New research suggests changes in the Arctic Ocean could affect the climate of coastal Europe.
"Large regional changes could be in store if the ocean circulation changes," said Laura de Stern of the Royal Netherlands Institute for Sea Research.
De Stern is the lead author of a major international study on the northern seas released Tuesday.
One of the report's findings is that the Arctic Ocean holds a vast pool of relatively fresh water. Much of it comes from rivers such as Canada's Mackenzie and Russia's Lena.
That pool — now larger than 7,500 cubic kilometres — is contained in the Canada Basin off the coast of the Northwest Territories and Yukon by a pattern of wind circulation called the Beaufort Gyre.
But the gyre changes in strength. When it weakens, the fresher water it has kept concentrated in the Arctic is released to filter into the North Atlantic.
"This is a natural phenomenon," said contributor Mike Steele of the University of Washington.
"[The gyre] tends to collect it in some years and in other years the gyre will shrink and then it'll sort of release the fresh water."
Recent data suggests that climate change may be increasing the amount of fresh water pouring into the Arctic Ocean.
A study by Germany's Alfred Wegener Institute released in March found the upper layers of the northern ocean may already be 20 per cent less salty than they were in the 1990s.
The data points to increasingly larger and fresher releases of water from the Arctic Ocean into the North Atlantic.
"These Arctic outflow surges can significantly change the densities of marine surface waters in the extreme North Atlantic," said de Stern. "What happens next is hard to predict."
Ocean currents could be affected
Ocean currents, which are driven by differences in temperature and salinity between different pools of sea water, could be affected.
Ultimately, one of those currents, a giant undersea conveyor belt that moves warm water from the southern Atlantic north to Greenland and the coasts of Scandinavia and Great Britain, could be weakened.
The report suggests the climate of those countries could cool substantially as a result.
Steele warns that those concerns have yet to be backed up by data.
"It may have influence on the global ocean conveyor belt," he said. "Right now there's kind of a controversy about the importance of this fresh water coming out of the Arctic Ocean."
Scientists hope to get some of the answers later this year when they observe the latest fresh water release.
The question of whether climate change could have an impact on ocean currents has been asked before. Research has so far suggested those currents remain stable.
But most climate models predict the currents will weaken by 20 per cent by the end of the century.