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Published online 29 November 2008 | Nature | doi:10.1038/news.2008.1262
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North Atlantic cold-water sink returns to life
Convective mixing resumes after a decade due to massive loss of Arctic ice.
Scientists have found evidence that convective mixing in the North Atlantic, a mechanism that fuels ocean circulation and affects Earth's climate, has returned after a decade of near stagnation – thanks, perhaps, to a dramatic loss of sea-ice in the Arctic during the summer of 2007.
Convective mixing, or 'overturning', of ocean waters at high latitudes helps to drive the Atlantic 'heat conveyor belt' that carries warm water northwards and cooler deep-water back south.
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Convective mixing is another evidence that nature with her natural mechanisms of stabilisation can control every defection. In this meaning defection are activities of men civilisation with its consequences. Of course natural skills for stabilize doesn't exculpate men. This kind of thinking would be naive. If we could think that nature will overcome and negate our debt, that would be a real end of rational, well, conscious and intelligent thought.
Natural skills? Convective mixing is a matter of physics. In the Northern North Atlantic the forces act within a water body that has an average of about three degrees Celsius. How much change is needed to cause a significant alteration of air temperatures? 80 years ago G. W. Littlehales (Bull.Nat.Res.Coun, 1927, No.61, p.26-31) explained the dimension as follows: ?a tract of ocean 450 miles square and one-tenth of a mile deep, in being reduced one degree in temperature, would give off enough heat to raise the temperature of the atmosphere 10 degrees over the whole of the United States up to a height of two miles?. Have we made a lot of progress since 1927? Difficult? From winter 1918/19 to winter 1921/20 the air temperature increased at Spitsbergen by more than eight degrees and continued to rise until 1939, as high as recently. It was the sea, says http://www.arctic-warming.com/