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THE CASE OF THE VANISHING ISLANDS


Marsh grass and fiddler crab holes fill some of the front yards. Other yards have become mud flats, and hip boots may be required to navigate Main Street during twice-monthly high tides. Nevertheless, some 450 hardy souls stubbornly cling to a way of life on Maryland's Smith Island.


Eye in the Sky


Residents of this remote speck of land in the Chesapeake Bay, first inhabited by English colonists in the 17th century, still speak a brogue that they trace back to Elizabethan times. But the island seems about to join others that already have sunk beneath the waves—a microcosm, say scientists, of the effects of rising sea levels around the world.

"The people of Smith Island are out of time," said Florida International University's Stephen P. Leatherman, who has extensively studied coastal erosion. "I wish it were otherwise, but I don't see any answer for them. Many will hold out for as long as they can, but the next time a really big hurricane comes through, I think that'll be it. Their heritage is slipping away under the sea."

Debate continues over the cause of rising sea levels, especially concerning the effects of fossil fuel-burning, which theoretically promotes global warming by increasing the amount of greenhouse gasses in the atmosphere.

FACING EXTINCTION

But whatever the reason, the unmistakable fact is that the sea is gobbling up dry land at an alarming rate in many parts of the world. Entire nations, including the low-lying Maldives in the Indian Ocean and Vanuatu in the southwest Pacific, face extinction. If current trends continue, the major coastal cities of the world also could be at risk.

"What's going on in the Chesapeake Bay is going on worldwide," said Duncan M. Fitzgerald, a Boston University geologist. "I don't think people understand that an increase in the rate of rise of sea level is going to have a devastating, cataclysmic effect."

Nowhere is the phenomenon more striking than in the Chesapeake Bay—a 193-mile (311-kilometer) inlet of the Atlantic Ocean that lies along the shores of Maryland and Virginia.

"Our best estimate at present is that perhaps an area the size of Washington, D.C. is being lost in the Chesapeake Bay every century now," said Michael S. Kearney of the University of Maryland.

"The water is probably rising somewhere between 30 and 40 centimeters per century, a little more than a foot and a half. Considering that I looked at long-term trends for the last thousand years, it's a six-fold increase. That's a big deal."

Kearney's studies of historical records, along with such indicators as pollens found in sediment samples, show that islands in the bay were slowly eroding from the colonial period until around 1850, when the rate of land loss took a sudden and dramatic upturn. The 1850s period is generally recognized as the beginning of the industrial revolution, with its massive use of coal and oil to power manufacturing plants.

"A lot of islands that had been lived on for several centuries were abandoned in the period between 1920 and 1940," said Kearney. "All of a sudden these communities disappeared, a lot of them lost altogether, the famous example being Sharps Island."

THE FORMER SHARPS ISLAND

Around the beginning of the 19th century, Sharps Island was a roughly 600-acre (240-hectare) farming and fishing community at the mouth of Maryland's Choptank River. At one time it boasted schools, a post office and a popular resort hotel, where vacationers from Baltimore and other locations would arrive by boat to while away the lazy summer days. But between 1850 and 1900, the island lost 80 percent of its land mass, and by 1960 it had been reduced to a shoal. Today it is entirely underwater, marked only by a partly submerged lighthouse.

"A lot of history has been lost," said Kearney. "Some of these islands were plantations. We tried to find an old graveyard that was marked on survey maps of James Island as late as the 1930s. Apparently it's gone in the drink."

Other islands that either have been deserted or have disappeared altogether are Poplar, Barren, Hambleton, Royston, Cows, Punch, Herring, Powell, Swan, and Turtle Egg.

Scientists attribute these losses to a combination of factors, including global warming-possibly accelerated by human activity. Another well-documented cause is the withdrawal of groundwater for agricultural and other uses, resulting in the land essentially falling in on itself.

Additional sinking could be caused by the sheer volume of sediments being dumped into the bay by runoff from farmland and housing developments throughout the watershed. This load may be weighing down the earth's mantle, allowing more water to come in.

ISLANDERS HANG ON

One potentially good result from all this loss of dry land is the creation of salt marshes, which not only provide vital habitat for wildlife but also help filter out some of the fertilizers and other toxins from the runoff. The north end of Smith Island, once farmland, is now a marshy refuge. However, scientists fear that the rate of sea-level rise now is so great that the newly formed marshes themselves will be quickly overwhelmed.

Kearney said his data indicate that within 10 to 20 years, if present trends continue, "we could lose about 70 percent of all coastal marshes in the Chesapeake Bay."

Despite all, Smith Islanders continue to hang on. The U.S. Army Corps of Engineers this week began a U.S. $2 million project to erect bulkheads to protect homes in Tylerton, one of the three small towns on the island. Somerset County tourism officials estimate that between 30,000 and 50,000 visitors come by boat every year to witness the sights and sounds of an endangered way of life.

Jennings Evans, a 69-year-old retired waterman who is the island's unofficial historian, agreed that the long-term outlook is not good for his place of birth.

"They say we're sinking from within, and I can see that," said Evans. "When Hurricane Floyd came in from the northwest last year, people were getting a little bit concerned. The water came right up to the doorstep of one fellow in the town of Ewell. He said he was getting scared."

But Evans, who despite health concerns still occasionally sets out on a workboat to gather crabs, added: "People here aren't going to leave. They say the Lord's looking out for them. I'll be buried here if I don't get drowned at sea."

Eye in the Sky is a weekly series that brings you the story behind the headlines using satellite imagery, remote sensing, aerial photography, and maps. This feature is developed by National Geographic News with the sponsorship of the National Imagery and Mapping Agency (NIMA) and Earth-Info. Check out maps and imagery at http://www.earth-info.org.



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More Information
• Seawater in the Chesapeake Bay—one of the world's largest estuaries—has risen about a foot in the last century, drowning a number of once inhabited islands.
• St. Clements Island has lost about 90 percent of the 400 acres of forestland that Maryland's earliest English colonists first beheld in 1634.
• The Chesapeake Bay itself was formed when ice sheets began melting at the end of the last ice age 10,000 years ago, raising worldwide sea levels. But the rate has increased dramatically since the beginning of the industrial revolution.
• Recent efforts to stem the tide on Smith Island—such as positioning plastic tubes filled with sand and sediment in front of shorelines—have failed to halt the loss of land.


More Information
OUR LAND FOREVER?

The people of Vanuatu — whose name means "Our Land Forever" — wonder where they will go when their island nation sinks beneath the waves.

Vanuatu — formerly the New Hebrides — is a group of about 80 volcanic islands in the Pacific Ocean. Some lie little more than three feet above sea level.

Slightly larger than Connecticut, the chain has been inhabited for thousands of years by Melanesians. Its 192,000 residents believe their homeland is in imminent danger of drowning because of global warming brought on by the burning of fossil fuels by the world's large industrialized nations. Farther to the north, U.S. military graves from World War II already have gone under on the Marshall Islands, whose airport is regularly inundated.

The United Nations last fall held a special two-day session in which Vanuatu and 45 other members of the Alliance of Small Island States pled with large nations to reduce their industrial emissions to help slow the rising flood.

After the session, the General Assembly adopted a declaration reaffirming its commitments to sustainable development. But the global warming pact developed at a 1997 international conference in Kyoto, Japan, remains unratified by major countries, including the United States.