Development and application of a social vulnerability index at the local scale

Social vulnerability to climate change is increasingly being acknowledged, and proposals to measure and manage it are emerging. Building upon this work, this research proposes an approach to social vulnerability assessment using an empirical Social Vulnerability Index (SVI). Three principal novel developments of the study can be described, including: new practical definitions of SVI components; a new mechanism to aggregate and account for causal relationships among SVI components; and use of innovative community-based methods for data collection in developing the SVI.

Building from existing studies of and models for SVIs, the research proposes new definitions for three key components, exposure, sensitivity and adaptive capacity. This responds to a lack of clarification of SVI components in work to date. The new definitions not only concretize classical concepts of seminal work in this area but also express quantifiable aspects of SVI components. In addition, a new algorithm established to produce an aggregated SVI in this research overcomes some inherent limitations of existing approaches. The proposed SVI formula is a simple equation and can be easily computed. This helps address existing complexity and vagueness in SVI calculation. It also reflects causal relationships among the SVI components that are lacking in previous studies. Furthermore, the process of SVI calculation in this research avoids the step of data standardization which is common in recent research. This improvement overcomes the inherent limitation of data standardization - namely, that the calculated SVI may not be compatible with future studies.

To operationalise this index, a combination of qualitative and quantitative methods are proposed and tested, based on engagement with local environmental professionals and community members in a case study location, Quy Nhon city in Binh Dinh Province on the central coast of Vietnam. SVI factors selection using expert judgement to capture local stakeholders’ perspectives is shown to be possible through qualitative methods, including a Delphi survey, key informants interviews and two focus group discussions. Compared to data-driven and theory-driven approaches, using local opinions helps reveal more explicit understandings of issues associated with social vulnerability to climate change locally, and to develop locally appropriate SVI factors. In the quantitative stage, a primary dataset approach is underpinned by application of a specifically-designed household survey questionnaire with participation of 1,029 households in Quy Nhon city. The calculation of SVI at the fine-grained local scale provides high resolution in vulnerability assessment, and also obviates the need for secondary data, which may be unavailable or problematic, particularly at the local scale in developing countries.

The calculated SVI in this study is then used to propose adaptive strategies and specific actions for responding to climate change in Quy Nhon city. The research reveals inherent limitations of existing SVIs but also indicates the potential for their use in assessing social vulnerability and making decisions associated with responding to climate change at the local scale.