Effects of cumulative exposures to climate-related disasters on social capital

Background: Social capital is recognised as a key resource that supports disaster recovery. Yet, as climate change drives more frequent and overlapping disasters worldwide, our understanding of how consecutive or compounding events affect social capital – its access and capacity to aid community recovery – remains limited. This study investigated how multiple disasters affected social capital, what explained variations in these effects across communities, and their role in shaping mental, social, and general health over time. Methods: Using population-based longitudinal data from 2009 to 2019 in Australia, people who experienced home damage from at least one disaster (flood, bushfire, or cyclone) were tracked from pre-disaster to post-disaster years after the first and repeated disasters, in comparison to unexposed baselines. The effects of cumulative disaster exposures on different types of social capital (bonding, bridging, and linking) were assessed using a panel event study design with linear models with multiway fixed effects and clustering. Trajectory heterogeneity was examined to identify factors contributing to losses and gains in social capital over time. The capacity of social capital to support mental, social, and general health across multiple disasters was determined. Results: Climate-related disasters negatively affected bonding social capital, which declined further with repeated disasters. The effect of repeated disasters was especially pronounced for the youth cohorts, renters, and areas with socioeconomic disadvantages. Post-disaster trajectories in mental, social, and general health were significantly shaped by access to bonding social capital. In contrast, there was evidence of a trend toward increased bridging and linking social capital in response to repeated exposures to climate-related disasters. Conclusion: Further increases in disaster exposure linked to climate change may undermine close social ties, eroding protective buffers of bonding social capital and limiting the ability of populations to draw upon mutual aid as a coping strategy. This underscores the need for interventions that sustain and strengthen social capital in the context of repeated disaster exposures.