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Phoenix666 writes:

The Gulf Stream, which keeps Europe's climate mild, is slowing down.

The gradual but accelerating melting of the Greenland ice-sheet, caused by human-made global warming, is a possible major contributor to the slowdown. Further weakening could impact marine ecosystems and sea level as well as weather systems in the US and Europe.

"It is conspicuous that one specific area in the North Atlantic has been cooling in the past hundred years while the rest of the world heats up," says Stefan Rahmstorf of the Potsdam Institute for Climate Impact Research, lead author of the study to be published in Nature Climate Change. Previous research had already indicated that a slowdown of the so-called Atlantic meridional overturning circulation might be to blame for this. "Now we have detected strong evidence that the global conveyor has indeed been weakening in the past hundred years, particularly since 1970," says Rahmstorf.

Because long-term direct ocean current measurements are lacking, the scientists mainly used sea-surface and atmospheric temperature data to derive information about the ocean currents, exploiting the fact that ocean currents are the leading cause of temperature variations in the subpolar north Atlantic. From so-called proxy data—gathered from ice-cores, tree-rings, coral, and ocean and lake sediments—temperatures can be reconstructed for more than a millennium back in time. The recent changes found by the team are unprecedented since the year 900 AD, strongly suggesting they are caused by human-made global warming.

Time to go long in wool futures?