Islands may be resilient to rising sea
Research suggests submersion a misconception
Scientists have created a replica of a coral reef island to reveal what a metre of sea level rise would mean for communities in low-lying spots. Remote island nations in the Pacific and Indian Oceans have for many years been considered extremely vulnerable to the effects of climate change and, in particular, rising sea levels.
Many have gone so far as to predict they could even be completely submerged within the next century as sea level rises, forcing their populations to flee and become among the first climate refugees.
However, new research by the University of Auckland and University of Plymouth is seeking to demonstrate that islands formed on coral reefs are more resilient than has perhaps been suggested in the past.
It is seeking to support previous field studies conducted by scientists in Auckland, which have suggested that rather than being submerged by sea water, the islands may adapt with the sand and gravel around their coastlines shifting to form a new and higher barrier against the rising sea level.
Coral reef islands are low-lying islands that sit on top of coral reef surfaces and provide the only habitable land in mid-ocean atolls.
Professor Paul Kench, head of the University of Auckland’s School of Environment, has spent more than two decades monitoring environmental changes to islands and atolls in the Pacific and Indian oceans.
“Over recent decades, it has become a commonly held belief that nations such as the Maldives, Chagos or Marshall islands are simply going to vanish as sea levels rise,” he said.
“But our research would suggest it is in fact a commonly held misconception, and what we actually believe will happen is that as sand and gravel shift it will form a natural barrier against the sea.
“This is the first time we have been able to test that theory in a laboratory facility, and by replicating the conditions these remote nations face we hope to demonstrate the resilience of the islands but also enable them to appropriately prepare for the future challenges they may face.”
Uncertainty around ice melt projections has made it difficult for scientists to put a precise figure on how much sea level rise can be expected to affect island communities under climate change, but Kench said one metre was a good base level to work from.
The research collaboration was supported with funding by the Royal Society of New Zealand Catalyst Fund, and a 1:50 scale replica of a coral reef island in Tuvalu — around 3000km north of New Zealand — which has been constructed in the coastal basin of Plymouth’s Coast laboratory.
The model will be subjected to rising sea level and increased wave activity, with sensors recording data which will be correlated against previous field measurements taken over the past two decades and also with a numerical model.
The University of Plymouth’s Professor Gerd Masselink said work already carried out has shown that these islands did move and change, but the direction of the global debate was not allowing their populations to adapt and plan for the future using this knowledge and understanding.