Human Saga

End of the African Humid Period and Desertification of the Sahara

c. 3500–2700 BCE·Environment & climate·Sahara (North Africa)·
c. 3500–2700 BCEDate
Environment & climateCategory
0Empires active
Date
c. 3500–2700 BCE
Category
Environment & climate
Region
Sahara (North Africa)
Era
Prehistory
Significance

Driven by gradual changes in Earth's orbital geometry that weakened the West African and North African monsoons, the 'Green Sahara' of the early-to-mid Holocene gave way to the modern desert.

Lakes, rivers and savanna that had supported hippos, elephants, giraffes and herds of cattle dried out, and the region's pastoralist populations were displaced southward and toward the Nile Valley. Many researchers argue the termination was abrupt in places, unfolding over a few centuries (some estimates as short as a century or two), though pollen and lake-sediment records such as those from Lake Yoa in Chad indicate a more gradual decline in some areas; the timing also varied regionally, ending earlier in the north and east. This environmental transformation concentrated human settlement along the Nile and other water sources, a demographic squeeze that scholars link to the consolidation of Nile Valley societies and the long-distance dispersal of cattle-keeping peoples. The vivid rock art of sites such as Tassili n'Ajjer preserves a visual record of the vanished wetter world.

See the world map in c. 3500–2700 BCE →More environment & climateThe Prehistory era

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The wider story

A New Green History of the World

Clive Ponting

The classic accessible account of how environment and climate have shaped human history.

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