How the Earth Was Made (2009)

S2E12 America's Ice Age

Earth has experienced multiple Ice Age eras across its long history, each triggered by tiny shifts in its orbit and rotational tilt. These subtle variations in the planet's path around the sun can plunge the world into deep freezes that last for millennia. The program explores how long these icy periods persist, the conditions that end them, and predicts when Earth might face its next glacial chapter.