In the past few years of accelerated damage caused by climate change, one challenge had been increased flooding from sea-level rise (SLR). This threatens many coastlines, wetlands, and small Polynesian island nations such as Kiribati and Tuvalu, as well as the Maldives in the Indian Ocean. Scientists fear that global warming will cause these countries to disappear underwater, contrary to a new study revealing that coral reef islands can accelerate growth vertically in response to SLR.
The study by scientists from the University of Plymouth analyzed islands in the Pacific Ocean and the Caribbean Sea, seeing that the seemingly vulnerable coral reef islands have the ability to adapt and rise above intruding waves. Tides actually move sediment along the coast, increasing the reef's elevation and keeping these islands habitable.
Gerd Masselink, professor of coastal geomorphology, explains that 'the dominant discourse is that of an island drowning, and the outcome of that is coastal defenses and relocation ... We think there are more trajectories for the islands.'
A recent paper in NCC claims almost half of the world's beaches will go extinct by 2100 (https://t.co/sJ6LZu4gzL). I was asked to comment on this paper for a Science publication, but after having received my comment, they decided not to pursue to story. I am sharing it here. pic.twitter.com/NCYDHPqPQL — Gerd Masselink (@gmasselink) March 2, 2020
Moving Sediment
In general, all the islands are composed of sand or gravel atop a platform of living reef. They have formed millennia ago as a result of wave movement causing sediment, or reef material, to create the higher ground, which Masselink explains as a natural defense mechanism that continues today.
The team of scientists built a model coral reef and island in a laboratory tank with an SLR simulator to replicate real-time activity. 'Such island adjustment is driven by wave overtopping [and overwash] processes transferring sediment from the beachface to the island surface.,' notes the study
His team suggests that islanders should opt for climate-resistant infrastructure that can withstand natural flooding, such as movable houses so that inhabitants can adapt as their environment shifts. 'Dredging coral sand and sediments found in island lagoons and moving it to beaches could also aid the natural process of raising the islands.'
On the contrary, sea walls are hindering the island's natural ability to cope with SLR. He said, 'if you stop the flooding of the islands, you also stop the movement of the sediment on top of the island.'
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Better Perspective
Previously threatened by tsunamis, storms, SLR, and being told by experts of the threats of climate change, nations have already prepared to resettle their populations within decades. Coastal villages have searched for higher ground, others are building sea walls, while the call for international aid has resulted in multiple projects to alleviate global warming damage. While the majority of these tiny islands remain uninhabited, the few that live on the larger islands amount to about one million people who rely on fishing and tourism for their livelihood.
Hideki Kanamaru, natural resources officer with the UN Food and Agriculture Organization in Asia-Pacific, shared that this new information helps gain a better perspective on how to help these tiny island nations thrive and deal with global warming. Even as these islands adapt naturally to SLR, people still need to be cautious about reducing global warming and protecting their homelands, he added.
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