Social vulnerability to health impacts of climate change in Australia: understanding drivers and inequalities

Background: A limited ability to identify social vulnerability and community resilience at local scales has been recognised as a critical barrier to both climate adaptation and health risk assessment and planning. This study aims to assess multi-domain social vulnerability to the health impacts of climate change across communities in Australia using a system based approach, quantify contributions across intervention levers, and identify key drivers of health inequalities. Methods: Informed by a scoping review and the WHO Social Determinants of Health Equity framework, we compiled area-level data from multiple sources on 57 social vulnerability indicators, subsumed under 32 subdomains and 7 domains (demographic profile, economic security, residential environment, infrastructure and services, community context, population health, and governance and policies). These indicators were used to construct a Social Vulnerability Index for the Health Impact of Climate Change (SVI-HICC) and scores in each domain. We examined the association between the SVI-HICC and health outcomes related to extreme weather and climate events, evaluated its performance relative to alternative social indices, and identified main contributors to social vulnerability using dominance analysis. Findings: Spatial mapping revealed geographic variation in the composition of social vulnerabilities across domains and subdomains. High social vulnerability was more common in regional and remote areas, primarily associated with demographic and economic disadvantages, while pockets of high social vulnerability were also observed in urban areas, largely attributable to residential environment and community context. People in highly vulnerable areas experienced greater losses in mental, emotional, social, physical, and general health from weather and climate extreme events. Community context (driven by social support and networks), residential environment (driven by dwelling condition), and infrastructure and services (driven by communication access) were identified as the strongest contributors to social vulnerability. Conclusion: An area-level assessment of social vulnerability makes visible how social and structural determinants contribute to health inequities in climate change. Such insights can inform climate adaptation policies that are equity-oriented and context-sensitive.