Wet spells in the Sahara may have opened the door for early human migration. According to new evidence, water-dependent trees and shrubs grew there between 120,000 and 45,000 years ago. This suggests that changes in the weather helped early humans cross the desert on their way out of Africa.
The Sahara would have been a formidable barrier during the Stone Age, making it hard to understand how humans made it to Europe from eastern Africa, where the earliest remains of our hominin ancestors are found.
via newscientist.com
Hat tip to Instapundit.