Tropical African climate has oscillated between markedly wetter and drier conditions on all timescales in response to global climate disturbances. A step-like increase in aridity over the past 3 Ma has been primarily paced by orbital cycles coupled with the onset and amplification of high-latitude glacial cycles. On the 104 –103 -ka timescales, observed changes imply interactions between insolation, sea-surface conditions and vegetation. High-frequency variations could be linked to oscillations in major atmospheric circulation modes, in solar output, or to major volcanic events.
Tropical Africa, palaeoclimates, palaeohydrology, Pliocene, Quaternary