In recent years, the leaders and inhabitants of many small-island nations like the Maldives, Kiribati and Tuvalu have warned that climate change is an existential threat to their homelands, fearing they could disappear under rising seas as the planet warms.

But according to research published on Wednesday, small, low-lying islands dotted around the Pacific, the Caribbean and Asia — often seen as the places most vulnerable to global warming — can naturally adapt and raise themselves above encroaching waves.

A three-year study led by Britain’s University of Plymouth, which looked at coral reef islands such as the Maldives and the Marshall Islands, 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 … We think there are more trajectories for the islands,” said lead author Gerd Masselink, professor of coastal geomorphology at the University of Plymouth.

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.

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 world’s tens of thousands of coral reef islands are mostly uninhabited, but are home to about a million people who largely rely on fishing or tourism for a living, said Masselink.

Although the islands have different structures due to varying weather and wave patterns, they tend to be relatively small, low-lying, sandy or gravel islands sitting on top of a living reef platform.

They were formed hundreds of thousands of years ago by waves moving and piling up reef material or sediment to create higher ground — a natural defence mechanism that continues, he noted.

For the study published in the journal Science Advances, scientists built a model coral reef and island in a laboratory tank with rising water levels, and used computer simulations to replicate how such islands respond to higher seas in reality.

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, Masselink said.

Dredging coral sand and sediments found in island lagoons and moving it to beaches could also aid the natural process of raising the islands, he told the Thomson Reuters Foundation.

Sea walls, however, are compromising the natural ability of the islands to adjust to rising sea levels, he said.

“If you stop the flooding of the islands, you also stop the movement of the sediment on top of the island,” he said.

Most coral islands do not depend on agriculture, and import food and fresh water, making saltwater contamination during flooding less of an issue, he noted.

Hideki Kanamaru, natural resources officer with the UN Food and Agriculture Organisation in Asia-Pacific, said the study provided a “new perspective” on how island nations could tackle the challenge of sea-level rise.

But even if islands can adapt naturally to higher seas by raising their own crests, humans still need to double down on global warming and protection for island populations, he added.

Climate change in Maldives

Maldives comprises 1,190 islands in 20 atolls spread over 900km in the Indian Ocean. Of these, just 199 islands are inhabited with a population of slightly over 515,000 people. The highest point of land is two metres or about six feet above sea level.

The atolls of Maldives are ringed by the seventh largest coral reefs in the world and among the richest in species diversity. The reefs host over 1,900 species of fish, 187 coral species, and 350 crustaceans.

Drawn by its pristine beaches, underwater coral reefs, and spectacular marine wildlife, this small island-nation attracts some 1.5 million tourists annually. In recent years, nature-based tourism has served as the engine of growth for the economy and accounts for about 70 per cent of GDP.

Geography has made the Maldives especially vulnerable to the consequences of climate change. Being land scarce and low lying, the country is exposed to the risks of intensifying weather events such as damage caused by inundation, extreme winds, and flooding from storms.

With the melting of polar ice caps, the Maldives is also exposed to the risks of sea-level rise.

Rising sea temperatures also threaten the coral reefs and cause bleaching and death, with the most severe damage in areas that are stressed by pollutants, or damaged by physical disturbance.

Vulnerability to climate change hazards has been magnified by damage to coral reefs which has in turn impaired their protective function, thus a negative cycle of impact.

Note: The above article is largely based on reporting by Reuters. The cover photo has been sourced from Visit Maldives.