Ancient drought 'changed history'
Scientists have identified a major climate crisis that struck Africa about 70,000 years ago and which may have changed the course of human history. The evidence comes from sediments drilled up from the beds of Lake Malawi and Tanganyika in East Africa, and from Lake Bosumtwi in Ghana. It shows equatorial Africa experienced a prolonged period of drought. It is possible, scientists say, this was the reason some of the first humans left Africa to populate the globe.