Study Offers Hope For Survival Of Island Nations As Sea Levels Rise

Bernama 23 Apr 14;

WELLINGTON, April 23 (Bernama) -- Some of the world's smallest nations might survive rising sea levels brought about by climate change but in different forms as their atoll islands grow and change, according to a New Zealand research.

Pacific island atolls might in fact be getting larger or remaining stable in their size as new gravel and sand is carried by waves from their coral reefs to shore, said Professor Paul Kench, head of the University of Auckland's School of Environment which is conducting the study.

Tiny island nations, such as Tuvalu and Kiribati, had been thought to be among the most vulnerable to rising sea levels but the study has shown very few islands shrinking in size, Kench told Xinhua news agency on Wednesday.

Researchers were building a dataset of changes over the past 50 years to 1,000 islands in the Pacific, and now had more than 500 examples.

Most of them, like Tuvalu, had either remained stable or grown, while some had been moving on their reef surfaces.

"We can't as yet determine whether some island groups are more susceptible or sensitive to change than others. However, this is something we believe we should be able to identify as the larger dataset develops," said Kench.

Some of the islands could hold relatively large populations, such as the more densely populated islands including South Tarawa on Kiribati, where at least 20,000 people lived, and Fongafale, Tuvalu, which was home to about 5,000 people.

"However, these are the urban capitals. There are many islands with small communities of 100 to 800 people. There are still many more islands with no one currently living on them," said the professor.

The least populated and least developed islands were likely to be more robust against rising sea levels than the bigger population centres.

"At some densely populated sites pollution may have reduced reef health and sediment production is diminished. The best mitigation measure that communities could engage in would be to maintain reef health," Kench said.

"It is possible that some islands may eventually have to be abandoned. However, this should not mean all islands in a nation will disappear.

"There are some large and uninhabited islands in most small nations that could be used to establish new settlements in the future. This infers that there may need to be some migration within a country," the professor said.

Vegetation could colonise newly accreted land very quickly, but the Pacific had many examples of people living on islands with a lack of vegetation.

However, urgent research is needed into whether water resources would change and communities would still be able to grow food crops such as taro.

More research is also needed into ocean acidification, another side-effect of climate change, and the impact this would have on the ability of reefs to generate fresh sand and gravel to build islands.

"It is possible that it might compromise the ability to generate fresh sand and gravel supplies from surrounding reefs," said Kench.

"However, others suggest that weaker skeletons of corals and other organisms might lead to a pulse of new sediment available for island building. There simply hasn't been sufficient research undertaken to resolve this question," he added.

--BERNAMA