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Prehistoric North Africa

Prehistory of North African region

  • 13 min read
  • 7 chapters
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IZN1SEN · CC BY-SA 4.0

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Through Neolithic, Iron Age and Glacial period

Climate

Human habitation in North Africa has been greatly influenced by the climate of the Sahara (currently the world's largest warm desert), which has undergone enormous variations between wet and dry over the last few hundred thousand years. This is due to a 41,000-year Axial tilt cycle in which the tilt of the earth changes between 22° and 24.5°. At present (2000 AD), we are in a dry period, but it is expected that the Sahara will become green again in 15,000 years (17,000 AD).

During the last glacial period, the Sahara was much larger than it is today, extending south beyond its current boundaries. The end of the glacial period brought more rain to the Sahara, from about 8000 BC to 6000 BC, perhaps because of low pressure areas over the collapsing ice sheets to the north. Once the ice sheets were gone, the northern Sahara dried out. In the southern Sahara, the drying trend was initially counteracted by the monsoon, which brought rain further north than it does today. By around 4200 BC, however, the monsoon retreated south to approximately where it is today, leading to the gradual desertification of the Sahara. The Sahara is presently as dry as it was about 13,000 years ago.

These conditions are responsible for what has been called the Sahara pump theory. During periods of a wet or "Green Sahara", the Sahara becomes a savanna grassland and various flora and fauna become more common. Following inter-pluvial arid periods, the Sahara area then reverts to desert conditions and the flora and fauna are forced to retreat northwards to the Atlas Mountains, southwards into West Africa, or eastwards into the Nile Valley. This separates populations of some of the species in areas with different climates, forcing them to adapt, possibly giving rise to allopatric speciation.

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