Will Pacific Island Nations Disappear as Seas Rise? Maybe Not

“If you were faced with the threat of the disappearance of your nation, what would you do?”

That’s the question Enele Sopoaga, the prime minister of the tiny Pacific Island nation of Tuvalu, asked fellow world leaders at the United Nations climate summit in Lima, Peru, in December.

It’s a question that leaders of Pacific Island states have been asking for decades. As a warming climate drives sea levels upward, low-lying island nations face an uncertain future—or no future at all, say these leaders, who warn of their nations’ imminent disappearance.

Officials in Tuvalu, 600 miles (965 kilometers) north of Fiji, have been some of the most vocal critics of the world’s large greenhouse gas emitters—industrialized nations such as the United States and China—which they accuse of not doing enough to curb emissions, contributing to the melting of ice sheets and rising seas.

“I carry a huge burden and responsibility,” Sopoaga told the climate summit delegates in Peru. “It keeps me awake at night. Will we survive? Or will we disappear under the sea?”

These are desperate questions. But how real is the threat? Are island nations like Tuvalu, where most of the land is barely above sea level, destined to sink beneath the waves, like modern-day Atlantises?

Not necessarily, according to a growing body of evidence amassed by New Zealand coastal geomorphologist Paul Kench, of the University of Auckland’s School of Environment, and colleagues in Australia and Fiji, who have been studying how reef islands in the Pacific and Indian Oceans respond to rising sea levels.

They found that reef islands change shape and move around in response to shifting sediments, and that many of them are growing in size, not shrinking, as sea level inches upward. The implication is that many islands—especially less developed ones with few permanent structures—may cope with rising seas well into the next century.

But for the areas that have been transformed by human development, such as the capitals of Kiribati, Tuvalu, and Maldives, the future is considerably gloomier. That’s largely because their many structures—seawalls, roads, and water and electricity systems—are locked in place.

Their analysis, which now extends to more than 600 coral reef islands in the Pacific and Indian Oceans, indicates that about 80 percent of the islands have remained stable or increased in size (roughly 40 percent in each category). Only 20 percent have shown the net reduction that’s widely assumed to be a typical island’s fate when sea level rises.

Some islands grew by as much as 14 acres (5.6 hectares) in a single decade, and Tuvalu’s main atoll, Funafuti—33 islands distributed around the rim of a large lagoon—has gained 75 acres (32 hectares) of land during the past 115 years.

Two-thirds of the reef islands in the study migrated lagoon-ward as their ocean-side coastlines eroded and sediment built up on the side facing the lagoon. One of Funafuti’s islands shifted more than 350 feet (106 meters) over 40 years.

Reef islands, Kench says, are among the most dynamic landforms on Earth. And Tuvalu’s are some of the most dynamic on record.

With a scant ten square miles (26 square kilometers) of dry land, Tuvalu is one of the smallest countries in the world. Although there are many atolls and islands in the group, which lies midway between Australia and Hawaii, more than half of Tuvalu’s 12,000 people live on just one island—Fongafale—on the eastern rim of Funafuti atoll.

Business as Usual

I first came to Tuvalu ten years ago, my interest piqued by news reports suggesting (and sometimes stating outright) that the islands were doomed. Journalists had latched on to countries such as Tuvalu, Kiribati, and Maldives as the environmental hard-luck stories of the new millennium.

These postcard paradises had become poster children for a planetary crisis, with their inhabitants cast as the world’s first climate refugees. “Tuvalu Sinks Today—The Rest of Us Tomorrow?” was a typical headline.

A prominent environmental campaigner had declared that Tuvalu’s leaders had “conceded defeat in their battle with the rising sea, announcing that they will abandon their homeland.”

A similar claim was made in Al Gore’s documentary, An Inconvenient Truth.

“The evacuation and shutting down of a nation has begun,” reported the British Guardian newspaper.

That islands like Tuvalu face an intensifying barrage of climate impacts is not in doubt.

Besides the damage inflicted by sea-level rise itself—coastal erosion, surface flooding, and saltwater intrusion into soil and groundwater—they will suffer from increasingly frequent and severe weather extremes (droughts and cyclones) and die-offs of their coral reefs through ocean warming and acidification, leading to potential collapse of marine ecosystems that provide food and livelihoods for island dwellers.

But from what I could see, in 2004 it was business as usual in Funafuti. Government staff were about to move into a brand-new building overlooking the lagoon. The country’s first cell-phone tower had just been erected. Tuvalu was enjoying a windfall profit from the sale of its “dot tv” Internet suffix. Tuvaluans seemed in no hurry to evacuate their supposedly disappearing homeland.

In November 2014, armed with Kench’s findings, I returned to Tuvalu to see whether anything had changed. The first thing I noticed was that Fongafale was even more crowded than before. According to the 2012 census, Fongafale’s population had increased by 1,500 since my earlier visit, to more than 6,000. So much for the shutting down of a nation.

Island Building

I hired a fishing dory and made a spray-drenched trip across Funafuti’s 106-square-mile (275-square-kilometer) lagoon to an uninhabited island called Tepuka. It has the classic appearance of an atoll island: a pancake of sand with a mop of vegetation and, floating above, a confetti of seabirds.

Such islands look static, but they are perpetual construction sites. Their surrounding coral reefs are factories that produce a constant supply of raw building material: calcium carbonate.

The factory “workers” are biological agents that turn the skeletons of corals and other carbonate-containing creatures into sediment. Fish, sea urchins, and sponges are the principal processors. In one year they can produce four pounds of sediment per square foot (21 kilograms per square meter) of reef.

Reef Loss, Island Gain

Some climate specialists believe that rising sea-surface temperatures and increasing ocean acidity may have an even more damaging impact on coral reefs than that caused by sea-level rise.

Since the beginning of the industrial period, some 250 years ago, the acidity of tropical surface waters has risen by 30 percent. Sea-surface temperatures have increased by about 1.8°F (1°C) during the past century.

High water temperatures kill corals, and acidification affects their ability to produce their skeletons, since calcium carbonate dissolves in acid. Laboratory experiments suggest that the calcification rate of some corals could decrease by a third over the next three to five decades.

Yet a reef’s loss of living coral can be an island’s gain—at least in the short term. In 1998, when a worldwide coral bleaching event killed up to one-sixth of the world’s reefs, a huge repository of coral rubble became available for island building. If heat-related coral die-offs occur in coming decades, the sediment supply for islands is likely to increase.

But Kench cautions that scientists don’t yet have a clear understanding of how changes in ocean chemistry will affect coral reefs, or how that might translate to islands. “We don’t have a good handle on the time lag between when coral is killed and when it becomes available to an island as sand,” he says.

Over the time scales that matter to island nations—the next few decades when they’ll be seeking to adapt to land changes—the critical factor, Kench says, is the reworking of sands and gravels around the reef islands. “And that’s controlled by wave processes and whether there’s sediment available. If sand is still being produced, islands are able to adjust and maintain their area.”

For Urban Islands, an Uphill Battle

“Urban islands are in trouble because they’ve lost their capacity to adapt,” Kench says. “They’re environmentally degraded. Their reefs are damaged, the sedimentation processes are undermined, and the islands aren’t actively connected to their reefs. For densely urban centers, the only strategies to cope with rising sea levels will be engineered ones.”

Malé, the capital of Maldives—a 1,200-atoll archipelago in the Indian Ocean, and one of the countries predicted to be most affected by climate change and rising seas—is such an island. It’s encircled by built structures such as seawalls, breakwaters, harbors, and artificial beaches.

“Heavily fortified,” is how Mohamed Aslam, an oceanographer by training and until 2012 the environment minister for Maldives, described it to me.

“There’s no room for natural processes to take place,” he says. “I suppose if you spent enough money, you could continue to keep the sea out. But it’s prohibitively expensive for a country with a small population and a small GDP to do that sort of thing on every island.”