Components of urban climate analyses for the development of planning recommendation maps

Due to their high density and sealing, cities are vulnerable to more frequently occurring extreme weather events such as heat, heavy rainfall and storms. Urban planning needs to respond to these climate risks. Urban climate analysis maps are used to assess climate-related hazards. Subsequently, planning recommendation maps aim to inform urban planning processes and to derive effective measures for climate change adaptation planning. Taking the IPCC risk concept as a methodological framework, this paper assesses whether and how all three components of this concept - hazards, exposure and vulnerabilities - are considered in existing urban climate analyses and planning recommendation maps based on a comparison of 12 urban climate analyses from Switzerland, Germany and Austria. This comparative analysis highlights difficulties in the practical delineation of the components hazard, exposure and vulnerability in order to assess the risk of climate impacts on cities. The informativeness of planning recommendation maps depends on the depth of the analyses of the components and subsequently affects the quality of derived planning measures for urban climate adaptation and mitigation planning. The results confirm that there are basically two methodological approaches: those of climatopes and those of urban climate models. Increasingly, there are also mixed forms that combine the possibilities of both variants. Many additional analyses or components are needed to carry out a comprehensive risk analysis, to identify particularly affected areas and thus to provide spatially explicit indications for measures. We conclude from our comparison that urban climatic analyses must therefore include four components to enable spatial climate change adaptation: (1) urban climatic analysis related to the hazard component, (2) in depth social and spatial analysis related to exposure and vulnerability components, (3) adaptation options and thus (4) planning recommendations and planning recommendation maps as "guidance to reduce the risk". To improve these analyses and provide a better basis for decision making and planning a (international) standardisation is recommended. A joint analysis of climate scenarios as well as socio-demographic and spatial developments can support a better analysis of (future) risks for cities. The effectiveness and implementation could be promoted if the analyses are linked to the cities' "regular" planning instruments and the statutory planning instruments.