African rainfall variability: Palaeo insights into the climate history of our hominid ancestors and the monsoon response to a warmer future

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Monsoon precipitation controls the lives of over one billion of the world's poorest people. The situation is acute in the Sahel where annual rainfall is exceptionally variable. In the late 20th century the region suffered catastrophic drought in which precipitation declined by ~40%, with devastating effects as highlighted by Live Aid. Changes in rainfall over geological timescales were even more extreme. At times the Sahara Desert region was a vegetated landscape cross-cut by vast lakes and rivers inhabited by hippopotamuses. At others the desert extended well beyond present limits. What role did these dramatic past changes in rainfall play in the diversification and migration patterns of our hominid ancestors? What lessons can we learn from the palaeo-record to help predict the response of rainfall in the region to warming over coming centuries? Model predictions of future climate diverge. To address these questions we need well-dated records of change in both (i) continental hydroclimate and (ii) the moistures sources for the African monsoons: the Atlantic and Indian Oceans. You will exploit Ocean Drilling Program (ODP) marine drill-cores to test competing hypotheses of the land-ocean-atmospheric teleconnections involved by focusing on strategic past intervals of known warmth and/or hominid turnover/migration.