Abstract

Historical and Quaternary palaeoenvironmental archives from northern and southern Africa indicate phases of extreme wet/dry conditions of much greater amplitude than the variability seen in recent years. These phases were accompanied by massive changes to lakes, wetlands, and vegetation. Such variability of hydroclimate has also been strongly linked to ancient human adaptation and migration. However, the spatial pattern of precipitation variability and its dominant driving forces are still debated. Prevailing hypotheses variously infer (1) insolation-controlled asymmetry of wet phases between hemispheres, (2) symmetric contraction and expansion of the tropical rainbelt, and (3) independent control on moisture available in Southern Africa via sea surface temperatures in the Indian Ocean. Here, I will explore these hypotheses using results from climate-model simulations covering the last glacial cycle (120 kyr) to investigate the long-term behaviour of the African rainbelt, and test these simulations against existing empirical palaeohydrological records. I will also discuss the potential impact of feedbacks between lakes/wetlands and climate for regional climate change.