Cyclic climate fluctuations during the last interglacial in central Europe
- 1Institute of Geology and Paleontology, Johann Wolfgang Goethe University, 60054 Frankfurt, Germany, and Lamont-Doherty Earth Observatory, Columbia University, Palisades, New York 10964, USA
- 2Institut für Geowissenschaften, Universität Tübingen, D-72076 Tübingen, Germany
- 3Leibniz Institute for Applied Geoscience (GGA), D-30655 Hannover, Germany
- 4Institute of Geology and Paleontology, Johann Wolfgang Goethe University, 60054 Frankfurt, Germany
- 5Lamont-Doherty Earth Observatory, Columbia University, Palisades, New York 10964, USA
Abstract
Differentiating natural climate change from anthropogenic forcing is a major challenge in the prediction of future climates. In this context, the investigation of interglacials provides valuable information on natural climate variability during periods that resemble the present. This paper shows that natural cyclic changes in winter climates affected central European environments during the last interglacial, i.e., the Eemian, 126–110 ka. As a result of the extraordinarily high counting sums performed at Eemian pollen samples, it was possible to reveal a robust presence–absence pattern of the insect-pollinated, and therefore in the pollen rain underrepresented, taxon Hedera. This plant is known to require the influence of oceanic winter climates, i.e., moist and mild, in northwest and central Europe. By analogy with recent findings from the North Atlantic's Holocene interglacial, the trigger of the Eemian climate variability may have been changes in solar activity, possibly amplified by changes in North Atlantic ocean currents and/or in the North Atlantic Oscillation. Our findings suggest natural cyclic changes to be a persistent feature of interglacial climates.
Footnotes
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- Accepted 4 February 2005.
- Received 28 October 2004.
- Revision received 27 January 2005.
- The Geological Society of America, Inc.
