11,000 years ago, at the beginning of the Holocene, today’s hyper-arid Sahara desert was dotted with large and small lakes, savannah and grassland and in some regions even humid tropical forest. Due to a strengthened African monsoon triggered by strong orbital forcing i.e. summer insolation, more humid conditions compared to today, prevailed in Northern and Central Africa.
Pronounced changes in African climate, deserts and tropical rain forest over the last glacial cycles presumably affected human’s way out of Africa. These changes were induced by large changes in ice masses, ocean circulation and monsoon dynamics which, in turn, were triggered by variations in the Earth orbit around the sun and subsequent alteration of meridional insolation gradients.