Abstract
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The Cocos (Keeling) Islands consist of the main atoll of Cocos, and the isolated North Keeling (Pulu Keeling) which is Australia’s smallest Commonwealth National Park. These rise from deep water, and the southern atoll consists of a near continuous rim with linear islands on the southern margin and a series of crescentic islands on the eastern side. The islands are anchored in their present location by an underlying conglomerate platform that was formed as a reef flat in mid Holocene when the sea level was higher than present. The islands themselves are largely sand, with restricted dune development on the most exposed oceanward shore. Their elevation is generally 3–4 m above modern sea level, and as the latest tide gauge, installed in 1992, shows evidence of sea-level rise, signs of inundation in the lowest-lying areas may be an omen of more frequent flooding in future (Woodroffe, 2008).