• Arctic winter sea ice is back in rapid decline after a brief slowdown in melting, with exceptionally low sea ice observed in 2025 and 2026 winters in the Arctic.
• Between 2024 and 2025, Arctic sea ice extent during the winter peak phase fell by 5.8%, the largest year-to-year wintertime drop in the satellite record, indicating a significant decline in winter sea ice.
• Current levels of Arctic warming suggest that Arctic winter sea ice is more likely to fluctuate around a lower level over the next few years than quickly rebound to early 2020s conditions, according to climate change models.

Arctic winter sea ice is back in rapid decline after a brief slowdown in melting, scientists in the UK said on Monday.

Human-driven global warming has been causing winter sea ice loss over the last decades, although scientific findings indicated that the rate had weakened in the region in the early 2020s.

But an analysis led by the University of Southampton, alongside the National Oceanography Centre, of recent satellite observations found exceptionally low sea ice in 2025 and 2026 winters in the Arctic.

When added to long-term trends, the team said it suggests the area's winter sea ice loss has returned to a state of significant decline.

Duo Chan, lead author of the paper from the University of Southampton's School of Ocean and Earth Science, said: "This sharp drop changes the way we interpret recent Arctic winter sea ice change.

"What looked like a pause in the early 2020s now appears to have been a temporary slowdown within a longer-term decline associated with global warming."

Arctic sea ice acts as a barrier between the relatively warm Arctic Ocean and the much colder winter atmosphere, making it an important bellwether of climate change.

Its loss allows more ocean heat and moisture to enter the atmosphere, which can then affect pressure patterns, storm development and large-scale atmospheric circulation, impacting the weather further south.

Between 2024 and 2025, Arctic sea ice extent during the winter peak phase, from February to March, fell by 5.8%.

This was the largest year-to-year wintertime drop in the satellite record, which began in 1978.

While peak phase sea ice – the point where it reaches its maximum extent after growing over winter – recovered slightly in 2026, it still remained the second lowest extent recorded.

To analyse the results further, the team compared what was being observed by satellites to simulated comparable events using the latest climate change models.

Alessandro Silvano, co-author of the paper at the University of Southampton, said: "By identifying these analogous events, we found that such a sharp drop in 2025 was unusual, but physically plausible under current Arctic warming."

Analysing comparable events also allows researchers to anticipate what usually happens after a sharp winter sea ice drop such as the one observed in 2025.

Professor Simon Josey, co-author of the study at the National Oceanography Centre, said: "The model analogues suggest that, under current levels of Arctic warming, Arctic winter sea ice is more likely to fluctuate around a lower level over the next few years than quickly rebound to early 2020s conditions."

Meanwhile, Mr Chan said: "Short-term recoveries can temporarily obscure the longer-term direction of Arctic sea ice change.

"The low winter sea ice extents in 2025 and 2026 clearly show that Arctic sea ice loss has not stopped – it is continuing in a warming climate."

The study was funded by a UK Research and Innovation's Future Leaders Fellowship and the Natural Environment Research Council.