"most recent one" . "African Humid Period" . "Holocene Humid Phase" . "Higher precipitation rates at the beginning" . . "natural changes" . "\\\"green\\\" Sahara" . "Climate changes and/or overgrazing around 6000 BC began to desiccate the pastoral lands of Egypt" . "natural climate changes" . "desiccation of the Sahara" . "Egyptian climate was much less arid than it is today" . . "African Humid period" . "Wet Sahara" . . "Intense aridification" . . "African humid period" . "Humid Period" . "verdant vegetation and diverse wildlife" . "The Saharan area was wetter" . . . "natural precipitation change" . "Saharan wet phase" . "desiccation of the Sahara in c. 3500 BC" . . . "Gap has become wet enough to support rainforest, thus eliminating the savanna." . "significant decline in rainfall" . "precipitation was considerably higher" . "3900 BCE" . "African humid period" . "desiccation of the Sahara in c. 3500 BCE" . "5,500 years ago" . "As the Sahara dried out over the last few thousand years" . "more humid climatic context" . "wet period" .