Start Date: March 29, 2017 - 04:15 PM
End Date: March 29, 2017 - 05:15 PM
Abstract: There is ample archaeological and geological evidence that the Saharan and Arabian deserts were greener than today during the so-called early and mid-Holocene several thousand years ago. Palaeoclimatic modelling indicates that this greening was triggered by changes in insolation due to steady variations in the Earth orbit, and it was likely amplified by feedbacks between atmosphere, ocean and land. Some palaeo records reveal changes in desert conditions (Saharan dust deposition, vegetation composition) which occurred some 5000 years ago at a pace much faster than the change in climate forcing. Theoretical studies actually predicted that an abrupt expansion of deserts should have happened some 5000 years ago. More complex models, however, suggest that the diversity of plants can affect the strength of feedback: regions rich in plant diversity may stabilize the system leading to more gradual transitions. The future of the Saharan and Arabian deserts strongly depends on how climate will evolve in the future. With greenhouse-gas induced climate warming some greening could occur already in this century.
Bio: Professor of Meteorology at the Meteorological Institute at the University Hamburg and Director at the Max Planck Institute for Meteorology, Hamburg (Germany). Claussen’s scientific expertise is meteorology and climate system modelling. He is interested in understanding feedback processes in the climate system in past, present and future climate with a focus on vegetation – climate interaction. He was one of the first to simulate dynamic vegetation patterns and atmospheric circulation.
Claussen has been member several national and international committees, such as the Scientific Committee of the International Geosphere – Biosphere Program. He has received the Milutin Milankovitch Medal of the European Geosciences Union and the Johannes Georgi Award of the GeoUnion / Alfred Wegener Foundation. Claussen is member of several academies including the German National Academy of Sciences, Leopoldina, and the Academia Europaea.