IMAGE: GREENLAND COASTLINE
Michael Kappeler  /  AP
A ship passes by the coast of Greenland where the nearby Sermeq Kujalleq glacier, a U.N. heritage site, has thinned in recent years. Greenland experts are surprised by the rapid retreat of ice along the continent, which would raise sea levels by 20 feet if all the ice on it completely melted.
updated 9/24/2007 9:36:30 AM ET 2007-09-24T13:36:30

Rising seas will ultimately swamp the first American settlement in Jamestown, Va., as well as the Florida launch pad that sent the first American into orbit, many climate scientists are predicting.

As they see it, it's just a matter of time.

Few of the more than two dozen climate experts interviewed disagree with the U.N. projection last February that levels will rise by three feet, or a meter. Some believe it could happen in 50 years, others say 100, and still others say 150.

“We’re going to get a meter and there’s nothing we can do about it,” said climatologist Andrew Weaver of Canada's University of Victoria, a lead author of the February report from the Intergovernmental Panel on Climate Change. “It’s going to happen no matter what — the question is when.”

So, in about a century, many places that make America what it is might be slowly erased by seas rising due to melting glaciers, disappearing ice sheets and waters that literally expand because of warming.

In this scenario, rising seas will lap at the foundations of old money Wall Street and the new money towers of Silicon Valley. They will swamp big city airports and major interstate highways.

Storm surges worsened by sea level rise will flood the waterfront getaways of rich politicians — the Bushes’ Kennebunkport and John Edwards’ place on the Outer Banks. And gone will be many of the beaches in Texas and Florida favored by budget-conscious students on Spring Break.

The specific, and troubling, outlook is projected in coastal maps created by scientists at the University of Arizona and which are based on data from the U.S. Geological Survey.

What to protect?
Sea level rise “has consequences about where people live and what they care about,” said Donald Boesch, a University of Maryland scientist who has studied the issue. “We’re going to be into this big national debate about what we protect and at what cost.”

This week, beginning with a meeting at the United Nations on Monday, world leaders are convening to talk about fighting global warming. At week’s end, leaders will gather in Washington with President Bush.

Rising seasExperts say that protecting America’s coastlines would run well into the billions and not all spots could be saved.

And it’s not just a rising ocean that is the problem. With it comes an even greater danger of storm surge, from hurricanes, winter storms and regular coastal storms, Boesch said. Sea level rise means higher and more frequent flooding from these extreme events, he said.

All told, three feet of sea level rise in just the lower 48 states would put about 25,000 square miles under water, according to Jonathan Overpeck, director of the Institute for the Study of Planet Earth at the University of Arizona. That’s an area the size of West Virginia.

The amount of lost land is even greater when Hawaii and Alaska are included, said Overpeck, who is one of the scientists mapping coastal scenarios.

The Environmental Protection Agency’s calculation projects a land loss of about 22,000 square miles. The EPA, which studied only the Eastern and Gulf coasts, found that Louisiana, Florida, North Carolina, Texas and South Carolina would lose the most land. But even inland areas like Pennsylvania and the District of Columbia also have slivers of at-risk land, according to the EPA.

Recent past as clues
This past summer’s flooding of subways in New York could become far more regular, even an everyday occurrence, with the projected sea rise, other scientists said. And New Orleans’ Katrina experience and the daily loss of Louisiana wetlands — which serve as a barrier that weakens hurricanes — are previews of what’s to come there.

Florida faces a serious public health risk from rising salt water tainting drinking water wells, said Joel Scheraga, the EPA’s director of global change research. And the farm-rich San Joaquin Delta in California faces serious salt water flooding problems, other experts said.

“Sea level rise is going to have more general impact to the population and the infrastructure than almost anything else that I can think of,” said S. Jeffress Williams, a U.S. Geological Survey coastal geologist in Woods Hole, Mass.

Even John Christy at the University of Alabama in Huntsville, a scientist often quoted by global warming skeptics, said he figures the seas will rise at least 16 inches by the end of the century. But he tells people to prepare for a rise of about three feet just in case.

Williams says it’s “not unreasonable at all” to expect that much in 100 years given that seas have risen by about eight inches in the last century.

The change will be a gradual process, one that is so slow it will be easy to ignore for a while.

“It’s like sticking your finger in a pot of water on a burner and you turn the heat on, Williams said. “You kind of get used to it.”

Coastal strategies
Susanne Moser of the National Center for Atmospheric Research has studied the sea rise problem and says it may actually be cheaper to try to slow global warming by cutting fossil fuel emissions.

But, assuming that doesn't happen, there are three primary ways for coastal areas to survive the rising seas predicted with global warming. None is perfect. None is cheap.

The first option is to retreat. Abandon the low-lying area to the oncoming sea and build farther inland. Think parts of the disappearing Louisiana coastline.

But some properties along the coasts are so valuable — tens of trillions of dollars in value in Florida alone — and involve so much infrastructure that they can’t be abandoned. Think New York City or Miami.

So in those areas, artificial protection could be devised through earthen levees and dikes. Or there could be costly high-tech solutions. The Netherlands, which is mostly at or below sea level, has the world’s largest flood control system with an intricate system of barriers, levees, sluices, pumps and a gigantic swinging sea gate. The cost over 40 years was about $18 billion to protect a country the size of Maryland.

The cost would be prohibitive to protect all U.S. coastal regions, and such efforts would change some wetlands into freshwater lakes.

The third option is to raise the elevation of buildings and land on the coast. This, too, is expensive and requires constant battles against the elements. Think parts of the Outer Banks. There, some houses are on stilts, and beach replenishing occurs regularly.

One state, Maine, requires developers to anticipate the future. It has a regulation that demands that sea level rise be considered before permits are issued for new large buildings. That rule has blocked construction of some high-rises.

© 2013 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

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