Gulf Stream

If the Gulf Stream were somehow to shut down—something that it is hypothesized would happen due to climate change, as Greenland’s melting glaciers dump a ton of fresh water into the North Atlantic, disrupting the current¹—it would not, it turns out, plunge Europe into a new ice age. That, at least, is the contention of Richard Seager, a climate scientist at Columbia University’s Lamont-Doherty Earth Observatory. He argues that European winters are 15 to 20 degrees warmer than North American winters at the same latitudes for two reasons: one, the effect of the Rocky Mountains on air currents, which bring cold air south in North America but warm air north into western Europe; and two, the seasonal release of heat stored by the Atlantic Ocean itself. The Gulf Stream itself is responsible for only a few degrees’ warming; if it were taken away, the cooling effect would not be enough to overwhelm the much larger warming effect from climate change.