Changing salt levels in the ocean reflect human-induced climate change

Louise Gray, The Telegraph 24 Oct 08;

Global warming is changing levels of salt in the ocean leading to different weather patterns on land, meteorologists have found.

The Met Office and researchers at the University of Reading looked at levels of salinity in the Atlantic Ocean.

In the subtropical zone salt has increased to a level outside natural variablitity over the last 20 years, suggesting less rainfall and increased evaporation caused by human-induced climate change.

However in the North Atlantic, where there are more changeable weather patterns, an increase in salt levels was put down to natural variation.

This reverses previous fears that fresh water from the melting ice caps is diluting the north seas at such a rate it will reverse the warm Gulf Stream current, leading to a significantly colder climate for Europe - although over the long run the North Atlantic is expected to become less salty.

Peter Stott, head of climate monitoring and attribution at the Met Office and leader of the study, said there is relatively little information on the affect of global warming on the oceans.

He said understanding levels of salt in the ocean could help to project how the climate will change on land.

He said: "Knowing how our oceans are changing over what are essentially vast data-sparse areas is important.

"It provides us with a window on changes in the hydrological cycle and gives us more certainty in projections of rainfall as the climate changes."