Battling a Rising Tide

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Naseer explains this debate is not just purely academic, and such knowledge may help the Maldives to make better informed decisions about the management of its reefs. "The Maldives are being threatened by the rise in sea level due to global warming and increasingly violent weather," he says. As global warming seems to be more of an obvious reality, Maldivian scientists and government officials alike are concerned about the effects of rising sea levels. Since the Maldives islands are on average 5 feet (1.5 meters) above sea level, even a sea level rise of half a meter would cause severe problems for the more than 250,000 residents living there. Not only would flooding be a problem, but the seas may rise so quickly that they could erode the coral islands. If the reefs supporting an island fail to keep up with the rising waters, the island itself will inevitably disintegrate. To date the only recourse the Maldivians have against this potential catastrophe are concrete retainer walls. While such walls have effectively kept the sea at bay in a few key areas regularly struck by high waves, constructing them around dozens of inhabited islands would be an impossible undertaking for the relatively poor country. And no amount of retainer wall would completely stave off the erosion of an island.
 

   
 

Photograph of Seawall

Naseer and Hatcher’s research could help the government of the Maldives determine where they could best allocate their limited resources for shoreline protection. Since the reefs exposed to the monsoons are wider and grow more vigorously, the islands they support should have the best chance of surviving rapidly rising seas. "We would already predict from our observations that those islands sitting on gently sloping reefs with broad reef flats and extensive sand flats have a much better chance of staying above sea level than those perched on pinnacles," says Hatcher. By building retainer walls only around these islands, the Maldives would probably have a greater chance of surviving as a nation.

In the future, the researchers’ aim is to construct a scientific model that could help them predict just how these reefs will take shape as the sea levels rise in the future. But for now Hatcher and Naseer need to return to the Maldives and verify their initial results on the ground. Only then will they be able to tell if their data will be of any practical use to the Maldives. "We are just at the very beginning of this project," says Hatcher. "We still have a long way to go until we achieve an adequate understanding of the large scale factors that determine the development of coral reefs."

References

1. Darwin, C., 1842: On the Structure and Distribution of Coral Reefs. Smith, Elder & Co., London.

2. Fagerstorm, J. A., 1987: The Evolution of Reef Communities. John Wiley & Sons, New York.

3. Huxley, T. H, 1873: On Coral and Coral Reefs. In Critiques and Addresses, Macmillan, London.

4. Nature Conservancy, 2000: Coral Reef Facts, Arlington, VA.

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Seawalls may be able to limit damage caused by rising sea level in the Maldives. To be effective, they must be placed on islands with broad reefs. (Photograph Copyright Ismail Faiz)

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