During the Pleistocene, glaciers came and went, resulting in a series of ice ages punctuated by warmer periods. There were at least 20 cycles of this advance and retreat. During the ice ages, global temperatures were 5 degrees centigrade cooler than today and it was much drier, since much of the world's water was locked up in massive ice sheets. The expansion of the deserts and the action of glaciers grinding up rocks meant that dust storms would have been a lot more common in the Pleistocene than they are now. Our species evolved during this epoch.
Began: 2.6 million years ago
Ended: 11.7 thousand years ago
During this period the following extinction level events are thought to have occurred.