Sunday, June 6, 2010

Low-lying Pacific islands 'growing not sinking' as sea levels rise

At five metres above sea level, Tuvalu has one of the lowest maximum elevations in the world, making it extremely vulnerable to storms and changes in sea level.

From : DailyMail

Many low-lying islands in the Pacific are growing in size to counter the effects of rising sea levels, according to new research.

Scientists have feared that many of the small islands throughout the South Pacific will eventually disappear under rising sea levels caused by climate change.
But two researchers who measured 27 islands where local sea levels have risen 4.8 inches over the past 60 years, found just four had diminished in size.

The study found that the coral islands are able to respond to changes in weather patterns and climate, with coral debris eroded from encircling reefs pushed up onto the islands' coasts by winds and waves.
Professor Paul Kench of Auckland University's environment school said that the study shows the islands are coping with sea-level change, with higher waves and water depth supplying sand and gravel from coral reefs.

Professor Kench said: 'It has been thought that as the sea level goes up, islands will sit there and drown. But they won't. The sea level will go up and the island will start responding.'
'They're not all growing, they're changing. They've always changed ... but the consistency (with which) some of them have grown is a little surprising,' said.

Tuvalu, a coral island group that climate change campaigners have repeatedly predicted will be drowned by rising seas, has its highest point just 14 feet above sea level.
The research, which appeared in this week's New Scientist, found that seven of Tuvalu's nine islands had grown by more than 3 percent on average over the past 60 years.
In 1972, Cyclone Bebe dumped 346 acres of sediment on the eastern reef of Tuvalu, increasing the area of Funafuti, the main island, by 10 percent.

Another island, Funamanu, gained nearly 30 percent of its previous area.
On World Environment Day in 2008, Kiribati President Anote Tong warned parts of his island nation were already being submerged, forcing some of Kiribati's 94,000 people living in shoreline village communities to be relocated from century-old sites.
Worst case scenarios showed Kiribati would disappear into the sea within a century, he said at the time.

Professor Kench added: 'In other words, they (the islands) are slowly moving ... migrating across their reef platforms.'
'As the sea-level conditions and wave conditions are changing, the islands are adjusting to that.'
But he warned an accelerated rate of sea-level rise could be 'the critical environmental threat to the small island nations,' with 'a very rapid rate of island destruction' possible from a water depth beyond a certain threshold. That threshold currently is unknown.

Australian sea level oceanographer John Hunter said the findings 'are good news and not a surprise.'
'Coral islands can keep up with some sea-level rise, but (there's also) ocean warming ... and ocean acidification ... that are certainly problematic for the corals.
'Sea-level rise can actually make the islands grow - as it apparently is doing,' said Hunter.

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