Letters to Nature

Nature 425, 166-169 (11 September 2003) | doi:10.1038/nature01928; Received 16 May 2003; Accepted 16 July 2003

No upward trends in the occurrence of extreme floods in central Europe

Manfred Mudelsee1,3, Michael Börngen1, Gerd Tetzlaff1 & Uwe Grünewald2

  1. Institute of Meteorology, University of Leipzig, Stephanstrasse 3, 04103 Leipzig, Germany
  2. Institute of Hydrology, Technical University Cottbus, PF 101344, 03103 Cottbus, Germany
  3. Present address: Department of Earth Sciences; Boston University, 685 Commonwealth Avenue, Boston, Massachusetts 02215, USA

Correspondence to: Manfred Mudelsee1,3 Email: mudelsee@uni-leipzig.de

Extreme river floods have been a substantial natural hazard in Europe over the past centuries1, and radiative effects of recent anthropogenic changes in atmospheric composition are expected to cause climate changes, especially enhancement of the hydrological cycle2, leading to an increased flood risk3, 4. For the past few decades, however, observations from Europe1, 5, 6, 7 do not show a clear increase in flood occurrence rate. Here we present longer-term records of winter and summer floods in two of the largest rivers in central Europe, the Elbe and Oder rivers. For the past 80 to 150 yr, we find a decrease in winter flood occurrence in both rivers, while summer floods show no trend, consistent with trends in extreme precipitation occurrence. The reduction in winter flood occurrence can partly be attributed to fewer events of strong freezing—following such events, breaking river ice at the end of the winter may function as a water barrier and enhance floods severely. Additionally, we detect significant long-term changes in flood occurrence rates in the sixteenth to nineteenth centuries, and conclude that reductions in river length, construction of reservoirs and deforestation have had minor effects on flood frequency.