ice loss continues to be active.
Function of sea ice
Arctic ice plays an essential role as a climate regulator:
- It acts as a barrier between the ocean and the cold atmosphere.
- It limits the exchange of heat and moisture.
- It influences storm formation and atmospheric circulation patterns in the northern hemisphere.
Its decrease facilitates ocean warming and alters weather dynamics at lower latitudes, with potential impacts on distant regions.
Models and simulations
Researchers compared satellite images with climate models adjusted to the level of warming recorded in the Arctic in 2025 (+2.8 °C).
- The sharp decline in ice was uncommon but possible according to the simulations.
- The models suggest that, under current conditions, winter ice will fluctuate around low levels in the coming years, without a rapid recovery.
Professor Simon Josey explained: “Winter sea ice is more likely to fluctuate around a lower level than to recover quickly to conditions of the early 2020s”.
Global impacts
The loss of Arctic ice has consequences that transcend the region:
- Hemispheric climate: changes in atmospheric pressure and air circulation.
- Storms: alteration in their formation and trajectory.
- Marine ecosystems: reduction of habitat for ice-dependent species.
- Human communities: impact on indigenous populations and economic activities linked to the Arctic.
The reestablishment of the downward trend in Arctic ice extent confirms that the loss continues and intensifies in an increasingly warm climate. As lead author Duo Chan noted, “short-term recoveries can temporarily hide the long-term trend”.
The evidence reinforces the need for more studies to understand how internal variability and external forcing interact in the Arctic system and how its changes can have planetary-scale repercussions.
