A thin white smile curves across the blank face of the South Pacific Ocean, more than a mile below. Alittle lower, the whiteness resolves into an arc of breakers, and the tiny turboprop heads straight for them. Only at the last moment does a filament of land seem to emerge from the ocean. We touch down at Funafuti International Airport, Tuvalu’s only functioning airstrip, interrupting a soccer match on the runway.

The islands of Tuvalu, scattered over 500,000 square miles of equatorial ocean midway between Hawaii and Australia, appear so wispy and are so low-lying, no more than 15 feet above sea level, that it’s easy to visualize the waves just washing over them. It’s November, cyclone season, and I anxiously scan the area for high ground and finally settle on an unfinished three-story government building.

My uneasiness is stoked by dire pronouncements that Tuvalu’s leaders have been making for more than a decade. The planet’s fourth-smallest nation, they say, faces extinction because of climate change. Rising seas and deadly storms have reportedly started to swamp the islands, and fears are growing that Tuvalu will be uninhabitable or may vanish entirely within a few decades. Prime Minister Saufatu Sapo’aga told the United Nations last year that the global-warming threat is no different from “a slow and insidious form of terrorism against us.” Independent scientists also offer a grim forecast. “Because of its location and physical nature, Tuvalu is particularly susceptible to the adverse impacts of climate change and in particular rising sea level,” concludes a 1996 scientific study coauthored by the South Pacific Regional Environment Programme and the government of Japan.

Unlike other current or predicted environmental catastrophes, Tuvalu’s problem is one that people worldwide are believed to create by burning fossil fuels that release carbon dioxide into the atmosphere, contributing to global warming. In that sense, my habit of leaving lights on around my house, in Washington, D.C., a neighbor’s of constantly driving his large SUV to go just a few city blocks and another neighbor’s preference for a toasty house in winter would play a role in Tuvalu’s fate. In fact, Tuvalu threatened in 2002 to sue the United States and Australia for excessive carbon dioxide emissions. Meanwhile, some Tuvaluans are getting ready to abandon their homeland. “Islanders Consider Exodus as Sea Level Rises,” the British newspaper The Guardian reported last year.

A new Atlantis? Maybe. But not all scientists agree that Tuvalu’s future is underwater. Some critics have branded island leaders as opportunists angling for foreign handouts and special recognition for would-be “environmental refugees” who, they say, are exploiting the crisis to gain entry to New Zealand and Australia. Others have even said that people and organizations sympathetic to Tuvalu are “eco-imperialists” intent on imposing their alarmist environmental views on the rest of the world.

The challenge is to see through the fog of rhetoric and conflicting scientific views to where global climate theory might—or might not—intersect with Tuvalu’s people. But that’s surprisingly difficult to do. Most experts who have weighed in on the matter haven’t visited Tuvalu, and those who have made the journey typically have an agenda of their own. “Everyone arrives with a story,” says Ursula Kaly, an Australian ecologist and former longtime environmental adviser to Tuvalu. “Their minds are made up beforehand.” After I toured Tuvalu, reviewed the scientific evidence and spoke with climate experts and other scientists, I gathered that the nation and its nearly 10,000 people are indeed in trouble and may even be doomed. But rising seas are only part of the problem.

This afternoon the wind is shrieking, the sky is gunmetal gray and the rain falls in thick sheets. Despite the deluge, the good news, says Hilia Vavae, the nation’s chief meteorologist, is that seawater doesn’t seem to be infiltrating neighborhood wells and taro patches or flooding onto the airport runway.

A rangy woman of middle years, Vavae cuts an unusual figure in her native Tuvalu: she is an Australian-trained scientist and a Muslim in a traditional and Christian society. Lately, she has also played Cassandra to her laid-back countrypeople. “I think we have a lot to worry about,” she says later in her computer-filled office. “Cyclones and tropical storms have been getting much worse since the 1980s. We had a big drought starting in 1999. Flooding from extreme high tides is increasing also.” Big swells and freak waves are washing over the island more frequently. And then there’s a different kind of flood. “In the late 1990s, water started coming out of the ground—first puddles, then a whole sea. That had nothing to do with rain.” The net effect, Vavae says, is that little by little Tuvalu is beginning to wash away.

Other islanders say much the same. Tauala Katea, a young employee at the meteorology station, says that ten feet of beachfront have disappeared over the past decade on the island of Vaitupu. Falealuga Apelamo, 77, a retired fisherman and farmer, says one small islet from the nearby atoll of Nukufetau has “drowned,” another is almost gone and the sea is crashing through a third. “The big waves and winds and storms used to come in November and December,” he adds. “Now it’s any time of the year.” At the northern tip of Funafuti, a gun emplacement, planted on dry land by U.S. soldiers in World War II, now sits 20 feet offshore. At the southern end, old-timers say, their meeting hall used to stand in the middle of the village. Now it is waterfront property.

It’s this sort of devastation that prompts Tuvalu’s leaders to cry foul. “The rest of the world should act immediately and together to cut down on its use of greenhouse gases,” says Paani Laupepa, an assistant secretary in Tuvalu’s Department of Foreign Affairs, headquartered on the second floor of a private home in Funafuti. By “rest of the world,” Laupepa mostly means the United States and Australia, the world’s largest overall and highest per capita producers, respectively, of greenhouse gases—and the only developed countries that declined to ratify the 1997 Kyoto Protocol, which calls for gradually reducing emissions of those gases. (U.S. officials say the protocol doesn’t cover developing countries, sets arbitrary emission-reduction targets and would harm the economy.) “The United States, with a small percentage of the world’s people, uses 25 percent of the world’s resources,” Laupepa goes on. “You Americans have a good lifestyle, all the conveniences, three or four cars per family. You need to appreciate the impact that has on our lives here.”

Scientists first speculated about a link between carbon dioxide and atmospheric temperatures in the 19th century. But highly accurate measurements of atmospheric carbon dioxide levels didn’t begin until 1958, when oceanographer Charles David Keeling of the Scripps Institution of Oceanography installed instruments atop Mauna Loa on the island of Hawaii. His findings of yearto- year increases are universally accepted. Beginning in the 1980s, analysis of deep ice-core samples extracted from ancient glaciers in East Antarctica and Greenland have yielded historical data on temperature and the atmosphere’s chemical makeup.

The ice-core research shows a striking correlation between carbon dioxide levels and temperature. Moreover, carbon dioxide levels are now higher than at any time in the past 440,000 years. Before the Industrial Revolution, atmospheric carbon dioxide concentrations remained relatively flat. Since then, they have climbed by nearly a third and are now increasing at the unprecedented rate of 0.4 percent a year. And since the last ice age, about half the world’s forest cover has been lost, and along with it an important mechanism for soaking up atmospheric carbon dioxide.

In the past century, average global temperatures at the earth’s surface climbed by about 1.08 degrees Fahrenheit (.6 degrees Celsius) to their highest in at least a millennium. During the past 25 years, the rate of temperature increase has been even greater, about 3.6 degrees F, if extrapolated over a century. The ten warmest years since 1860 have all occurred since 1990, with 1998 being the warmest of all, according to the federal NationalClimaticDataCenter. The years 2002 and 2003 are virtually tied for second place.

At the same time, researchers have documented changes consistent with an enhanced greenhouse effect. The world’s landmasses aren’t cooling off nearly as much as they used to when night falls. Less snow covers the Northern Hemispherein winter. Less sea ice appears in the Arctic in spring and summer. Glaciers are retreating and shrinking, sometimes drastically; Mount Kenya’s largest glacier has shrunk by more than 90 percent; Kilimanjaro’s glaciers, by more than 70 percent; and 14 of Spain’s 27 glaciers have disappeared altogether since 1980. Habitats for a number of plants and animals are moving to higher (cooler) latitudes. Warming spells threaten tropical reefs.

Scientists say they have ruled out natural causes, such as a periodic surge in the sun’s output and volcanic activity, as an explanation for the climate change. “There is new and stronger evidence that most of the warming observed over the past 50 years is attributable to human activities,” concludes Climate Change 2001, the third assessment report of the Intergovernmental Panel on Climate Change (IPCC), established by the World Meteorological Organization and the United Nations Environmental Programme. The report represents some 1,300 authors and 1,200 expert reviewers and editors and 100 national governments. Similar conclusions were reached by a 2001 U.S. National Research Council panel and U.S. Climate Action Report 2002, a multiagency project that Secretary of State Colin Powell submitted to the U.N.

Despite such an emerging scientific consensus, the Bush administration says that additional scientific data are needed to warrant the economic disruptions that mandatory carbon dioxide reductions would cause. U.S. Senior Climate Negotiator Harlan Watson has said the administration’s approach to reducing greenhouse gas emissions was based principally on voluntary efforts and developing new, more fuel-efficient technologies. Yet the White House stirred controversy last year when it deleted sections of the Environmental Protection Agency’s draft report on the state of the environment that referred to human contributions to climate change. Meanwhile, the federal Energy Information Administration is forecasting that U.S. carbon dioxide emissions from energy use will grow by nearly 40 percent in the next 20 years.

To the extent that disagreement exists within the scientific community, it relates to the future—how severe global warming is likely to be and what its effects will look like. Scientists use global climate models to develop scenarios. All the models project a warmer future: between 2.5 to 10.4 degrees F warmer by 2100. Even at the lowest end of the projected range, temperatures will climb more than twice as much this century as they did during the 20th. The projected increase, the IPCC report says, “is very likely to be without precedent during at least the last 10,000 years.” The models also project that global sea levels will rise between 3.5 and 34.6 inches this century—and continue to rise for centuries. Even a lower-end sea-level rise of 11.8 inches would cause a typical shoreline to retreat 98 feet. Most of the projected rise will occur because water expands as it warms, but some of it will come from the melting of glaciers and ice caps.

Still, accurately gauging sea level is complicated and can quickly become a matter not of science but of politics, as Tuvaluans have recently learned.

On Funafuti’s deep-sea wharf is a structure that resembles a portable toilet enclosed in a wire-mesh fence. It is one of 12 monitoring stations around the Pacific that the Australian government has established since 1992 “to measure sea level and associated meteorological parameters.”

The controversy began in 2000, when then director of Australia’s National Tidal Centre (NTC), Wolfgang Scherer, announced that after seven years of measurements around the Pacific “there is no acceleration in sea level rise—none that we can discern at all.” Tuvalu, in particular, got a pie in the face: the NTC announced that sea level at Funafuti had actually fallen by 3.42 inches since 1993. “Falling Sea Level Upsets Theory of Global Warming” read a headline from the LondonTelegraph at the time.

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.

But the armed forces aren’t the only guilty parties. Residents quarried for rocks, gravel and even sand for building materials, Tekinene says, promoting erosion. These days, construction materials for big projects must be imported. International aid organizations have also contributed to the problem—for instance, by encouraging Tuvaluans in the late 1980s to replenish a sea wall with beach rubble tossed ashore by a cyclone. The wall has disintegrated, and the shoreline, once protected by the rubble, is exposed.

And then there’s the population boom. Since 1980, the population of Funafuti has more than doubled, from about 2,000 to 4,500, or almost half of Tuvalu’s citizenry. “It can be a little tricky to judge which environmental effects are induced locally by humans and which are created by human societies outside Tuvalu,” Tekinene says.

In a way, Tuvalu is the planet writ small. Its poor environmental stewardship (which may hasten the effects of global warming) is no more egregious than that of most other, bigger countries. But because it is fragile, remote, resource-poor and low-lying, Tuvalu has less room for error than most other nations. The consequences—and the future—arrive sooner. And with greater force.

In a spotless kitchen decorated with children’s drawings in suburban Auckland, New Zealand, I drink tea with Koloa Talake, a Tuvalu native and the nation’s prime minister for nine months starting in December 2001. Talake had served on the board of a California company that in 2000 purchased the rights to Tuvalu’s Internet domain address extension (.tv), and he helped negotiate its resale to another U.S. company in 2002. That same year,Talake announced that Tuvalu, joined by Kiribati and the Maldives, planned to sue the United States and Australia at the International Court of Justice in the Hague. The plaintiffs had planned to argue that the developed nations’ disproportionate carbon dioxide emissions contributed to global warming, which poses a threat to the islanders. But Talake failed in his reelection bid later that year, and the new government has not pursued the litigation. Whether a nation could prevail in such a lawsuit is open to question. For one thing, establishing a direct link between a particular nation’s greenhouse gas emissions and harm to Tuvalu is problematic. For another, the United States does not accept the jurisdiction of most international courts.

Talake says he had hoped his lawsuits would bring Tuvalu “several million dollars for the damage caused by emissions.” But that was secondary, he adds: “We are asking for a place to live if the tide comes against us. There are a lot of places in Australia and maybe America with no people.” He and his wife, Tilesa, now live in Auckland, along with their two sons, an engineer and a chef, and their families. “We have no children left in Tuvalu to take care of us,” he says.

Talake is part of a growing Tuvaluan community in New Zealand of some 2,000. Affluent Tuvaluans have long traveled here for higher education and good healthcare, but today’s newcomers more often pick strawberries for a living. I meet some of them at a church service in an Auckland suburb on a gray, blustery Sunday. The Reverend Suamalie Iosefa smiles broadly. But his face is weary. As a preacher and mental health worker, he deals with problems born of poverty and overcrowding, not to mention the shock of social dislocation. “Imagine moving from a nation without a stoplight to a modern city of a million people,” he says.

Iosefa thinks New Zealand offers a brighter future than Tuvalu “education-wise, health-wise, and especially because people feel threatened by global warming.” Acknowledging that threat, New Zealand’s government in 2002 established a new quota program for Pacific Islanders, which allows up to 75 Tuvaluans a year to immigrate. But Iosefa says no more than 21 people were approved in 2003.

As the voices of the men’s and women’s choirs rise in the hall, the stalwart hymns of England take wing on the rich harmonies of Polynesia. Most of the assembled, some 200 adults and children, sit or recline on mats. A quarter of the people in the room have overstayed their visas and face deportation. But Sutema Keakea, who has two young daughters and is 39 weeks pregnant, is among the lucky ones. A bank employee in Tuvalu, she just received approval for permanent residency under the new program. She left Tuvalu to be near other relatives, she says: “People do say they’re afraid of global warming and sea level rise, but I just don’t know.”

On this day, some of the Tuvaluans say they ponder the story of Noah and the Flood for clues to their future. “In Noah,” says one man, “the rainbow was a sign of God’s promise that there won’t ever be another flood again.” But another congregant disagrees. “Sea level will rise because things are different now from the old days,” he says. “The world God created was perfect, but people have made it imperfect.”