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Abstract Despite more than half a century of hominin fossil discoveries in eastern Africa, the regional environmental context of hominin evolution and dispersal is not well established due to the lack of continuous palaeoenvironmental records from one of the proven habitats of early human populations, particularly for the Pleistocene epoch. Here we present a 620,000-year environmental record from Chew Bahir, southern Ethiopia, which is proximal to key fossil sites. Our record documents the potential influence of different episodes of climatic variability on hominin biological and cultural transformation. The appearance of high anatomical diversity in hominin groups coincides with long-lasting and relatively stable humid conditions from ~620,000 to 275,000 yearsbp(episodes 1–6), interrupted by several abrupt and extreme hydroclimate perturbations. A pattern of pronounced climatic cyclicity transformed habitats during episodes 7–9 (~275,000–60,000 yearsbp), a crucial phase encompassing the gradual transition from Acheulean to Middle Stone Age technologies, the emergence ofHomo sapiensin eastern Africa and key human social and cultural innovations. Those accumulative innovations plus the alignment of humid pulses between northeastern Africa and the eastern Mediterranean during high-frequency climate oscillations of episodes 10–12 (~60,000–10,000 yearsbp) could have facilitated the global dispersal ofH. sapiens. 

Abstract. The Neogene and Quaternary are characterized by enormous changes in globalclimate and environments, including global cooling and the establishment ofnorthern high-latitude glaciers. These changes reshaped global ecosystems,including the emergence of tropical dry forests and savannahs that are foundin Africa today, which in turn may have influenced the evolution of humansand their ancestors. However, despite decades of research we lack long,continuous, well-resolved records of tropical climate, ecosystem changes,and surface processes necessary to understand their interactions andinfluences on evolutionary processes. Lake Tanganyika, Africa, contains themost continuous, long continental climate record from the mid-Miocene(∼10 Ma) to the present anywhere in the tropics and has longbeen recognized as a top-priority site for scientific drilling. The lake issurrounded by the Miombo woodlands, part of the largest dry tropical biomeon Earth. Lake Tanganyika also harbors incredibly diverse endemic biotaand an entirely unexplored deep microbial biosphere, and it provides textbookexamples of rift segmentation, fault behavior, and associated surfaceprocesses. To evaluate the interdisciplinary scientific opportunities thatan ICDP drilling program at Lake Tanganyika could offer, more than 70scientists representing 12 countries and a variety of scientificdisciplines met in Dar es Salaam, Tanzania, in June 2019. The teamdeveloped key research objectives in basin evolution, source-to-sinksedimentology, organismal evolution, geomicrobiology, paleoclimatology,paleolimnology, terrestrial paleoecology, paleoanthropology, andgeochronology to be addressed through scientific drilling on LakeTanganyika. They also identified drilling targets and strategies, logisticalchallenges, and education and capacity building programs to be carried outthrough the project. Participants concluded that a drilling program at LakeTanganyika would produce the first continuous Miocene–present record fromthe tropics, transforming our understanding of global environmental change,the environmental context of human origins in Africa, and providing adetailed window into the dynamics, tempo and mode of biologicaldiversification and adaptive radiations.