The climate of the 21st century is likely to be significantly different from that of the 20th because of anthropogenically-induced climate change. The Kyoto protocol and future initiatives, together with actions taken by the EU, are expected to reduce the impacts of the changes, but significant changes will still occur. These changes will be perceived by European citizens mostly through increases in some types of extreme weather. STARDEX aims to provide scenarios of expected changes in the frequency and intensity of extreme events (such as heavy precipitation and resultant flooding and high temperatures) which are likely to have an impact on human lives and activities and on the environment. Climate change scenarios, particularly those for extremes, are needed for all aspects of future design (e.g., water resources, agriculture, irrigation, storm and land drainage, road, railway and building design and other sectors such as tourism) where the weather and climate are key determinants of everyday life. In all these aspects there is a clear European-wide need for more reliable, high-resolution scenarios of extremes. STARDEX will not be making predictions, but providing information on the likely changes in extremes. If work of this kind is not undertaken, future designs will not be able to incorporate the latest information about changes in extreme climate in the future.
STARDEX will achieve its aims by a rigorous and systematic intercomparison of the three main downscaling methods (statistical, dynamical and statistical-dynamical) that are used to construct scenarios of extremes at the time and space scales where they are most needed. STARDEX will identify the more robust downscaling techniques and apply them to provide reliable and plausible future scenarios of temperature and precipitation-based extremes for selected European regions for the 2071-2100 timeframe. The extreme scenarios will incorporate three forms of uncertainty related to the specific downscaling method, different future emission paths and inter- and intra-model variability. To achieve these aims, STARDEX will develop standard observed and climate model data sets and a diagnostic software tool for calculating a standard set of extreme statistics across Europe. Two of the major climate models in Europe (HadCM3 and ECHAM4/OPYC) will be extensively validated, with the particular emphasis on extremes. The intercomparison of downscaling methods will take place using observed climate data from the second half of the 20th century. Finally, recent extremes across Europe will be analysed. What were their causes and impacts? Was anthropogenic climate change a factor? What can be learned from the recent past? The analysis of the recent past will bring together representatives from the re-insurance industry and the climate modelling and climate impact communities in an expert advisory panel.
The impacts of STARDEX will be improved methodologies for the development of scenarios of extremes, with recommendations as to which are best for different regions across Europe and for different variables. The various sectors listed above will be able to find off-the-shelf scenarios of extremes relevant to their business, incorporating all the various uncertainties. The scenarios will be used for many aspects of design (e.g., modification of dam design criteria, agricultural potential and alteration to insurance premiums) where extremes of weather are crucial determinants. The results will be made available through standard methods of scientific publications and reports, conferences and the World-wide Web.