EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Northern Hemisphere Glaciation, African Climate and Evolution

Martin H. Trauth1, Asfawossen Asrat2, Nadine Berner3, Faysal Bibi4, Verena Foerster5, Matt Grove6, Stefanie Kaboth-Bahr1, Mark A. Maslin7, Manfred Mudelsee8, and Frank Schaebitz5
Martin H. Trauth et al.
  • 1University of Potsdam, Institute for Geosciences, Potsdam, Germany (
  • 2Addis Ababa University, School of Earth Sciences, Addis Ababa, Ethiopia
  • 3Gesellschaft für Anlagen- und Reaktorsicherheit (GRS) gGmbH, Garching, Germany
  • 4Museum für Naturkunde, Leibniz Institute for Evolution and Biodiversity Science, Berlin, Germany
  • 5University of Cologne, Institute of Geography Education, Cologne, Germany
  • 6University of Liverpool, Department of Archaeology, Liverpool, UK
  • 7University College London, Geography Department, London, UK
  • 8Climate Risk Analysis, Bad Gandersheim, Germany

The hypothesis of a connection between the onset (or intensification) of Northern Hemisphere Glaciation (NHG), the stepwise increase in African aridity (and climate variability) and an important mammalian (including hominin) species turnover is a textbook example of the initiation of a scientific idea and its propagation in science. It is, however, also an example of the persistent popularity of a hypothesis despite mounting evidence against it. The first part of our work analyzes of the history of the scientific idea by seeking its roots, including coincidental meetings and exchanges between of scientists, at project meetings, conferences and workshops. The consequences of this idea are examined and its influence on subsequent scientific investigations both before and after it has been falsified. In the second part of our investigation, we examine why the idea that the high latitudes have a major control on the climate of the low latitudes and thus early human evolution persists. For this purpose, an attempt is made to understand the original interpretation of the data, with special consideration of the composition of the scientific team and their scientific backgrounds and persuasions. Some of the key records in support of the hypothesis of a step-wise transition will be statistically re-analyzed by fitting change-point models to the time series to determine the midpoint and duration of the transition – in case such a transition is found in the data. A critical review of key publications in support of such a connection and a statistical re-analysis of key data sets leads to three conclusions: (1) Northern Hemisphere Glaciation is a gradual process between ~3.5–2.5 Ma, not an abrupt onset, either at ~2.5 Ma, nor at ~2.8 Ma, or any other time in the Late Cenozoic Era, (2) the trend towards greater aridity in Africa during this period was also gradual, not stepwise in the sense of a consistent transition of a duration of ≤0.2 Ma, and (3) accordingly, a step-wise change in environmental conditions cannot be used to explain an important mammalian (including hominin) species turnover.

How to cite: Trauth, M. H., Asrat, A., Berner, N., Bibi, F., Foerster, V., Grove, M., Kaboth-Bahr, S., Maslin, M. A., Mudelsee, M., and Schaebitz, F.: Northern Hemisphere Glaciation, African Climate and Evolution, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-805,, 2021.

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