New 90 minute podcast from the Long Now Foundation. Stefan Kroepelin on “Civilization’s Mysterious Desert Cradle: Rediscovering the Deep Sahara” (.mp3 link. Starts at 4:10).

Kroepelin has survived every kind of desert hardship to discover the climate and cultural history of northern Africa. He found that the “Green Sahara” arrived with monsoon rains 10,500 years ago, and people quickly moved into the new fertile savannah. There they prospered as cattle pastoralists — their elaborate rock paintings show herds of rhinoceros and scenes of prehistoric life — until 7,300 years ago, when gradually increasing desiccation drove them to the Nile river, which they had previously considered too dangerous for occupation. To manage the Nile, the former pastoralists helped to invent a Pharaonic state 5,100 years ago. Its 3,000-year continuity has never been surpassed. Kroepelin, a climate scientist at the University of Cologne, is a dazzling speaker with hair-raising stories.