The SUDPLAN project aims at developing an easy-to-use web-based planning, prediction, decision support and training tool, for the use in an urban context, based on a what-if scenario execution environment, which will help to assure population's health, comfort, safety and life quality as well as sustainability of investments in utilities and infrastructures within a changing climate.This tool is based on an innovative and visionary capacity to link, in an ad-hoc fashion, existing environmental simulation models, information and sensor infrastructures, spatial data infrastructures and climatic scenario information in a service-oriented approach, as part of the Single Information Space in Europe for the Environment (SISE). It will provide end users with cutting edge highly interactive 3D/4D visualization, including visualisation on real 3D hardware.The tool includes the SUDPLAN Scenario Management System with three so-called Common Services. The latter will allow downscaling of regional climate change model results to a spatial and temporal scale useful for urban planning in whatever European city. SUDPLAN Common Services include gridded information on present and future extreme rainfall, temperature, river runoff and air pollution.Vital consequences of climate change are considered in 4 carefully selected urban pilot applications located in Austria, the Czech Republic, Germany and Sweden. The SUDPLAN Scenario Management System with Common Services information will here be used to execute and visualize results from local high resolution models and sensor systems, covering diverse applications such as a) extreme rainfall episodes causing problems with uncontrollable, extremely localized runoff and critical loads to drainage and sewage systems, b) extreme river discharges or droughts c) hazardous air pollution and high ambient temperature episodes causing health risks.Through innovative ICT, SUDPLAN contributes to SISE, provides new perspectives for a distributed service market, reinforces European leadership in the research area and fosters the capacity to cope with climate change impacts in urban environments.