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Sea ice in the Sea of Okhotsk

Updated on 30 June 2017
Global Environment and Marine Department

It is virtually certain that the maximum sea ice extent* in the Sea of Okhotsk follows a long-term trend of reduction by which an area equivalent to 4.4% of the sea's total area is lost per decade.

Maximum sea ice extent (1971 -2017) in the Sea of Okhotsk

Time-series representations of maximum sea ice extents in the Sea of Okhotsk from 1971 to 2017.


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 followed a long-term downward trend from 1970/1971 to 2016/2017. The sea ice extent has decreased by 0.069 [0.036 - 0.102] x 106 km2 per decade (the numbers in square brackets indicate the two-sided 95% confidence interval), which equates to a loss of 4.4 [2.3 - 6.5]% of the total sea area per decade.

Global warming may have contributed to this trend. However, only around 40 years of data on sea ice extent are available, which is insufficient for evaluation of the relationship between global warming and reduced sea ice extent in the Sea of Okhotsk. Accordingly, longer-term data are required.

*Maximum sea ice extent: the largest sea ice extent during the year