Weather or Not

If you watched the movie, “The Day After Tomorrow,” you saw the cartoon version of what would happen if the circulation of the North Atlantic suddenly slowed or stopped.

The movie was built on the hypothesis that if the ocean were to cease transporting warm water from the tropics toward the Poles, all form of hell – and ice – would break loose. In the movie, it was not a particularly good time to be in Manhattan.

While the movie should not be taken seriously, the Greenland ice core record does show evidence of an abrupt climate shift roughly 8,200 years ago during a period of glacial melt.

A paper published this week in the journal “Sciencexpress” suggests that a major change in the North Atlantic circulation was behind the dramatic and sudden onset of the cold spell.

The paper appears to support some earlier research holding that the cold spell was tied to a massive influx of freshwater from a melting glacial lake in North America, just south of Hudson Bay, known as Lake Agassiz.

The rapid injection of such a colossal quantity of water into the North Atlantic might have been sufficient to interrupt the Atlantic heat-transport system.

Lead author Helga Flesche Kleivin, of the University of Bergen, Norway, and her colleagues noted that this was a case in which large-scale changes in the natural world matched computer simulations.

The findings are of import, they say, given all the concerns over how warming will affect the Greenland ice sheet .