The Sahara was green
Between about 11,000 and 5,000 years ago the Sahara held lakes, grasslands, and people.
Established2 min read
Lake sediments, fossil pollen, and the bones of hippos and crocodiles sit under what is now dune. Rock art in the massifs shows herders and swimmers. Climate models and ocean cores agree that a stronger West African monsoon, driven by orbital changes in summer sunlight, pushed rainfall hundreds of kilometres north.
The wet phase is called the African Humid Period. It was not one unbroken jungle. It pulsed, and in many records it ended quickly, over centuries rather than millennia, as the monsoon retreated and vegetation feedbacks flipped the region back to sand.
Caveats
- Dates differ by longitude and by what is being dated: a lake, a grassland, a last human camp.
- 'Green' means savanna, lakes, and scrub in much of the basin, not a continuous rainforest.
Sources
- 1deMenocal P. et al.. Abrupt onset and termination of the African Humid Period. Quaternary Science Reviews 19, 2000.