ASSESSING CLIMATE RISKS AND VULNERABILITY OF LOW-LYING CORAL ISLANDS

Coral reef islands face significant threats from climate change. They are typically less than few metres above present sea level and are composed of reef-derived sediments made from the shells and skeletons of deceased reef biota (Kench et al 2018; Dawson 2012). Coral islands and the living reefs that support them exist across a range of bio-physical conditions, and vulnerabilities to rising and warming seas, ocean acidification and increased storminess (Fellowes et al 2022; Sengupta et al 2023). In addition to the physical threats to coral island, threats that degrade or reduce the health of the living reef effect the supply of sediments to islands, may affect their structural stability by impacting sediment supply (Masselink et al 2020). Coral islands are dynamic coastal features with recent studies showing that many are growing while others are eroding (Kench et al 2018; Duvat et al 2019). It is largely unknown why some islands are resilient to change and other are not, and future stability of coral islands in the face of climate change is uncertain. This study proposes a risk classification for coral islands based on their exposures to bio-physical ocean and climate pressures, and their eco-morphometric attributes. This research is a step towards a greater understanding of risks and vulnerabilities to coral islands. Findings have direct implications for the 65 million people worldwide that live on low-lying coral islands, including Small Island Developing States (SIDS) and provides information needed to inform policy directions and management attention.