Updated on 30 Jun. 2026
Japan Meteorological Agency
It is virtually certain that the maximum sea ice extent in the Sea of Okhotsk follows a long-term decreasing trend, at a rate of 3.7% of the sea's total area per decade.
Time-series representations of maximum sea ice extents in the Sea of Okhotsk from 1971 to 2026.
Although the maximum sea ice extent in the Sea of Okhotsk shows large interannual variations because it is highly sensitive to changes in regional air temperature, wind and sea surface temperature, it is virtually certain that it has followed a long-term downward trend from 1970/1971 to 2025/2026. The sea ice extent has decreased by 0.059 [0.034-0.084] x 106 km2 per decade (the numbers in square brackets indicate the two-sided 95% confidence interval), equivalent to 3.7 [2.1-5.3]% of the total sea area per decade.
Global warming may have contributed to this trend. However, longer-term data are required for evaluation of the relationship between global warming and the reduced sea ice extent observed in the Sea of Okhotsk.
*Maximum sea ice extent: the largest sea ice extent in the winter