During the late Pleistocene (~125-10,000 years ago), the African continent experienced major fluctuations in climate, from warm and humid to very dry and cold conditions. How anatomically modern humans adapted biologically and culturally to these changes has been a subject of considerable interest and significance. For example, some scholars argue that the cold, dry conditions of 70-60 ka may have been the context of early Later Stone Age/Upper Paleolithic technological and social innovations that allowed Homo sapiens to leave Africa during subsequent warm periods to populate Eurasia and eventually the Americas. Others suggest similar cold and arid conditions during the last glacial maximum ~ 20-11,000 years ago depopulated much of Northern and Eastern Africa until warmer and wetter conditions of the early Holocene allowed for the rapid migration of hunter-gatherers into former deserts and other diverse environments..

During cold, dry periods, where did people live? How did their behavior change? In comparison to research on major population dispersals during warm and humid periods, little attention has been directed at identifying potential refugia, reconstructing their prehistoric environments, checking whether people lived there during prehistoric arid periods, and examining how they used local resources. Modern and ancient climate and circulation data suggest that Southwestern Ethiopia captured significant rainfall during arid periods when much of Northern and Eastern Africa had desert conditions. SW Ethiopia, with forest patches and resources absent elsewhere in the Horn, may have constituted a refugium for Northern and Eastern African human populations 70-60 ka and 20-11 ka. To evaluate this hypothesis, the researchers propose to gather archaeological and paleoclimatic data for the period bracketing the Last Glacial Maximum (>30-5 ka), to test whether Southwestern Ethiopia was a refugium during this hyperarid period, and provide analogical information to guide future research on earlier arid periods.

The group will use multiple, independent lines of evidence to create chronologically secure sequences of environmental change and human behavior for a little-studied region of potentially major significance to the survival of African human populations of the late Quaternary. The research will also be relevant to other archaeological/anthropological issues: such as: 1) environments and human behaviors in previous and subsequent arid periods in Africa, 2) global comparisons of Pleistocene refugia, 3) environmental and social contexts of subsistence change prior to plant domestication, and 4) the origins of the enormous genetic, linguistic, and cultural diversity of today's peoples of the Horn of Africa.

This project will also promote international collaboration between American, European, and Ethiopian scholars, and will stimulate the development of Ethiopian research and education by involving senior Ethiopian scholars and graduate students. The research group will work with local people to create archaeology exhibits and enhance other displays in 3 rural museums, improving local Ethiopians' ability to contribute to and access information about prehistory and cultural heritage. Proposed ecological studies of threatened natural areas may also contribute to their conservation. Finally, this project will raise the profile of the cultures, history, and prehistory of southern Ethiopia, a region long marginalized in Ethiopian history. Finally, this research will contribute to global discussions of sudden climatic change and human responses past and present, a topic vital to food security and political stability around the world.

National Science Foundation (NSF)
Division of Behavioral and Cognitive Sciences (BCS)
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John E. Yellen
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University of Florida
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