Can atoll islands survive rising sea levels? Researchers aim to find out

An international research project led by the University of Plymouth will explore the potential for low-lying coral atoll islands to survive the predicted rise in sea level.

Atoll islands, commonly found in the Indian and Pacific Oceans, are wave-built accumulations of gravel or sand that sit on top of coral reef platforms.

Forecasts based on existing hydrodynamic models predict that sea-level rise will make most of them uninhabitable within decades.

The new 5-year project, set to start in January 2024, is being led by the Coastal Processes Research Group, which has previously led studies suggesting that island “drowning” is far from inevitable.

“The rise in sea levels as a result of climate change is going to place many coastal communities under threat … [and] it has largely been assumed that these coral atoll islands could just disappear,” says principal investigator and Professor of Coastal Geomorphology at the University of Plymouth, Gerd Masselink.

“Our previous research has suggested that is not a foregone conclusion, and this project will establish the processes at play, as well as supporting the communities that call these islands home, by identifying and evaluating adaptation strategies.”

The $5.3m project will include field tests in the Maldives and the Pacific, as well as laboratory-based experiments in the largest wave flume in the world – the Delta Flume in the Netherlands.

The team will also analyse the atoll islands’ response to cyclones and other extreme wave events.

Models developed from the data will be used to evaluate how the island atolls might respond to short and long-term sea level rise.

“Atoll islands have been created over hundreds to thousands of years by ocean waves, and their future is intrinsically connected to it. The ecology of the reefs they sit on is also under threat, but their survival is critically important to the island’s survival,” says Masselink.

“The big question is whether all of that can keep up with sea level rise, and answering that is crucial for both the islands and the people who live on them.”