Where the Waters Are Rising

By J. MADELEINE NASH

Its prow angled high, the speedboat skims across an iridescent lagoon that shivers with wind-whipped chop. Just ahead looms the island city of Male, bustling capital of the Republic of Maldives, about 400 miles southwest of the southern tip of India. Clearly visible is the low line of motorized dhonis tethered in the harbor, and just beyond the boats, a row of multistory buildings that seem to be floating like a mirage. Exactly where, I find myself wondering, does the sea end and the land begin? For Male--with its crowded shopping streets, its lively fish market, its gold-domed Friday mosque--might just as well have been built on a lily pad, so low does it ride in the water.

Most of the time, that lack of elevation makes no difference. But occasionally it makes a big one--as it did that Sunday morning late last year when waves triggered by the great tsunami of 2004 spilled over sea walls to flood the city with sand-clouded water and then swept out just as suddenly, leaving behind a visceral feeling of foreboding. For what has the more thoughtful of Male's 80,000 or so residents worried is that such intrusions will become more frequent, not because of the sudden onslaught of tsunamis but as a result of the slow, relentless effects of global warming on the sea that surrounds them.

The 1,192 islands of the Maldives make up what's arguably the lowest-lying country in the world. The average elevation is a little more than 3 ft. above sea level, and what's considered high ground tops out at under 10 ft. Even now, storm surges combined with heavy rains and high tides can be counted upon to cause serious problems somewhere in the country at least once a decade. But people here are haunted by the specter of the disasters to come if--as seems inevitable--greenhouse effects cause sea levels to rise higher and higher. Indeed, it was Maldives' President Maumoon Abdul Gayoom who first raised the issue of global climate change from the perspective of a small island nation to the U.N.'s General Assembly nearly two decades ago.

But even though public awareness about global warming has grown significantly since then--and even though evidence that temperatures are rising now seems incontrovertible--there hasn't been a great deal of progress in dealing with it. Paradoxically, that is partly because of the success of the environmental movement, which celebrates a major milestone this week: the 35th anniversary of the first Earth Day on April 22, 1970. Back then a dedicated band of ecology-minded crusaders set out to save the planet with the same sort of idealistic, confrontational activism that was working so well for Vietnam War protesters and the women's movement.

And, to a degree that's easy to lose sight of today, their efforts succeeded. Air and water in most of the developed world are dramatically cleaner than they were in 1970. Millions of acres of forests, wetlands and wilderness have been preserved. Once endangered species like the bald eagle and the American alligator are thriving. And while the situation is much less rosy in many parts of the world, environmental values have been so firmly incorporated into the American psyche that the recycling bins in millions of homes and offices and on street corners, which would have seemed positively radical back in 1970, don't merit a second glance. Quite a few consumers go out of their way to buy such products as hybrid cars and environmentally friendly coffee. And a number of corporations that were once considered the enemy are working with environmental groups to find ways to be more responsible.

So many battles have been won, in fact, that it's harder to rile up the public than it once was, particularly when the problem seems so diffuse, the threat so distant. The result? Vast quantities of carbon dioxide from the burning of oil, coal, wood and natural gas have entered the atmosphere, where they will remain for well over 100 years. The 1997 Kyoto Protocol calls for developed nations to roll back emissions below 1990 levels. But even if that goal were achieved today, it's already too late to stop some degree of warming from occurring. That means we may soon start seeing unpredictable and potentially destabilizing changes in weather patterns and ocean currents.

And for certain it means that the sea, expanding as it heats up, will rise. Sure, says climatologist Tom Wigley of the National Center for Atmospheric Research in Boulder, Colo., we can do things that temper the eventual extent of that rise--which could be as little as 4 in. or as much as 3 ft. by the year 2105--but we can do nothing about the sea-level increase to which the climate system is already committed. That's because big wheels in the atmosphere and ocean have started to turn. No matter what humans do, the oceans will continue to rise through the end of this century and well beyond--and the more carbon dioxide humans pump out, the higher the oceans are likely to go.

This is terrifying news for the 300,000 or so souls who live in the Maldives, but it could also spell disaster for people living on or near the sea everywhere--in Venice, Rio de Janeiro, Tokyo, New York City, the Nile delta in Egypt, the Ganges delta in Bangladesh or the Mississippi delta on the U.S. Gulf Coast. In all, perhaps 3 billion people, half the world's population, live within a hundred miles of the sea. And at least 100 million of them occupy low-lying deltas that, like the Maldives, rise not much more than 3 ft. above sea level. "Whatever our fate tomorrow," Maldives President Gayoom is fond of remarking, "will be your fate the day after tomorrow."

But what is that fate exactly? Is it really to disappear beneath the jewel-toned waters of the Indian Ocean? This is a question I came back to again and again during the course of my weeklong visit.

HOW FAR, HOW FAST?

On a pier off the airport island, justa cross the lagoon from Male, is a tide gauge that has been beaming data to the University of Hawaii Sea Level Center in Honolulu since 1989. The good news, says the center's director, oceanographer Mark Merrifield, is that sea levels around Male do not appear to be rising quite as fast as in many other places in the world. That may sound odd, but the simple expansion of water as it warms is complicated by local wind and current patterns. Beyond that, changes in the height of land masses as soils compact or tectonic plates slip and slide can offset--or magnify--sea-level changes.

The bad news: across a big swath of the globe, the sea is still rising, eroding what for low-lying places was already a slim margin of safety. Making the problem even worse is the loss of what Florida International University coastal expert Stephen Leatherman calls "living landforms," which would otherwise buffer that rise. Consider the wetlands that are an integral part of all river deltas, he says. Plants trap sediment from floodwaters flowing downriver, and the more they trap, the higher these wetlands grow. The problem is, people don't much like floods, so they build levees, which keep sediments from washing out of the rivers. They also don't much like wetlands, so they drain them. As a result, the world's river deltas are sinking rather than rising. To a large extent, the increased impact of flooding in places like New Orleans and Venice is self inflicted.

Whether the islands of the Maldives are subsiding is uncertain. Clearly Male is not yet in the same pickle as Venice, where a combination of sinking land and rising seas has opened the city to regular inundation by storm-generated waves and unusually high tides. Still, it won't take much of a rise in sea level--between 6 in. and 1 ft., says Ahmed Ali Manik, senior environmental analyst in the Ministry of Environment and Construction--before the southwestern corner of the Maldivian capital will be threatened by the same problem. And a 3-ft. rise would allow the biggest tides to wash over the whole city.

How long does Male have before that happens? It depends. At present the global rate of increase is between 2 mm and 3 mm a year, around a tenth of an inch, meaning it will take about a century to produce a 1-ft. rise. This is cause for concern, of course, but a 1-ft. rise in sea level over the course of a century or more is unlikely to prove fatal. A century, after all, is a long time--long enough to raise sea walls and breakwaters and to adapt in myriad other ways.

But that rate could accelerate. Starting in the 1990s, say scientists, ocean temperatures have been increasing at a faster clip--enough to more than double their contribution to sea-level rise. At the same time, the global warming has dramatically increased the meltwater and ice discharged by glaciers, ice caps and ice sheets. It's still unclear whether other factors--such as changes in the amount of snow that falls on Antarctica or the amount of water trapped in reservoirs--will speed the rise in ocean levels or slow it, or even send it into reverse.

ROBUST OR FRAGILE?

The islands of the Maldives--little circles and half-moons of platinum sand--seem as fragile as they are exquisite. To see them is to marvel--as Charles Darwin did--that they did not long ago succumb to "the all-powerful and never-tiring waves." But as Darwin went on to explain, these islands are more substantial than they seem. They are in fact the visible crests of massive limestone reefs that extend from the sea floor to the surface. The limestone is made of the consolidated skeletons of tiny marine organisms, including untold generations of coral polyps that millions of years ago began growing on the slopes of a long-vanished volcanic mountain chain--and have kept pace with sea level ever since.

This is not to say the Maldives have remained the same over time. Twenty thousand years ago, at the height of the last Ice Age, says Abdulla Naseer, director of the Marine Research Center in Male, the Maldives were not the low-lying coral islands we see today. Due to frigid ocean temperatures and vast amounts of water locked up as ice, sea levels were some 400 ft. lower then, and the reef crests loomed above the sea's surface as sheer-sided limestone pinnacles. Then, as the earth warmed and the ice melted, the rising ocean overtopped these pinnacles, providing new surfaces for the corals to colonize. Around 5,000 years ago, after the corals brought the reefs close enough to the sea's surface, coral sand and gravel began to accumulate in shallow depressions, and the present-day islands formed.

These islands are extremely dynamic, continuously changing shape in response to shifts in the monsoon winds. Each year, in fact, sand swirls around with the waves; beaches grow in one season and shrink in the next; and this process has been going on for a very long time. Geographer Paul Kench of New Zealand's University of Auckland has collected evidence suggesting that the islands of the Maldives emerged from the sea when their reefs were quite a bit lower than today, meaning that larger, more energetic waves would have slammed into them during a critical formative period. In their natural state, Kench thinks, the islands might prove remarkably resilient in the face of sea-level rise.

Of course, the people who live on such islands want protection from marauding waves, and for millenniums the islands' reefs have provided it. The value of that protection became clear in 1987 after Male expanded out to the edge of its reef, burying it beneath a thick layer of coral sand and gravel. In April of that year, an armada of giant waves--stirred up, some think, by a distant cyclone in the Indian Ocean--attacked the city, gouging out big chunks of landfill and nearly washing away the car in which Gayoom was riding. A short time later, he gave the first of a series of famous speeches that invoked the image of the Maldives being swallowed by the sea.

With help from the Japanese, the Maldivian government has shored up Male's perimeters with sea walls and breakwaters (at a cost of $60 million, about 10% of the nation's gross domestic product in 2002). It has also taken steps to protect the living coral breakwaters that shield the rest of the island chain. Among other things, it has banned the mining of coral stone that for centuries has been used by villagers to construct mosques and houses. But what the government can't control is the temperature of the surrounding ocean--and that does not bode well for the future.

The reason? Healthy reefs are capable of growing upward in response to higher sea levels. But when ocean temperatures rise too high, coral polyps become susceptible to a disease known as bleaching, so-called because it involves loss of the symbiotic algae that not only provide the polyps with essential nutrition but also color their tissues. Like a fever, bleaching is not necessarily fatal, but can be if ocean temperatures stay too high for too long. That's what happened seven years ago, when a prolonged heightening of sea-surface temperatures, triggered by the 1997-1998 El Nino, ripped through the Indian Ocean like a forest fire. In some areas, coral mortality approached 70%. The reefs are recovering, says Abdul Azeez Abdul Hakeem, director of conservation for the Banyan Tree resort, but no one knows what will happen to them as the world's oceans continue to warm.

In some ways, the 1998 bleaching epidemic was almost as shocking as the damage inflicted by the tsunami, for the reefs are more than passive bulwarks against the sea; they are also the beating heart of the country's economy. The reefs provide habitat for the baitfish used by the local tuna fishery, and their underwater beauty lures hordes of foreign tourists. "If your heart stops beating, can you survive?" asks Ahmed Shaheed, the Maldives' chief government spokesman.

STAY OR MOVE?

the village of Naalaafushi seems like a place out of time, where people drowse through the heat of the day beneath the shade of hibiscus trees and coconut palms. It's a charming island. It's also extremely small, not much more than a quarter-mile across. From the sandy street that runs through the center of town, you can see both the brilliant turquoise of the interior lagoon and, on the other side, waves breaking on the shallow reef that faces the Indian Ocean. There are dozens of islands like Naalaafushi in the Maldives--too many, say government officials, to provide with essential services, let alone shore up against the sea. In time, they hope, the residents of these islands (some of which have populations of not much more than 100 people) will be enticed to move to larger, more secure places like Hulhumale, an artificial island being built from scratch just across the lagoon from the capital. Hulhumale is rather barren looking, but it has one very attractive feature--it towers more than 6 ft. above sea level, twice the elevation of most of Male.

Other ambitious projects are in the works as well, says Hamdun Hameed, Minister of Planning and National Development, pulling out a map of the islands, each one a dot on a ring of reef--an atoll--that traces out the shape of the mountain on which it formed. Here, Hameed notes, is the island of Kandholhudoo, whose residents experienced chronic flooding whenever high tides coincided with heavy monsoon rains. The last straw was the tsunami, which rendered all but eight of some 500 homes uninhabitable. Now, at the request of village leaders, the government is drawing up plans to move everyone to Dhuvaafaru, an uninhabited island about 12 miles away.

First, though, Dhuvaafaru will be given a revetment-reinforced beach bordered by trees and shrubs, and key areas near the center will be raised with landfill. On top of these artificial high points, public buildings--such as a school, a clinic, a mosque--will add a further vertical dimension, creating what government officials refer to as a "safe island," or at least a safer one. "Certainly we will leave the Maldives if we have to," says Amjad Abdulla, deputy director of strategic policy in the Ministry of Environment and Construction, "but we'd like to stay if we can."

Before leaving Male, I walk clear around the island, stopping at the monument to the tetrapods, the name given to the interlocking concrete blocks that form the towering breakwaters protecting the city's most vulnerable flanks. Behind the breakwaters I hear the crash of invisible waves, in front the laughter of children swimming in the intensely blue water of a narrow canal. I wonder, What will the Maldives be like a couple of centuries from now? Will its corals have adapted to warmer conditions, as some think possible, or will they be forced to seek refuge in artificially maintained reefs? And what of its people, now spread out across 200 islands? Will they retreat to a few fortified strongholds and learn to live, as the Dutch have, behind high walls that cut them off from the sea? It's not as dramatic a fate as being overrun by a rising tide, perhaps, but in its own way it's just as chilling. o