Mesopotamia, which translates to "the land between the rivers," experienced the severe cold drought of 6200 B.C. This was an abrupt, short-lived cooling of the Earth's surface that was centered in Greenland, but affected other areas.
Before and after this cooling period, Mesopotamia had a "warm and wet" climate. This climate made Mesopotamia into a sort of "Garden of Eden" in the surrounding desert. The climate allowed for hunting and herding, or nomadic pastoralism. Learn more about Geography