A huge pool of fresh water in the Arctic Ocean is expanding and could lower Europe’s temperature by causing a mild ocean current to slow down, British scientists say.
Using satellites to measure sea surface height from 1995 to 2010, scientists from University College London and Britain's National Oceanography Center found that the western Arctic's sea surface has risen by about 15 centimetres since 2002.
The volume of fresh water has increased by at least 8,000 cubic kilometers, or about 10% of all the fresh water in the Arctic Ocean. The fresh water comes from melting ice and river run-off.
The rise could be due to strong Arctic winds increasing an ocean current called the Beaufort Gyre, making the sea surface bulge upwards.
The Beaufort Gyre is one of the least understood bodies of water on the planet. It is a slowly swirling body of ice and water north of Alaska, about 10 times bigger than Lake Michigan in the United States.
Some scientists believe the natural rhythms of the gyre could be affected by global warming which could have serious implications for the ocean's circulation and rising sea levels.
Climate models have suggested that wind blowing on the surface of the sea has formed a raised dome in the middle of the Beaufort Gyre, but there have been few in-depth studies to confirm this.
If the wind changes direction, which happened between the mid-1980s to mid-1990s, the pool of fresh water could spill out into the rest of the Arctic Ocean and even into the North Atlantic Ocean, the study said.
This could cool Europe by slowing down an ocean current coming from the Gulf Stream, which keeps Europe relatively mild compared with countries at similar latitudes.
"Our findings suggest that a reversal of the wind could result in the release of this fresh water to the rest of the Arctic Ocean and even beyond," Katharine Giles at UCL's Center for Polar Observation and Modelling and lead author of the study, said on 22 January. The study was published in the journal Nature Geoscience.
The team plans to investigate further the relationship between sea-ice cover and wind changes.