Arctic Ocean continues to freshen up

Fish accustomed to the salty water of the Arctic may have to think about finding a new home.
As a result of global warming, the Arctic Ocean has been getting less salty over the past half century and the trend looks set to continue. The culprits are a massive increase in rainfall over the Arctic and faster melting of sea ice and glaciers.
Bruce Peterson of the Marine Biological Laboratory in Woods Hole, Massachusetts, and his team gathered decades' worth of meteorological, river, sea-ice and glacier data from the Arctic region and used it to calculate the increase in fresh water input into the ocean. They calculated that increased rainfall and river outflow between 1965 and 1995 dumped an extra 20,000 cubic kilometres of freshwater into the ocean - equivalent to 40 years' flow from the Mississippi river. Melting sea ice contributed a further 15,000 km3 and glaciers 2000 km3. This is consistent with the observed decrease in the salinity of the Arctic Ocean over the same period.
"Our results show that there has been a global redistribution of fresh water, which is probably related to global warming," Peterson says.
Changes in patterns of atmospheric pressure over the North Atlantic, known as the North Atlantic Oscillation, appear to have speeded up the transfer of moisture from low to high latitudes. Climate models indicate that the effect will intensify, raising concerns about the flow of deep waters through the North Atlantic - driven by the sinking of dense, salty water at high latitudes. Disrupting this current could cause temperatures to plunge across northern Europe.
From issue 2567 of New Scientist magazine, 05 September 2006, page