Due to their low-lying nature, coral reef island nations such as Maldives, Tuvalu, Kiribati, Marshall Islands (combined population > 1M) are widely acknowledged to be amongst the most vulnerable countries to climate change. It is widely assumed that the islands will become increasingly uninhabitable through this century, threatening their very existence.
However, such considerations ignore the ability of the islands to morphologically adjust to rising sea level and increased flooding frequency. Recent physical and numerical modelling carried out by the University of Plymouth has suggested, however, that coral reef islands can respond morphologically to rising sea levels by vertical accretion through overwash processes.
Island drowning is only the inevitable outcome of sea-level rise for islands where coastal structures, such as seawalls, have essentially cut-off the reef island from sediment supply from the reef platform and are preventing overwash from occurring, and/or where ecological processes have closed down and there are no new sediment supplies delivered to islands.