Coral reefs may be adaptable enough in the face of sea level rise to protect some of the vulnerable small island states at risk of disappearing beneath the water, according to new research published this week in the journal Science Advances.
The three-year study led by the University of Plymouth found that “small, low-lying islands dotted around the Pacific and the Caribbean—often seen as the places most vulnerable to global warming—can naturally adapt and raise themselves above encroaching waves,” the Thomson Reuters Foundation reports. The scientists “looked at coral reef islands such as the Maldives and the Marshall Islands,” and “found that tides move sediment to create higher elevation, a process that may keep the islands habitable.”
“The dominant discourse is that of an island drowning, and the outcome of that is coastal defences and relocation,” said lead author Gerd Masselink, a professor of coastal geomorphology at Plymouth. “We think there are more trajectories for the islands.”
Even in light of the new study, island populations willl still need protection from dangerous storms and other climate impacts. But the coral research suggests good news on at least one fundamental threat they face.
“Low-lying island states are judged to be at greatest risk from increasingly powerful storms and rising oceans, with some making preparations to resettle their people within decades,” Thomson Reuters says. “Many are already building sea walls, moving coastal villages to higher ground, appealing for international aid, or setting up projects to repair damage caused by climate change impacts.”
The study involved building a model coral reef and island in a laboratory tank with rising water levels, then using computer simulations to model the response of real-world islands to rising seas, the news agency explains. “The results suggest that by opting for climate-resilient infrastructure that allows for occasional flooding, like buildings on stilts and movable houses, islanders with enough space could adapt to their shifting environment,” the story states, citing Masselink. “Dredging coral sand and sediments found in island lagoons and moving it to beaches could also aid the natural process of raising the islands.”
But sea walls, ironically, may impede the coral islands’ natural ability to adapt to rising sea levels. “If you stop the flooding of the islands, you also stop the movement of the sediment on top of the island,” Masselink said.