Next Victim of Warming: The Beaches
by: Cornelia Dean 21 June 2006
NEW SMYRNA BEACH, Fla. — When scientists consider the possible effects of global warming, there is a lot they don't know. But they can say one thing for sure: sea levels will rise.
This rising water will be felt along the artificially maintained beaches of New Jersey, in the vanishing marshes of Louisiana, even on the ocean bluffs of California. According to a 2000 report by the Heinz Center for Science, Economics and the Environment, at least a quarter of the houses within 500 feet of the United States coast may be lost to rising seas by 2060. There were 350,000 of these houses when the report was written, but today there are far more.
"If it is as bad as people are saying, at some point it will be a crisis," said Thomas Tomasello of Tallahassee, Fla., a lawyer who represents many owners of coastal property. But he does not dwell on it. "I cannot deal with sea level rise," he said. "That's such a huge issue."
Though most of the country's ocean beaches are eroding, few coastal jurisdictions consider sea level rise in their coastal planning, and still fewer incorporate the fact that the rise is accelerating. Instead, they are sticking with policies that geologists say may help them in the short term but will be untenable or even destructive in the future.
Florida is a good example. To prepare for hurricane season, which began June 1 and has already brought Tropical Storm Alberto, Floridians were still repairing storm damage from 2005 and even 2004, building or repairing walls to shield beachfront buildings.
Until May 1, when turtle nesting season forced them to stop, they were also pumping hundreds of thousands of cubic yards of sand onto eroded beaches. Florida has relied on this approach for decades, but after the past few storm seasons, there has been an increase in applications for sea wall permits, many from Mr. Tomasello's clients. "If you have a house or a condo that's threatened, it's really the only alternative," he said.
Maintaining eroding beaches with artificial infusions of sand is difficult and costly, and as sea levels rise, it may become economically impractical or even impossible. "The combination of sea walls and rising sea level will accelerate the rate of land loss in front of those sea walls," said Peter Howd, an oceanographer who conducts shoreline research for the United States Geological Survey in St. Petersburg. "So people with a sea wall and a beach in front of it will end up with just a sea wall."
Many people "want to disagree" that global warming is a threat to the coast, said Daniel Trescott, a planner on the staff of the Southwest Florida Regional Planning Council, one of 11 such boards in the state. "But the first place you see these impacts is on the beach."
The council is participating in a federal program to map areas that are vulnerable to rising sea levels, identify crucial infrastructure there and assess how much will probably end up protected by armor. Mr. Trescott said he hoped that the effort would put sea levels "on the radar, to start addressing how we are going to respond to this rise."
Elsewhere, scientists are studying data from ancient sediment formations to predict how the barrier islands that form most of the East and Gulf Coasts will respond to rising seas. "As scientists, and especially as federal agency scientists, it's our responsibility to think long term," said S. Jeffress Williams, a coastal geologist at the United States Geological Survey in Woods Hole, Mass., who is organizing a session on sea level rise at a meeting of coastal scientists next year. "What are the cumulative impacts we can expect over the next 50 to 100 years?"
Dr. Williams pointed to a plan by the Army Corps of Engineers for beach maintenance on the South Shore of Long Island, from Fire Island to Montauk Point. The project relies on historical rates of sea level rise, measured by an array of instruments in many locations, rather than on predictions of future acceleration, said Cliff Jones, a project manager for the corps. That is typical of the corps, he said, "to take advantage of what history has shown, as opposed to what might be predicted."
It is an understandable approach, Dr. Williams said, but "it is going to build up false expectations."
As with climate change and other environmental problems that develop imperceptibly, it is hard for people to see rising sea levels as a threat.
"It's a slow process," Dr. Howd said. "It's not something that is visible right now or next week or a year from now."
And the remedies are not attractive, to say the least. Few coastal residents want to see their towns walled off and surrounded by water. And few want to elevate their houses by 20 feet or more, as flooding experts are beginning to recommend in some coastal areas. The approach favored by many scientists, a gradual retreat from the coast, is a perennial nonstarter among real estate interests and their political allies.
"Socioeconomically, politically, it's an ugly mess," Dr. Howd said.
Since the Industrial Revolution, and particularly in the last 50 years, the burning of fossil fuels has been sending heat-trapping gases into the atmosphere. In the last century, global sea levels have risen by about eight inches.
Some of the rise — scientists argue over how much — is because of natural variation, like changes in atmospheric pressures and winds over the Southern Ocean. But much of it results from warming; as water warms, it expands, occupying more space.
Also, warming melts inland glaciers and ice sheets, sending torrents of fresh water into the oceans. In 2001, the Intergovernmental Panel on Climate Change, convened by the United Nations, said that the rise in sea levels was accelerating. Their mid-range projection for 2100 was a rise of just under 20 inches from a 1990 baseline, partly because of this melting. Evidence reported since then suggests that the rise may be even faster. (If ice sheets on Greenland and Antarctica melt significantly, seas will rise by 20 feet or more, but few scientists expect that to happen in this century.)
Even a rise of one or two feet would allow "the waves, the tides, the storms to impact parts of the beaches and marshes and estuaries that they don't reach right now," Dr. Howd said.
How much depends on the geography of the area. For example, much of Florida is so low that a one-foot rise in sea level would send water 100 feet inland. Dr. Howd, 49, who lives in St. Petersburg, said that is one reason he does not expect to retire there. His house is about 600 feet from the beach, but only about 6 feet above sea level.
Undeveloped beaches and wetlands deal with encroaching seas by shifting to higher elevations inland. The barrier islands migrate, in effect, as storms send sand washing over them from ocean to lagoon. The ocean side erodes, but sand piles up on the back side.
"The beach is attempting to find an elevation at which it can maintain its shape," said Laura J. Moore, a geologist who is working with Dr. Williams at Woods Hole while on sabbatical from Oberlin College.
Dr. Moore is using data on past barrier island migration to predict how coastal barriers will fare as the sea level rise accelerates. For any stretch of coast, she said, the answer depends on a number of factors, including geology, wave patterns and sand supply, whether natural or artificial. But in general, the faster the sea level rises, the faster the barrier islands will have to retreat.
The Problem With Walls
At present rates of sea level rise, Dr. Moore said, the computer model she is using "suggests the barriers can maintain themselves, if they are allowed to migrate." But if a sea wall or other infrastructure is in the way, the island is pinned down. Sand that would wash over is blocked as the island erodes. In time, rising water meets the wall and drowns the beach. Meanwhile, storm waves scour the wall's base and erode the underwater beach slope. "Eventually the sea wall collapses because the situation is so extreme."
Now the island is free to move, but it may be too late, she said. If water continues to rise, the island may just disintegrate.
That is already happening on the islands that form the Outer Banks of North Carolina, according to Stan Riggs and Dorothea V. Ames, geologists at East Carolina University. The islands have been pinned down for 70 years by an artificial dune — a wall, in effect — built during the Depression by the Civilian Conservation Corps.
In their book "Drowning the North Carolina Coast" (North Carolina Sea Grant, 2003), they say perennial washouts of the road connecting the islands show that "large segments of the Outer Banks are already collapsing." If even the 2001 estimates from the United Nations panel are correct, they say, there will be "major land loss."
A recent study led by Michael Oppenheimer, a climate researcher at the Woodrow Wilson School of Public and International Affairs at Princeton, said a sea level rise of two to four feet would be devastating in New Jersey. For example, the study found that Cape May would "attenuate, change in composition and potentially disappear."
What does this mean for people whose houses or businesses are on the beach? "They may be difficult to maintain," Dr. Moore said. "We have to start thinking about that."
Holding the Line
There are those who doubt that things will be so bad. One of them is Robert G. Dean of the University of Florida, one of the nation's leading coastal engineers. Like many coastal scientists, he attributes much of the beach erosion Florida has experienced to coastal inlets, most of them artificial, that interfere with the natural flow of sand. And he does not foresee the kind of sea level rise predicted by the United Nations panel.
If sea levels rise in the 21st century at the same rate they did in the 20th, Dr. Dean said — "and if I had to, I'd bet on that"— his fellow engineers "would be able to hold 99 percent of the Florida shoreline."
If sea levels follow the panel's midrange estimate of a nearly 20-inch rise, "then I'd back off that 99 percent to say 70-80-85 percent," he said.
Finding replacement sand for eroding beaches would be troublesome — it is already hard to find — but, he said, "they will import sand or bring it from inland or maybe manufacture it" by grinding up stone, as he said was done years ago in Monaco. "People will be creative."
Of course, it will be expensive. Many Florida beaches exist now only because they are artificially maintained, and by some estimates at least 20 percent of the state's coast is armored, a percentage certain to rise. Like other states, Florida has setback requirements and other regulations that in theory limit sea wall construction, but owners of buildings in imminent danger are often given emergency permission to protect them. And once walls are in place, they are rarely removed.
The result is ever more stretches of beach that must be artificially replenished. According to Mr. Trescott of the Southwest Florida Regional Planning Council, government agencies have spent "about half a billion dollars" on beach building in Florida since the 2004 hurricane season. That's a bargain, according to many state and local officials, who point out that beaches pump $40 billion or more into Florida's economy each year.
But it is far from clear that replenishing them will be affordable or even possible in an era of rising seas. "You are probably conservatively talking about hundreds of millions of cubic meters of sand, and for the most part that sand is not available," Dr. Williams said. Counting on that approach "is the wrong thing to do unless all that is sorted out," he said.
Even Dr. Dean believes that a rise of three feet or more will mean trouble.
"I don't believe that's going to happen," he said, pointing out that people who study sea level rise "may have somewhat of a vested interest in keeping the project alive." But if it did happen, he conceded, "that would not be good at all."
Waiting for Sand
Volusia County, on the east coast of Florida, was hit hard by the hurricanes of 2004. "In some areas we lost 6 or 7 feet of beach grade, and the dune system cut back in some areas as much as 20 to 25 feet," said Jennifer Winters, who manages turtle habitats for the county.
Repairs began at once, with property owners winning emergency permission to install sandbags, corrugated vinyl bulkheads, sea walls and other devices, and work was still under way this spring.
At East 27th Street Park in New Smyrna Beach, workers replaced a fallen sea wall and filled in behind it. Beginning in January, a pipeline disgorged a slurry of water and sand, dredged from the Ponce de Leon Inlet nearly five miles away, onto the beach. According to David May, an engineer with Subaqueous Services, a dredging contractor based in Orlando that did the work, 743,000 cubic yards of additional sand would be pumped onto a five-mile stretch of beach, at a cost of about $14 million.
People who lived on the beach "kept complaining to me about their property, and I said, 'hold on, sand is coming,' " Ms. Winters recalled recently as she drove a county truck along the beach, passing houses and condominium developments armored with concrete, vinyl sheet piling, piles of rock, sandbags or even wooden planks.
She made the drive at low tide; at high tide the water would reach the walls in many areas, leaving no dry beach. "You cannot even walk the beach at high tide," she said.
That is typical of armored beaches, researchers who study them say, and it is one of the reasons environmentalists worry about the armor-and-fill approach.
In research in Santa Barbara, Calif., that was reported in the winter issue of the journal Shore and Beach, Jenifer E. Dugan and David M. Hubbard of the University of California, Santa Barbara, found that on armored beaches, there was much less accumulation of seaweed and other drift material, far fewer insects and crustaceans that feed on or in this wrack, fewer intertidal species like sand crabs and clams, and fewer species of birds.
Their conclusion? "The combination of rising sea levels predicted by climate change models and the increasing extent of coastal armoring will accelerate beach loss and increase ecological consequences for sandy beach communities and shorebirds in many regions."
The dredging process itself inflicts environmental damage by altering currents, changing the way sand moves in the water or making water murky, according to Ken Lindeman, a senior scientist with the advocacy group Environmental Defense. So-called borrow sites where sand is dredged (Dr. Lindeman calls them underwater "craters") may not recover their plant and animal biodiversity, he said, and little is known about the effects of artificial beach building on habitats near shore, where, he said, "juvenile fish develop before migrating offshore and where the greatest impact of coastal construction is."
"The assumption is made that the fish just swim away," but fish settle in these areas as larvae, he said. "They are not adapted to swimming away."
Dr. Lindeman pointed out that advocates for anglers were beginning to talk about these problems. And surfers are starting to speak up when dredging projects threaten to disrupt wave patterns they favor. "Surfers, divers, fishermen are trying to get answers to excellent questions," he said.
Does the Government Know?
James Titus, an Environmental Protection Agency project manager for sea level rise who is leading an agency mapping effort, wrote an essay for a law review a few years ago in which he argued that the nation needed to make decisions on whether or how wetlands and beaches should be allowed to migrate inland. Otherwise, he wrote, government policy is saying, in effect, that "wetlands and beaches are important resources that must be preserved for the duration of this generation, but whether they survive for the next 50 to 100 years is not our problem."
Mr. Titus titled his essay, published in the Golden Gate Law Review in 2000, "Does the U.S. Government Realize That the Sea Is Rising?" It was accompanied by a disclaimer noting that it did not represent the views of the E.P.A.
Reached by telephone, Mr. Titus said he was no longer allowed to discuss such issues publicly and referred questions to the agency's press office, which would not allow him to speak about it on the record. Instead, requests for on-the-record information were referred to Bill Wehrum, the agency's acting assistant administrator for air and radiation.
"The administration's strategy for dealing with climate change is to continue to put significant resources into understanding climate change," Mr. Wehrum said. "The goal is to develop information that will be useful for local planners. This is about looking at coastal areas and assessing how those areas are used and then helping people with the question of how much protection they might want to provide for those areas if sea level continues to rise."
In general, Mr. Wehrum said, it seemed quite likely that people would want to protect developed areas and might be willing to let undeveloped areas like wildlife refuges or coastal farms migrate.
Meanwhile, though, people like Ms. Winters and Dr. Williams watch as, one by one, people make decisions that will collectively have big implications for beaches.
"The levee failures and flooding of Katrina were no surprise to geologists who studied the area," Dr. Williams said, and damage from future coastal storms will not surprise them either. But he said, "I don't think we have the political will at the administration level" to confront the issue.
"We're rebuilding bigger and better," Dr. Williams said. "We see that in every storm."