Climate Change Caused Human Migration From Africa

via ScienceDaily.com

New evidence has been uncovered that suggest the primary reason for the migration of early human populations from Africa between 135,000 and 90,000 years ago was a series of severe and unprecedented droughts in Eastern Africa. Core samples from southeastern Africa's Lake Malawi, one of the world's deepest lakes, dropped almost 600 meters over the drought period. These samples show that the amount of vegetation and animal life much reduced from both earlier periods and their current diversity.

Present day Africa's lush vegetation and wildlife returned to the area around 70,000 years ago, and the lake refilled at that time to near its current level of 700 meters. University of Arizona researcher Steven Cohen compared the rainfall patterns area around the lake today to the southeastern United States, but during the drought period 100,000 years ago, these precipitation patterns would have been much more like the southwestern US's Sonora Desert region around the city of Tucson, AZ.