Fresh Water Flow to Arctic Ocean Increasing
DURHAM, New Hampshire, December 19, 2002 (ENS) - The average annual discharge of fresh water into the Arctic Ocean from the six largest Eurasian rivers has increased seven percent since 1936, an international research team has found. The six rivers include three of the largest rivers on Earth, the Tenisei-Angara, the Ob, and the Lena - all in Russia.
The authors of "Increasing River Discharge to the Arctic Ocean," published in the December 13 issue of the journal "Science," correlated this increase in freshwater flow to historic patterns of climate change.
Based on the Intergovernmental Panel on Climate Change (IPCC) projections for global temperature rise, the authors predict that, if these patterns hold, there will be an 18 percent increase in river discharge over the next 100 years.
IPCC climate models project that the Earth will warm 1.4 to 5.8 degrees Celsius (2.5 to 10.8 degrees Fahrenheit) between 1990 and 2100, with most land areas warming more than the global average.
An increase of such magnitude may have "large-scale impacts" on the ocean circulation pattern that brings heat to the northern latitudes, the authors said.
The Russian State Hydrological Institute and the Potsdam Institute for Climate Impact Research in Germany collaborated with lead author Bruce Peterson from the Marine Biological Laboratory, an independent scientific institution in Woods Hole, Massachusetts. Co-authors from the Water Systems Analysis Group at the University of New Hampshire include Charles Vorosmarty, Richard Lammers, and Alex Shiklomanov.
"Too much freshwater leaking from the land into the Arctic Ocean could reduce or shift the patterns of Atlantic deep water formation and stall the ocean conveyor belt that helps to bring heat to the northern latitudes," explains Charles Vörösmarty, co-author and professor of Earth Sciences at the University of New Hampshire's Institute for the Study of Earth, Oceans, and Space.
"England, for example, without the beneficial effect of this ocean circulation, would plunge into a deep freeze due to its high latitude," he said.
In a self-perpetuating cycle, as temperatures warm globally, evaporation of surface water will increase and more moisture will be held in the atmosphere. This moisture will lead to more precipitation at high latitudes, such as the Arctic, and more river runoff.