Tuesday, November 16, 2010

Whoops: Global Warming Decreased Floods

From the annals of The Settled Science, a peer-reviewed paper published today in Water Resources Research shows that flooding over the past 450 years in Germany was highest during "colder periods of the Little Ice Age when solar activity was reduced." On the other hand, the IPCC claims the sun has nothing to do with climate change and that 'man-made' global warming will increase floods worldwide. This paper corroborates other research showing floods are 10 times more likely during global cooling periods vs. global warming periods. 


A 450 year record of spring-summer flood layers in annually laminated sediments from Lake Ammersee (southern Germany)

Authors: Markus Czymzik, Peter Dulski, Birgit Plessen, Ulrich von Grafenstein, Rudolf Naumann, Achim Brauer

Abstract: A 450 year spring-summer flood layer time series at seasonal resolution has been established from the varved sediment record of Lake Ammersee (southern Germany), applying a novel methodological approach. The main results are (1) the attainment of a precise chronology by microscopic varve counting, (2) the identification of detrital layers representing flood-triggered fluxes of catchment material into the lake, and (3) the recognition of the seasonality of these flood layers from their microstratigraphic position within a varve. Tracing flood layers in a proximal and a distal core and correlating them by application of the precise chronology provided information on the depositional processes. Comparing the seasonal flood layer record with daily runoff data of the inflowing River Ammer for the period from 1926 to 1999 allowed the definition of an approximate threshold in flood magnitude above which the formation of flood layers becomes very likely. Moreover, it was possible for the first time to estimate the “completeness” of the flood layer time series and to recognize that mainly floods in spring and summer, representing the main flood seasons in this region, are well preserved in the sediment archive. Their frequency distribution over the entire 450 year time series is not stationary but reveals maxima for colder periods of the Little Ice Age when solar activity was reduced. The observed spring-summer flood layer frequency further shows trends similar to those of the occurrence of flood-prone weather regimes since A.D. 1881, probably suggesting a causal link between solar variability and changes in midlatitude atmospheric circulation patterns.

Received 7 July 2009; accepted 9 August 2010; published 17 November 2010.

Related: Recent worldwide droughts have also been mild compared to other periods over the past 500 years:

1 comment:

  1. More clouds = more cooling and more rain. Whoda thunk?