Awareness about the Relevance of Cascading Effects in Urban Critical Infrastructure Networks under Climate Change – a Participatory Impact Matrix Approach

Addressing climate change adaptation in urban areas is increasingly urgent. To achieve sustainable and climate-adapted fields of action requires fundamental transformations of supply chains and infrastructures such as transport and mobility, electricity and water supply, or telecommunication as well as an improved understanding of their interactions. Practical experiences show, that in general there is an increasing awareness about this, but for example emergency plans or crisis communication often falls short regarding the indirect impacts of climate change on potential infrastructural failures. Hence, there is also a growing need for applied research and systemic approaches to overcome the current prevailing isolated sectoral view of climate change impacts to gain a holistic understanding of the critical infrastructure networks. Against this background, the paper highlights the relevance of climate change impacts on critical infrastructures, infrastructure interdependencies and potential systemic cascading effects. The analysis uses a participatory approach that has been applied within a case-study for the metropolitan area of Hamburg, Germany. It is based on transdisciplinary research methods, connecting the realms of scientific knowledge about regional climate change with real-world experiences. A strong focus lies on the use of a specific impact matrix approach carried out with key stakeholders from different sectors to identify climate-related drivers causing the most severe failures and losses in the system – either directly in the same sector or indirectly due to breakdowns in other sectors. In sum, the case-study enables a first categorization of the role single key variables play in the infrastructure system. Furthermore, it introduces the topic of adaptation to climate change as a starting point for a better understanding and management of systemic risks in order to build and maintain resilient critical infrastructures and to make urban areas safe, resilient and sustainable