Higher Risk of wet Winters in Europe due to Climate Change ?

Exchanges Risk (21 st C) / Risk (20 th C) Figure 1 from paper 'Quantifying risk in a changing climate': by T. Palmer and J. Räisänen: Upper left: the probability of a wet winter defined from the control CMIP2 ensemble with 20th century levels of CO 2 and based on the event E: DJF rainfall greater than the mean plus one standard deviation. Upper right: the probability of E but using data from the ensemble with transient increase in CO 2 , and calculated around the time of CO 2 doubling (years 61-80 from present). Bottom: the ratio of the middle to top panel values, giving the change in the risk of a wet winter, arising from man's impact on climate. The paper appears on page 3. The work of the Intergovernmental Panel on Climate Change is underpinned by CLIVAR's research on Detection and Attribution of Climate Change. This special issue focuses on these topics. Editorial This year, the Third Assessment Report (TAR) " Climate Change 2001 " of the Intergovernmental Panel on Climate Change (IPCC) (http://www.ipcc.ch) has been published. Its three volumes deal with the " Scientific Basis " , " Impacts, Adaptation and Vulnerability " and " Mitigation ". (These are supplemented by more widely distributed " Summaries for Policymakers "). The TAR represents an enormous effort by many scientists in collating, reviewing and presenting the present state of our knowledge of the climate system, of the known and potential human influences and of the likely global and regional impacts of climate change. When CLIVAR was originally conceived it was struc-tured (for the sake of convenience) around three timescales-Seasonal to Interannual (dealing with phenomena such as ENSO and Monsoons), Decadal to Centennial and An-thropogenic Climate Change. The work of IPCC is clearly focused on Anthropogenic Change issues but, because of the short (typically only 100 years) instrumental record available to us, understanding the inherent variability of the climate system even on interannual scales (Do ENSO events introduce regional and global biasses?) is crucial. Thus all of CLIVAR's observational and modelling activities underpin the IPCC process. We have therefore taken this opportunity to include in this issue of CLIVAR Exchanges some articles that are closely related to the IPCC activities. We had a very good response for our call for papers and include articles on various facets of the problem ranging from the investigation of anthropogenic, influences on natural …