Human responses to hydroclimate fluctuations over the last 200 kyr in Ethiopia
- 1University of Cologne, Institute of Geography Education, Department of Education in Mathematics and Natural Sciences, Köln, Germany
- 2Addis Ababa University, School of Earth Sciences, Addis Ababa, Ethiopia
- 3University of Arizona, Department of Geosciences, Tucson AZ, USA
- 4Aberystwyth University, Department of Geography and Earth Sciences, Aberystwyth, UK
- 5School of Environmental Sciences, University of Hull, UK
- 6Berkeley Geochronology Centre, Berkeley, USA
- 7Georgia State University, Department of Geosciences, Atlanta, USA
- 8University of Potsdam, Institute of Geosciences, Potsdam, Germany
- 9Eberhard Karls Universität Tübingen, Department of Earth Sciences, Tübingen, Germany
- 10Department of Geography, University of Cambridge, UK
- 11British Geological Survey, Nottingham, UK & School of Biosciences, University of Nottingham, UK
- 12University of Cologne, Institute of Geography, Cologne, Germany
- 13Institute at Brown for Environment & Society, Brown University, Providence RI, USA
- 14University of Oxford, School of Archaeology, Oxford, UK
- *A full list of authors appears at the end of the abstract
Humans have been adapting to more demanding habitats in the course of their evolutionary history. Nevertheless, environmental changes coupled with overpopulation naturally limit competition for resources. In order to find such limits, reconstructions of climate and population changes are increasingly used for the continent of our origin, Africa. However, continuous and high-resolution records of climate-human interactions are still scarce.
Using a 280 m sediment core from Chew Bahir*, a wide tectonic basin in southern Ethiopia, we reconstruct the paleoenvironmental conditions during the development of Homo sapiens. The complete multiproxy record of the composite core covers the last ~600 ka , allowing tests of hypotheses about the influence of climate change on human evolution and technological innovation from the Late Acheulean to the Middle/Late Stone Age, and on dispersal within and out of Africa.
Here we present results from the uppermost 100 meters of the Chew Bahir core, spanning the last 200 kiloyears (ka). The record shows two modes of environmental change that are associated with two types of human mobility. The first mode is a long-term trend towards a more arid climate, overlain by precession-driven wet-dry alternation. Through comparison with the archaeological record, humid episodes appear to have led to the opening of ‘green’ networks between favourable habitats and thus to increased human mobility on a regional scale. The second mode of environmental change resembles millennial-scale Dansgaard-Oeschger and Heinrich events, which seem to coincide with enhanced vertical mobility from the Ethiopian rift to the highlands, especially in the time frame between ~65–21 ka BP. The coincidence of climate change and human mobility patterns help to define the limiting conditions for early Homo sapiens in eastern Africa.
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* cored in the context of HSPDP (Hominin Sites and Paleolakes Drilling Project) and CRC (Collaborative Research Centre) 806 “Our way to Europe”
(names above) & Emma Pearson, Martin H. Trauth, Célin Vidal, Finn Viehberg, Ralf Vogelsang
How to cite: Schäbitz, F., Foerster, V., Asrat, A., Cohen, A. S., Chapot, M. S., Dean, J. R., Deino, A., Deocampo, D. M., Duesing, W., Günter, C., Junginger, A., Kaboth-Bahr, S., Lamb, H. F., Lane, C., Leng, M. J., Opitz, S., Lupien, R., Roberts, H. M., Bronk Ramsey, C., and Rusell, J. and the HSPDP and CRC806 Science team: Human responses to hydroclimate fluctuations over the last 200 kyr in Ethiopia, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-11488, https://doi.org/10.5194/egusphere-egu2020-11488, 2020
