July 23: Two consecutive winters with record low Arctic sea ice have ended what appeared to be a slowdown in winter sea ice loss, restoring a statistically significant long term declining trend.
Researchers found that Arctic winter sea ice appeared relatively stable during the early 2020s, prompting questions over whether the rate of decline had slowed. However, new observations from 2025 and 2026 have reversed that conclusion.
The study found that the nearly 6 per cent decline in winter sea ice extent between 2024 and 2025 was the largest single year drop recorded since satellite monitoring began in the late 1970s. When data from the record low winters of 2025 and the near record low winter of 2026 were included, the 20 year trend once again showed a statistically significant decline.
Scientists analysed climate model simulations and found that a one-year decline of this magnitude is rare but consistent with current levels of Arctic warming. Similar drops occurred in about one out of every 100 simulated years under present day climate conditions, suggesting the event was unusual but physically plausible.
The researchers said the findings indicate that the apparent slowdown in winter sea ice loss during the early 2020s was likely a temporary pause caused by natural year to year variability rather than a reversal of the long term trend driven by climate change.
They cautioned that while Arctic sea ice will continue to fluctuate annually, continued global warming is expected to keep winter sea ice at lower average levels. Scientists are now monitoring whether a similar renewed decline will emerge in summer sea ice, which has also shown signs of slowing in recent years.