Arctic rivers 'flowing faster'
January 21, 2005
The amount of fresh water entering the Arctic Ocean from the rivers that feed it is increasing, UK scientists report.
Writing in the journal Geophysical Research Letters, they say the increase is caused in part by human activities and is an early sign of climate change.
The rise in fresh water entering the Arctic Ocean could change the global distribution of water, the team says.
It could also affect the balance of the climate system itself and even possibly alter the behaviour of the Gulf Stream.
The team is from the Hadley Centre for Climate Prediction and Research, part of the UK Met Office.
Knock-on effects
The global hydrological cycle is the exchange of water between the land, the oceans and the atmosphere. The rate of the exchange is expected to increase as the Earth warms.
Part of the process is likely to mean more precipitation (hail, rain, sleet and snow) at higher latitudes, and so more water flowing down the rivers.
If the global water distribution changes, this could have important social and economic consequences. An altered hydrological cycle might conceivably have a profound cooling effect on north-west Europe as well.
The American Geophysical Union, publisher of the journal, says: "It could also alter the balance of the climate system itself, such as the Atlantic thermohaline circulation, a kind of conveyor belt.
"Cold water flows southward in the Atlantic at great depths to the tropics, where it warms, rises, and returns northward near the surface.
"This flow helps keep northern Europe at a temperate climate, whereas the same latitudes in North America are sparsely settled tundra or taiga."
The Hadley researchers compared data published in 2002 from observations of Siberian river flows with model simulations, to see whether they could identify a human influence on the increase in fresh water.
Further information can be found on the BBC News site.
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