Downscaling from Whole-Island to an Island-Coast Assessment of Coastal Landform Susceptibility to Metocean Change in the Pacific Ocean

Assessment of Pacific island vulnerability to changing climate and ocean conditions was undertaken at two scales, demonstrating a technique for vulnerability downscaling and establishing the suitability of coastal landform information to application at country or island scale. The approach acknowledges the transition of physical characteristics influencing coastal vulnerability with scale. At the whole-island scale, the geologic and morphologic structure describes likely susceptibility to change. At a more detailed scale, considering landforms comprising the coastal fringe of each island, physical characteristics describe relative coastal instability. The assessment demonstrated linkage between the two scales, with a shift from predominantly static geologic to more dynamic geomorphic data. The analyses explore a technique using remotely sensed data covering the Pacific Islands and may be applicable across a range of planning and management scales from broad, regional description of different island types to single island coasts. Although this carries potential problems of misinterpretation, it also offers opportunity for tighter definition of criteria at a country or island scale where authorities could verify the interpretations through direct field observation.