Will Tuvalu Disappear Beneath the Sea?- page 3 | Travel | Smithsonian

Will Tuvalu Disappear Beneath the Sea?

Global warming threatens to swamp a small island nation

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The announcement fed skepticism of Tuvalu’s claims of impending doom. The nation’s leaders had just started asking Australia and New Zealand to accept Tuvaluans as environmental refugees; doubters now saw this lobbying as a ploy to further Tuvaluans’ economic prospects abroad. And “governments like those of Australia and the United States, which had been loud in their resistance to emissions targets, took heart,” recalls geographer Patrick Nunn of the University of the South Pacific in Fiji.

But hidden in the NTC’s findings was the reason Tuvalu’s sea level fell. An especially powerful run in 1997 and 1998 of El Niño—a periodic disruption of ocean and atmospheric systems in the tropical Pacific that causes warm water to slosh eastward—left Tuvalu temporarily higher and drier. John Hunter, an oceanographer in Hobart, Tasmania, reanalyzed the NTC’s records in combination with other data and found that sea level at Funafuti was in fact rising at about the same rate as the global mean. He also found that tidal maximums and minimums were growing more extreme year by year. As of this past December, the data from the Funafuti station show that sea level has risen there an average of 0.22 inches annually over the past decade.

New Zealand-based physical geographer Paul Kench, who has worked in Tuvalu, doesn’t question the prospect of future sea level rise. But he does suggest that low-lying islands like Tuvalu won’t necessarily be submerged. “Everyone thinks islands are all the same,” he says. “People believe islands are static dollops of concrete, so that when the water goes up, the islands will just drown.” But islands are not static, he goes on. Tuvalu and other atolls—ring-shaped coral islands surrounding a lagoon—are particularly dynamic, formed and replenished by coral gravels that break off the reefs and are tossed ashore. “The history of most small island states is littered with examples of islands growing in size, eroding away or fluctuating in response to changes in storm energy or cyclone winds,” he notes. In Tuvalu itself, Kench says, a few tiny islands actually grew after 1972’s Cyclone Bebe hurled rubble onto them.

Scientists generally assume that as sea level rises, sand and gravel erode away into the seabed as the shoreline recedes; accordingly, a place like Tuvalu will eventually disappear under a rising sea. “We think that’s nonsense,” Kench tells me. Instead, when big storms or rising sea levels send waves over a narrow atoll, he says, they can transport sand and other sediments across the island to the opposite shore. “It’s what happens on the sandy barrier islands off the U.S. East Coast,” says Kench, who has used computer models to test the scenario on atolls like Tuvalu. What the models projected, he says, was that waves washing over the island caused it to change shape and even move away from the reef edge, but not vanish.

Rising sea levels would prod the hard coral reefs just below the water surface to grow, building up the living shelf that helps protect shorelines. But most researchers believe that the increasing amounts of carbon dioxide dissolved in the water will retard the reefs’ growth, and high temperatures will destroy many coral species, leaving shorelines more vulnerable than ever.

In the short run, other manifestations of climate change pose more of a threat to Tuvalu than sea level rise. “What we’re already seeing in this region is more extreme weather events, though analysis of climate records is not complete,” says New Zealand climatologist Jim Salinger, an IPCC author and expert on the tropical Pacific. Then he gives an example that shows how just a little global warming can go a long way. “As you heat up the atmosphere, it rains harder when it rains; but when it doesn’t, things dry out faster because it’s hotter. You get more flooding and more drought.” Some scientists speculate that global warming may also increase the intensity of El Niño episodes, which spells trouble for Tuvalu because, Salinger says, “El Niños push cyclones toward Tuvalu.”

Kathleen McInnes, a senior climate modeler at Australia’s Commonwealth Scientific and Industrial Research Organisation, offers a similarly unsettling forecast for the island nation. “When warmer temperatures cause stronger cyclones to spin up, their lower central pressures can drive larger storm surges and waves right onto a place like Tuvalu,” she says. “Tuvalu is a submerged volcano in the middle of the ocean with no shallow shelf to dissipate the waves’ energy. Even waves from very distant storms can affect Tuvalu.”

Tuvaluans themselves tell story after story of fiercer and more frequent storms. I’m taken in an aluminum skiff to see the starkest evidence for Tuvalu’s claims. Funafuti Conservation Area Officer Semese Alefaio—Sam to visitors—tells the tale of two motus, or islands. First comes Tepuka, where we stroll through a lush forest, swim in clear waters and swig from a coconut that Sam splits open with his machete. This is the idyllic Before. Next comes a chilling After: barren, broken Tepuka-Sa-Vilivili, barely more than a sandbar where plastic bottles and other man-made rubbish run aground. “This used to be like the other motu,” Sam says, “before the big storms and waves started coming.”

If there’s little doubt that humankind is unwittingly nudging Tuvalu toward oblivion, the question is how to distribute the blame. During World War II, U.S. forces built a major staging ground in Tuvalu—then the British-ruled Ellice Islands—for an assault on Japanese-held Tarawa to the north. Ecologist Ursula Kaly says the serious erosion along Funafuti’s lagoon-front was set in motion by the wartime backfilling and building of sea walls, most of which disintegrated long ago.

Mataio Tekinene, Tuvalu’s director of environment, shows me where the coral building materials for Funafuti’s runway, sea walls and a dozen other World War II projects came from—deep pits in the porous coralline ground now filled with brackish water and trash. Islanders fear that a big storm could force churning seas through the pits and break through to the lagoon, flooding the island.

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