Project leader: Dr. Arne Micheels

Publications

The project E1.10 is part of the Research Unit "UCCC - Understanding Cenozoic Climate Cooling" funded by the German Research Foundation. The DFG Research Unit UCCC is a collaboration with the Alfred-Wegener-Institut für Polar- und Meeresforschung in Bremerhaven, the Zentrum für Marine Umweltwissenschaften of the University of Bremen, the Max-Planck-Institut für Meteorologie in Hamburg, the Forschungszentrum Jülich, and the Laboratoire de Physique Atmospherique et Planetaire of the University of Liege in Belgium. The research activities of E1.10 focus basically on the climate of the Neogene (32 to 1.8 Ma) with special emphasis on the Late Miocene (11 to 7 Ma).

During the Tertiary (65 to 1.8 Ma), the global climate got successively cooler. The Late Miocene (11 to 7 Ma) belongs to the late phase of the Cenozoic climate cooling, but climate was still warm and humid as compared to today. The Alps just started to form and the uplift of the Tibetan Plateau still continued. However, the continent configuration was largely comparable to the modern situation. Because of the similarities, the Miocene can serve as a possible analogue for the future climate change. According to the global climate cooling, the vegetation experienced significant changes in the Tertiary until today (fig. 1), and we use the tool palaeoclimate modelling to analyse the driving processes (fig. 2). On the one hand, we perform experiments with the highly complex atmosphere ocean general circulation model COSMOS developed at the Max Planck Institute for Meteorology. On the other hand, we realise sensitivity experiments with the Earth system model of intermediate complexity Planet Simulator developed in the Department of Theoretical Meteorology at the University of Hamburg.

What can we do with models? Climate models allow the analysis of specific processes. Vegetation changes and their influence on the late Tertiary climate system have attracted relatively little interest so far as well as we still do not sufficiently understand other processes. The palaeoclimate modelling group E1.10 performs climate modelling sensitivity experiments to get a deeper insight into relevant climate processes. For instance, the climate response to the appearance of the Sahara at around the Miocene/Pliocene boundary can be analysed (fig. 3). The experiment demonstrates the global-scale climatic consequences, which are related to such a "loss of biodiversity".

Can we trust the models? In order to evaluate the performance of climate models for modern times, one can use observation data. Testing the reliability with observation data is a bit difficult for past climates, but nonetheless there exist methods to reconstruct palaeoclimatic conditions. Quantitative climate information can be derived from palaeobotanical evidences as well as from fossil mammals or other data (e.g., isotope data). The palaeoclimate modelling group E1.10 aims to combine results from palaeoclimate modelling with proxy data.