A coastal exposure index for Ireland: relative hazard exposure and the protective role of coastal habitats.

UNLABELLED: The concurrent rise of global sea levels and coastal population growth is intensifying exposure to climate-driven hazards. In Ireland, where most major urban centres are on, or connected to the coast, the nature and severity of hazard impacts vary across diverse coastal landscapes. A spatially explicit assessment of coastal exposure is therefore critical for effective risk management and climate adaptation planning. This study presents a national-scale Coastal Exposure Index for Ireland, developed using the Coastal Vulnerability Model within the InVEST® software suite. The index integrates physical and climatic variables, including 30 years of wind and wave records, sea-level rise rates, and storm surge levels. Coastal habitats, including dunes, machair, saltmarsh and seagrasses, were directly represented to assess their potentially protective role. Exposure levels of coastal populations and cultural heritage sites were also evaluated. A critical appraisal of the InVEST® approach was undertaken, including a sensitivity analysis to assess how model modifications affect outcomes. Approximately 8575 km of coastline was assessed at an alongshore spacing of 250 m, with exposure reported on a relative scale. Results reveal that 38% of the coast benefits from potential exposure reduction provided by coastal habitats. The west coast exhibits the highest relative exposure values and contains the largest extent of "Very High Exposure" coastline. The model equally identifies exposure distribution along the east coast, with several eastern local authorities having some of the highest proportions of "Very High Exposure" coastline relative to their overall length. Coastal populations within each exposure category were estimated at multiple distances from the coast, revealing almost 10,000 residents in both Dublin City and Galway City live within 500 m of a "Very High Exposure" coastline. Cultural heritage sites were similarly mapped across categories and distances, with several exposure hotspots identified along the west and northwest coasts. By assessing the potentially protective role of coastal habitats, this study supports the integration of nature-based solutions in into coastal zone management and provides a national-scale screening assessment of relative exposure to guide evidence-based adaptation strategies. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at https://doi.org/10.1007/s11069-026-08361-w.