The movie The Day After Tomorrow depicts a catastrophic climate shift to global cooling, which is referred to as the new ice age. In the movie, melting of polar ice caused by global warming disrupts the North Atlantic current, rapidly dropping the ocean temperature, ultimately leading to the freezing of the ocean on a global scale. Although this over-the-top effect portrayed by this fictional film contains little scientific truth, many scientists are studying a global ice age during the Cryogenian, a geologic period that lasted from 720 to 635 million years ago.