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‘Pacific low-lying islands are growing, not shrinking’

Australia: The latest research indicates that most of the Pacific’s low-lying islands are growing, not shrinking, according to The Australian. Researchers Paul Kench, at the University of Auckland, and Arthur Webb at the South Pacific Applied Geoscience Commission (SOPAC) in Fiji, in a paper published in the journal Global and Planetary Change, challenge the established belief that Pacific islands are rapidly eroding away.

Their examination through aerial photos and satellite imagery of the shape of 27 islands – the first quantitative analysis of such physical changes, they say – has found that, during the past 60 years, all but four have kept their size or have grown, in one case by 30 per cent.

“Local sea levels around the islands have been rising by an average of a mere 2mm a year during the past 50 years, although the rates of sea level rise are accelerating,” said Kench and Webb. Till now, they have discovered that seven islands have increased in size since the 1950s.

Further, Webb added, “The resilience of the islands is explained by their composition: chiefly of coral reef debris, in the case of low-lying atoll islands. Since the coral reefs are living, they provide a continuous source of material. Atolls are composed of once-living material, so you have a continual supply of sand and gravel to the island shores, [while] the surrounding reefs are healthy and productive. Two-thirds of atolls are growing inwards, towards the lagoons at their centre. And man-made structures such as causeways between islands may increase islands’ size by trapping sediments that would otherwise be washed back into the ocean.”

Kench added, “My data from the Maldives and observations in Tuvalu in the Pacific show that islands do have the capacity to grow vertically. This occurs in storm events when waves break and flow over the top of islands. Under such circumstances, sediment is transported from the reef and beach to the island surface. We have documented increases in island elevation of up to 0.3m in parts of the Maldives. This vertical building process is also evident in Tuvalu and other low-lying Pacific islands. An interesting outcome of the recent work is the fact that islands are in continual adjustment to changing boundary conditions. They have the ability to migrate on their reef platforms.”

They point out that when Cyclone Bebe hit Tuvalu in 1972 it deposited 140ha of debris on to the reef of the main island, increasing its size by 10 per cent, although they say that more frequent storms may eventually exhaust the supply of such debris.

The researchers said, “Island nations must place a high priority on resolving the precise styles and rates of change that will occur over the next century and reconsider the implications for adaptation – rather than for disintegration.”

On the other hand, The Australian mentioned the findings of Oxfam report as well. The report warned that, by 2050, 150 million people may be displaced globally because of climate change, half of them in the Asia-Pacific region: “The potential for climate displacement is especially a concern for low-lying atoll nations in Polynesia and Micronesia.”

Last August in Cairns, at a forum for leaders of the Pacific Islands, Climate Change Minister Penny Wong presented a video about the threat of inundation to Kiribati, most of whose atolls rise no more than 2.5m above sea level. Kiribati’s President Anote Tong has warned that the country’s entire population of 94,000 may need to be resettled as climate refugees.

Asked about the influence on policy of Kench and Webb’s research, Wong said, “The federal government believes climate change is real and so do our Pacific neighbours, who are already feeling the effects. We know Pacific island countries are likely to face significant challenges in the future, including the challenge of inundation.”

Yet in Kiribati the land area of the three most heavily populated islands – Betio, Bairiki and Nanikai – has increased by 30 per cent, 16.3 per cent and 12.5 per cent respectively, Kench and Webb reveal. They say much of this is because of reclamation and engineering.

Kevin Rudd told the summit of Pacific leaders: “Pacific island countries are among the least responsible for these issues [climate change] but they will bear the brunt of its impact.”

Consequently, Australia is spending USD 150 million over three years on a climate change programme in the Pacific. An AusAID spokeswoman said “This new research will not fundamentally alter Australia’s approach. Australia will continue to help Pacific island countries increase understanding of the impacts of climate change and respond at community, regional and national levels. This includes supporting cutting-edge research and funding priority adaptation activities based on the best available knowledge.”

Source: The Australian