Dynamic risk scenarios for single and multi-hazards in the Global South: Nairobi, Istanbul and Kathmandu

Single natural hazards, multi-hazards, and anthropogenic processes all contribute to dynamic risk due to the changing nature of the hazard, exposure, and vulnerability over time. Here we discuss the development of dynamic risk scenarios for single and multi-hazards, including multi-hazard interrelationships, in the context of three urban areas, Istanbul, Kathmandu, and Nairobi, all foci of the UK GCRF funded “Tomorrow’s Cities” Research Hub. We first do systematic overviews of multiple sources of evidence (academic and grey literature, online media, social media) to produce a profile of single hazards and multi-hazard interrelationships for each urban area, from which we produce dynamic risk scenarios. Then, we further developed dynamic risk scenarios through co-production with relevant local hazard stakeholders in facilitated workshops and semi-structured interviews in Nairobi and Istanbul. The dynamic risk scenarios include multiple types of single hazards, three different hazard interrelationships (i.e., triggering, increased probability, and compound hazards) and anthropogenic processes. These dynamic risk scenarios are relevant for short-term considerations (e.g., days or weeks, such as an earthquake triggering landslides and blocking rivers) or longer-term (such as climate change influencing the hazard, or anthropogenic processes of urban growth influence the hazard, exposure, and vulnerability). Examples of challenges identified by stakeholders include governance-related issues, such as siloed approaches to hazards which are often single-hazard focused, lack of enforcement of regulations, translation of planning to implementation, centralised policy-making, needs beyond electoral cycles, lack of financial and human resources, and disconnect between scientific and policy-making communities. Other challenges stakeholders identified include a lack of existing data and research in their region on multi-hazard interrelationships, anthropogenic processes and risk, and other components that make up dynamic risk scenarios. Opportunities identified by stakeholders include increased awareness of the factors that might influence risk dynamically in their urban region and integration of these factors into existing urban regeneration project planning. As identified by local stakeholders, these scenarios have a vast array of potential benefits for disaster risk management in their cities, especially in terms of enhanced preparedness and risk-informed planning.