GNV News, 29 July 2026

Some studies had shown research data suggesting that the pace of winter sea ice loss appeared to slow from the late 2000s through the early 2020s.

However, the latest 2026 study published in the Proceedings of the National Academy of Sciences of the United States of America (PNAS), now indicates that this view may have been mistaken. With the winter sea ice extent in 2025 reaching the smallest area ever recorded by satellite, the declining trend has been confirmed once again. Moreover, in 2026 the extent remained at almost the same record-low level as in 2025, making for two consecutive years of exceptional results.

This study reanalyzed the long-term changes in Arctic sea ice by adding the 2025 and 2026 data to recent observational records. It concluded that the phenomenon previously interpreted as a slowdown in sea ice loss from the late 2000s through the early 2020s does not indicate a long-term recovery trend, but is highly likely to have been merely a temporary fluctuation caused by internal variability (natural variability).

The decline of Arctic sea ice is mainly driven by long-term warming due to increasing greenhouse gases, but the way this change appears is thought to be strongly influenced by internal variability. Internal variability refers to fluctuations that arise naturally within the climate system, caused by processes internal to the atmosphere, ocean, and other components.

In practice, Arctic sea ice varies greatly from year to year. Influenced by air temperature, wind patterns, ocean currents, and other factors, it increases and decreases repeatedly over the short term. As a result, if you look only at data over spans of a few years, it can sometimes appear as though the decline has stopped or is even improving. Over a timescale of several decades, however, the long-term downward trend has not changed.

Not only in the Arctic but across the climate system as a whole, complexity and internal variability produce large short-term fluctuations. Therefore, judging long-term trends solely on the basis of data covering only a few years can be misleading.

Learn more about the Arctic → “Warming in the Arctic on the Rise”

Learn more about climate change → “The Reality of Exceeding 1.5°C: Global Climate Change Issues, Responses, and Media Coverage in Japan”