Vulnerability to sea level rise: A novel local-scale indicator-based assessment methodology and application to eight beaches in Shoalhaven, Australia

Abstract

Vulnerability of a socio-ecological system to one or more climatic hazards depends on climatic, geophysical, socio-economic and institutional factors. In addition, vulnerability is a scale- and place-dependent concept. While decision-making on adaptation is often made by local government, only a small number of local-scale assessments have been conducted. When indicators are used, global utility functions based on additive or multiplicative aggregation implicitly assume complete compensation between indicators, implying that one source of vulnerability (e.g., proximity to the sea) can always be compensated for by an advantage in another source (e.g., strong social or economic capital) when evidence shows that this is not always the case.

This paper presents an indicator-based assessment of vulnerability of eight beaches in Shoalhaven, New South Wales, that are especially exposed to sea level rise. Its goal is twofold. First, it illustrates how indicator-based vulnerability assessments can be applied at a local scale – and not just sectoral, regional and national scales – with the aim of informing local government adaptation planning and resource allocation. In the process, models operationalising the concepts of exposure, sensitivity and adaptive capacity are developed for two valued attributes identified through discussions with the local council, namely the well-being of beach residents and the well-being of users of infrastructure systems located at the beaches.

Second, the paper studies, for the first time, the way outranking procedures can be applied in real-life vulnerability assessments as a form of data aggregation that better reflects the non-compensatory nature of many vulnerability indicators. The strengths and weaknesses of the outranking approach are discussed, especially the extent to which the concepts of preference, indifference and dominance thresholds can be conveyed to, and their values elicited from, stakeholders.