Urban Vulnerability: Requirements and Data Availability on the Global Scale

In this study, we compile and review the required and available data to do a global-scale urban vulnerability assessment for different hazards. Over the past decades, cities around the globe have rapidly increased in size. A larger concentration of people, assets, and economic activities in cities also mean that more elements are potentially located directly in harm’s way if a hazard occurs. The impacts of natural hazards are often expressed within the disaster risk framework, which describes disaster risk as a probabilistic function of hazard (i.e. the natural hazard event that potentially causes harm), exposure (i.e. those elements that are potentially in harm’s way), and vulnerability (i.e. the characteristics of the exposed elements that make them more or less susceptible to harm). Thus far, urban vulnerability has been investigated primarily on the local scale and is often led by data availability rather than suitability. To enable a more informed decision making process in vulnerability assessments, we aim to provide an overview of both relevant and available vulnerability indicators for six different hazards (pluvial flooding, coastal flooding, drought, earthquakes, heatwaves, and waterborne diseases). Our methodology is threefold: (1) An exhaustive overview of relevant urban vulnerability characteristics through a semi-systematic review of the peer-reviewed scientific literature (3000+ papers). Our focus is on empirically derived vulnerability characteristics, but we supplement this with information from modelled, theorized, adopted, or unknown derived sources. (2) An overview of available urban vulnerability indicators from supra-national urban datasets in a data review (100+ datasets). (3) A comparison of the relevant vulnerability information from the literature review with the available vulnerability data from the data review in order to explore what data acquisition activities are most needed in the context of urban vulnerability assessments. Lastly, we also discuss the outlook of a temporally dynamic (i.e. with values for different moments in time) vulnerability dataset with full global coverage in the urban context. The results can be used to inform researchers and urban decision makers tasked with disaster risk reduction on viable vulnerability indicators.