Aug. 4, 2008 Researchers in Germany, Switzerland, and the United States have shown, for the first time, that an extremely fast climate change occurred in Western Europe. This took place long before human-made changes in the atmosphere, and is causatively associated with a sudden change in the wind systems.
The research, which appears in the journal Nature Geoscience, was conducted by geoscientists Achim Brauer, Peter Dulski and Jörg Negendank (emeritus Professor) from the GFZ German Research Centre for Geosciences, Gerald Haug from the DFG-Leibniz Center for Surface Processes and Climate Studies at the University of Potsdam and the ETH in Zurich, and Daniel Sigman from Princeton University.
The proof of an extreme cooling within a short number of years 12,700 years ago was attained in sediments of the volcanic lake Meerfelder Maar in the Eifel region of Germany. The seasonally layered deposits allow to precisely determine the rate of climate change. With a novel combination of microscopic research studies and modern geochemical scanner procedures, the scientists were able to successfully reconstruct the climatic conditions even for individual seasons. In particular, the changes in the wind force and direction during the winter half-year caused the climate to topple over into a completely different mode within one year after a short instable phase of a few decades.
Up to now, it was assumed that the attenuation of the Gulf Stream alone was responsible for the strong cooling in Western Europe.
The examined lake deposits show, however, that the atmospheric circulation, probably in connection with the spreading of sea-ice, most likely played a very important role. At the same time, these new results show that the climate system is still not well understood, and that especially the mechanisms of short-term change and the time of occurrence still hold many puzzles. Micro-layered lake deposits represent particularly suitable geological archives, with which scientists want to track down climate change.
Scientists from the Helmholtz Centre Potsdam – German Research Centre for Geosciences (GFZ) and other institutions are in search of such archives worldwide, with the hope of obtaining area-wide information on the dynamics of climate and possible regional variations in the future.
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- Brauer et al. An abrupt wind shift in western Europe at the onset of the Younger Dryas cold period. Nature Geoscience, 2008; 1 (8): 520 DOI: 10.1038/ngeo263
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