In the film The Day After Tomorrow, why did the weather change?
As GLH writes, Roland Emmerich based his story on a contested theory that the melting of polar ice may change the thermohaline circulation, a.k.a the oceanic conveyor belt. It works like this: The warm and salty (thermo means temperature and -haline means, salt) water from the gulf of Mexico, moves toward Norway, forming what is called the Gulf Stream. At about latitude 71 north, at the north of Norway, the water is now about 4 C and this is the temperature at which water is the heaviest. In fact, this is the temperature at the seabed of all oceans and even, deep lakes, simply because denser water sinks. Since that water is more salty than the polar one, it is even denser and sinks under less salty water of the same temperature. That creates a subsea current that moves south, across the equator, into the south Atlantic, the Indian ocean, the Pacific, and form that nearly thousand years cycle known as the oceanic conveyor belt that mixes all the water of all oceans. The contested theory
