Heat from Below: How the Ocean is Wearing Down the Arctic Sea Ice

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The influx of warmer water masses from the North Atlantic into the European marginal seas of the Arctic Ocean plays a significant role in the marked decrease in sea-ice growth, especially in winter.

The influx of warmer water masses from the North Atlantic into the European marginal seas of the Arctic Ocean plays a significant role in the marked decrease in sea-ice growth, especially in winter. Sea-ice physicists from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI), together with researchers from the US and Russia, now present evidence for this in two new studies, which show that heat from the Atlantic has hindered ice growth in the Barents and Kara Seas for years. Furthermore, they demonstrate that the invasion of warm Atlantic water masses further east, at the northern edge of the Laptev Sea, can have such a long-term impact on the increase in ice thickness that the effects are evident a year later, when the ice has drifted towards Greenland via the North Pole and leaves the Arctic through Fram Strait. This study also includes data from the MOSAiC expedition.

Marine researchers refer to the increasing influx of warm Atlantic water masses into the Arctic Ocean as ‘Atlantification’. To date, this process has mainly been investigated from an oceanographic perspective. In two new studies, AWI sea-ice physicists have, for the first time, estimated the effects of the input of heat on the sea-ice growth in the Arctic. Of note here: in those places where the sea ice completely melts in summer, in the following winter the sea releases especially large amounts of heat into the atmosphere. As a result, the sea freezes so rapidly that it compensates for the summertime ice losses. “Young, thin sea ice conducts heat significantly better than thick ice, and therefore less effectively protects the sea from cooling. At the same time, more water freezes on the bottom of the ice, which is why thin ice grows more quickly than thick ice,” explains AWI sea-ice physicist Dr Robert Ricker.

Read more at: Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research

View of the area where the MOSAiC ice floe was located. (Photo Credit: Esther Horvath)