A climate vulnerability and impact assessment model for complex urban systems

We present a hierarchical model developed for assessing the climate vulnerability and impact on the urban system to heat wave and pluvial flooding phenomena, which allows measuring the “urban performances” under extreme climate conditions by applying physical, environmental and socioeconomic indicators. The model is structured in five levels, from the knowledge of heterogeneous urban characteristics extracted from different sources to the vulnerability indicators; each level provides a synthesis of the information of the previous level. Moreover, given the complexity of the urban system, the model is based on the identification of three subsystems, in order to gradually synthesize information from one level to another. Each indicator, and the associated data and characteristics, are related to a specific subsystem, which represents technological/environmental (building, open spaces) or socioeconomic dimension (population). Finally, we assess the impacts related to a climate hazard scenario by evaluating the combination of the hazard with the exposure and the vulnerability of the subsystems with which the exposure interacts. We test our method on the study area of East Naples (Italy) by considering heat wave and pluvial flooding climate hazard scenarios; specific functions are performed in a GIS environment to implement the spatial analysis processes need to build the vulnerability indicators and impact scenarios. The results show that the distribution of vulnerability and impacts are related to the local urban context and to the hazard scenario considered. The proposed model can be applied to assess the benefits of adaptive solution design.