Impact-based risk assessment of coastal infrastructure adaptation to climate change: a case study of hurricane risk in Nova Scotia, Canada

Coastal infrastructure faces escalating risks from climate change, including intensified tropical cyclones, wind, and storm surges, which threaten asset functionality and socio-economic activities. This study develops a probabilistic, spatiotemporal framework for quantifying physical and economic impacts on infrastructure and evaluating the cost-effectiveness of adaptation measures. The methodology integrates volunteered geographic information, sectoral damage functions, and hazard intensity to calculate asset-level expected annual damage (EAD) and changes in return period. A case study of Nova Scotia, Canada, demonstrates the framework under current and future climate scenarios (RCP 4.5 and RCP 8.5), including projected sea-level rise, for three infrastructure types: buildings, medium voltage power lines, and primary roads. Hazard simulations indicate that both wind and surge impacts intensify under future scenarios, with expected building damage increasing from US$ 150 million under current conditions to US$ 330 million under RCP 8.5. Adaptation measures, including sea marshes and sea dikes, are evaluated for cost-effectiveness, showing EAD reductions of up to 69% (benefit-to-cost ratio 2.14) and 84% (ratio 1.13), respectively, under severe climate conditions. Local-scale assessment using Bayesian networks expands the method for spatially explicit estimates of vulnerability and damage, supporting targeted prioritization of assets and adaptation strategies. The modelling framework is implemented using the open-source CLIMADA platform, enabling reproducible probabilistic hazard, impact, and adaptation analysis. The framework enables decision-makers to assess climate risk quantitatively, integrate economic valuation, and evaluate adaptation options at the asset level, offering a flexible, practical approach for spatiotemporal vulnerability assessment, and infrastructure resilience strategies against climate extremes. • Developed impact-based method for coastal infrastructure climate risk assessment • Coupled hazard intensity with asset vulnerability for spatial risk mapping • Quantified expected annual damage under present and future climate scenarios • Evaluated cost-effectiveness of green and grey adaptation measures • Demonstrated decision-support value using a Nova Scotia hurricane case study