The previous president of Kiribati, a low-lying island nation in the Pacific, predicted that the country’s citizens would eventually become climate refugees, forced to relocate as sea level rise puts the islands underwater. But a new president elected in June now plans to elevate key areas of land above the rising seas instead.
In the right conditions, islands such as Kiribati’s—coral atolls that surround lagoons—can actually naturally grow as the sea rises, says Paul Kench, dean of science at Simon Fraser University, who has been studying how the islands respond to sea level rise and who advises the Kiribati government. “The islands are made up of sand and gravel, so essentially they’re really just large beaches,” he says. “The elevation and the shape of these islands are controlled by waves that interact with the reef and transport sand and gravel to form the islands.”
As Kench and other researchers studied satellite images from the last half century, they saw that many were getting larger and higher in elevation over time. Over the past decade, they’ve also observed that when large floods happen, the waves bring material to the top of the islands, raising the height.
On less populated islands in Kiribati, as this process happens naturally, some residents could move from one island to another that’s getting larger. “We’ve been urging the government to think about a comprehensive land-planning system, where they understand where all their land resources are and how they’re changing,” says Kench. “In some semi-urban or rural areas, communities could look at migrating from one island to a neighboring island over periods of 50 to 100 years.”
The most urban island in the country is more of a challenge, however, in part because seawalls that were built to prevent flooding also prevent the island’s natural growth. The country is considering plans to rebuild a road that was built on top of coral reefs when Kiribati was a British colony, turning it into an elevated bridge that restores some of the natural movement of water. But the country also plans to physically raise the height of the island by dredging the neighboring lagoon.
Something similar happened in the Maldives, where islanders face similar threats from sea level rise. “In the Maldives, they’ve already taken a step down the pathway, and they’ve dredged up and created an artificial island to help house 50,000 people,” Kench says. “And so we know the technology exists to do these rather large-scale projects.” Dredging sediment can damage coral reef ecosystems. But because key infrastructure on Kiribati’s capital island, such as the airport and hospital, can’t be easily relocated, the government sees the step as a necessary response to a problem it didn’t cause; Kiribati is responsible for around 0.0002% of global emissions.
The project will take time, so the planning will need to happen now so that the work can keep up with sea level rise. “The complexities are enormous, because we have structures and houses that are built on the ground,” says Kench. “So we would need to reenvision what a modern urban environment looks like in these islands.” That will likely involve rebuilding homes on stilts, even as the island gets higher, to protect against inevitable flooding. “You can imagine having to rebuild every house and rebuild the infrastructure—this is really a decade-long project,” he says. “The urgency is in getting on with the planning, securing the finance and the technological ability to pull this off. There’s time, but the window of time is shrinking.”