As Sea Levels Rise, Tiny Pacific Islands Might Not Sink, They Might Just Move Instead

The people of Kirbati might not sink under the waves, but they will nevertheless have to become more mobile, and new kinds of housing designs can help.

As Sea Levels Rise, Tiny Pacific Islands Might Not Sink, They Might Just Move Instead
[Top photo: Francesco Greco via Shutterstock]

Kiribati, an island nation in the middle of the Pacific Ocean, is one of the earliest clear-cut victims of climate change. The highest points on the main island are no more than two meters above sea level. Earlier this year, the president of Kiribati made headlines for spending $8.7 million on a piece of land in Fiji as a place to send climate refugees when waters rise.


But the whole story is more complicated, as Christopher Pala reported in the Atlantic after making a visit. When sea levels rise, some islands may actually rise with them.

“The islands that people live on in Kiribati are made of essentially sand and gravel, which is generated from the surrounding coral reef,” explained Paul Kench, head of the University of Auckland’s School of Environment. “Waves deposit that sediment to form an island. When sea levels go up, there’s a perception that islands are static and they can’t move. But in fact…the islands can build vertically.”

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As sea levels rise and more waves hit the low-lying islands in Kirbati, researchers like Kench expect that some of island material will be washed to higher elevations, helping raise the island’s height. Other material will probably be washed to other islands in the chain, building them up. It’s a process that has actually been happening for some time.

“When we look at satellite images for the last 30 to 40 years, and couple that with old aerial photographs from WWII, we can see that some islands have effectively migrated on their reef platforms,” says Kench. “We know that islands are starting to move, essentially, on the reef platform.”

That process, of course, is being amplified by climate change–and the fact that Kiribati’s tiny main island now has a population density approaching Tokyo or Hong Kong.

“One of the difficulties in having islands that move around a lot is that you have people living on them,” says Kench. “On the island of South Tarawa, 50,000 people live on a very small land area. When the island starts to change in places where you have very dense population pressures, that causes problems.”

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South Tarawa is only six square miles and very narrow, so people living near the coastline don’t really have room to move when sea levels rise. Still, some argue that doesn’t mean the population should move to a place like Fiji, in part because there’s plenty of room in other parts of Kiribati. Of the 33 islands that make up Kiribati, 21 are uninhabited.

It’s possible that if development on Kiribati radically shifted to a more mobile design, people could move as the islands evolve. A more distributed population could also help. The dense population in places like South Tarawa strains current resources like limited water supplies. Groundwater is threatened by rising sea levels–but also by pollution and mismanagement.

Current development built to protect the island may paradoxically be making the situation worse. “If you’re going to put a seawall along the coast, it’s essentially cutting off all the sand getting to the shoreline,” Kench says. “You can build walls higher to stop the sea getting in, but essentially once you do that you’ve gone from a naturally functioning island to an artificially constructed one.”

To plan ahead, Kiribati needs to better understand what’s happening now. “You really need to understand how your islands are changing–which islands are going to maybe get smaller, which are going to get larger,” Kench says. “And that gives you some power to actually plan how you are going to take your population and cope with the environmental changes going on into the future.”

About the author

Adele Peters is a staff writer at Fast Company who focuses on solutions to some of the world's largest problems, from climate change to homelessness. Previously, she worked with GOOD, BioLite, and the Sustainable Products and Solutions program at UC Berkeley.