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

季风降水控制着世界上10多亿最贫困人口的生活。萨赫勒地区的情况尤为严重，那里的年降雨量变化无常。20世纪后期，该地区遭受了灾难性的干旱，降水量下降了约40%，其破坏性影响正如Live Aid所强调的那样。降雨在地质时间尺度上的变化更为极端。有时，撒哈拉沙漠地区是一片植被繁茂的景观，被河马栖息的巨大湖泊和河流交叉。在另一些地方，沙漠远远超出了目前的极限。过去这些戏剧性的降雨变化在人类祖先的多样化和迁移模式中发挥了什么作用？我们可以从古记录中学到什么教训，以帮助预测未来几个世纪该地区降雨对变暖的反应？模型对未来气候的预测存在分歧。为了解决这些问题，我们需要(1)大陆水文气候和(2)非洲季风的水汽来源（大西洋和印度洋）的准确年代变化记录。您将利用海洋钻探计划（ODP）的海洋钻探岩心，通过关注已知温暖和/或人类更替/迁移的战略过去间隔，来测试陆地-海洋-大气遥相关的相互竞争的假设。

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.