A review of the vulnerability of low-lying reef island landscapes to climate change and ways forward for sustainable management
David M. Kennedy
Abstract
Low-lying small island states whose existence is a product of sediment production from their surrounding reefs are highly vulnerable landscapes to climate change. This vulnerability derives from their low elevation and their evolutionary reliance on growth on the surrounding reef for the creation of materials from which land can form above the sea. They are also exposed to a range of climatic boundary conditions (e.g. tropical cyclones) which vary in intensity with distance from the equator. The diversity of energy environments, evolutionary history, sea level history and local ecology means reef-islands have unique characteristics (sediments and topography) that vary both within individual atolls as well as along island chains. It is also clear the majority of islands today have continued to accrete in the last century. Such development has led to suggestions that islands may be less vulnerable to sea level rise than suggested by their elevation alone. Vulnerability of an island system, however, does not equate to sustainable human occupation. In addition, projected rates of sea level rise will exceed that experienced in the last century. For understanding the stability of reef-island systems it is therefore imperative for managers to be fully cognisant of the principle drivers of island evolution, their modern dynamics and future sea level trends. In this paper, a review is undertaken of the principle physical elements, and methods to investigate them, that are a priority for quantifying when conducting an integrated assessment of the physical landscape of small island states. Advances in remotely operated vehicles combined with simple sedimentological techniques (e.g. visual grain identification) mean it is now possible for local managers to collect key information necessary for protecting their islands and, if needed, the data can be used for numerical models of island change.