Change in the frequency of extreme events as the indicator of climatic change in the Holocene (in fluvial systems)

The transformation of natural systems of climatic origin in the Holocene may be realised by a change in the type of extreme events, or by a change in their frequency. or by both. The rapid v arming at the Younger Dryas-Preboreal transition exemplifies a parallel drop in frequency and a change in the type of events. Several wetter phases of the Holocene are characterised by rises in frequency of various types of extreme rainfalls, The fragmentary records of events in the fluvial and slope systems coincide with smoothed variations in stable ecosystems and shifts of ecotonal zones (such as tree line and lake levels). (C) 2002 Elsevier Science Ltd and INQUA. All rights reserved.