AFRICAN HUMID PERIOD

The pluvial episode in the latest pleistocene and early holocene (between about 14,500 and 5,500 calendar years BP) when the Sahara was much more vegetated than today with abundant savanna supporting a richer fauna, denser human populations and numerous perennial lakes. The African Humid Period is attributed to strengthening of the African monsoon in response to a gradual increase in summer season insolation. The onset and termination nevertheless appear to have been abrupt as a result of the crossing of a threshold in summer insolation receipt of about 4.2 per cent greater than at present. It was punctuated by a relatively arid phase (corresponding to the younger dryas stadial). The term Holocene African Humid Period should be reserved for the humid phase following this arid phase and prior to the change to late-Holocene hyperaridity.

[See alsoaridland: past environmental change, sapropel]