Researchers at University College London and Britain's National Oceanography Center say a change in wind direction could cause the water to spill into the north Atlantic, cooling Europe.
European Space Agency satellites show the sea surface in the studied area has risen by about 6 inches and the volume of fresh water has increased to about 10 percent of all the fresh water in the Arctic Ocean, a release from the agency's Paris headquarters said Monday.
Scientists say they believe the dome could be a result of strong arctic winds accelerating a large ocean circulation known as the Beaufort Gyre, causing the sea surface to bulge.
A change in those winds could cause the fresh water to spill into the rest of the Arctic Ocean and even reach the north Atlantic, researchers say, where it could slow a key ocean current, part of the Gulf Stream, that keeps Europe relatively mild compared with other areas at similar latitudes.
The result, they say, would be a cooler climate for much of Europe.