The reduced habitability of small islands is an overarching significant risk caused by a combination of several key risks facing most small islands even under a global temperature scenario of 1.5°C . These are loss of marine and coastal biodiversity and ecosystem services; submergence of reef islands; loss of terrestrial biodiversity and ecosystem services; water insecurity; destruction of settlements and infrastructure; degradation of health and well-being; economic decline and livelihood failure); and loss of cultural resources and heritage. Climate-related ocean changes, including those for slow-onset events, and changes in extreme events are projected to cause and/or amplify Keys Risks in most small islands. Identification of key risks facilitates the selection of optimal context- specific adaptation options. Moreover, it can distil the benefits and/or disadvantages and long-term implications of choosing such options  .
IPCC
Climate Change 2022: Impacts, Adaptation and Vulnerability
IPCC Report