Study Envisions Rising Sea Levels, Disaster

Rising sea levels over the next 50 years could swamp hotels, power plants, the Point Mugu military base and as many as 4,100 low-lying houses along the Ventura County coastline during big storms, according to a new study of global warming by a USC research team.

“Coastal residents would lose the use, perhaps permanently, of roads, structures, power lines, railroads, recreational facilities, trailer parks and camping areas,” said environmental sociologist Angela Constable, lead author of the report.

Researchers, who studied Ventura County as a model for California’s coastal communities, said they expect a sea-level rise of about 2 feet by 2040, and that local governments’ reaction to the threats of sea rise and beach erosion will determine how much damage actually occurs.

The USC team concluded that governments could offset much of the potential damage by responding in a variety of ways, including stricter building standards, higher sand berms on beaches and construction of rock groins and underwater breaks in the ocean to alter wave action and erosion.

Unless new coastal homes in Ventura County are built on stilts, such as those supporting houses in storm-battered Florida and South Carolina, million-dollar beachfront dwellings could be ruined, the study concluded. The city of Oxnard, in fact, already requires new beach houses to be elevated about 3 feet above the ground.

“This is not an overnight scenario,” said Constable, a doctoral candidate at USC and a lecturer at Cal Lutheran University in Thousand Oaks. “You don’t wake up one morning and the sea has risen. And we assume that Ventura County and other coastal areas will provide mitigations. But without them, you would lose all of those homes.”

Along the Ventura County coast, the researchers say the shoreline could recede by 50 to 75 yards over five decades, and during severe storms ocean water could damage structures such as Ventura Pier, Ventura Harbor, Ventura’s sewage plant, two Edison power plants, the Mandalay Beach Resort, Channel Islands Harbor and a portion of the Naval Air Weapons Station at Point Mugu.

Flooding could occur in houses within a block of the shoreline--including streets in beach communities such as Ventura’s Pierpont Bay, Oxnard Shores, Hollywood Beach, Silver Strand and Surfside in Port Hueneme, the researchers concluded.

Using estimates of a 2-foot sea rise--considered by the researchers as the most likely scenario based on global-warming studies by a United Nations task force--houses for 9,100 people could be damaged during storms, Constable said.

Researchers also evaluated the effects of a 10-foot ocean rise, which they consider highly unlikely but possible during large storms, and found that the homes of 40,000 residents would be at risk.

But that is without local governments responding to what many scientists believe are the effects of global warming--higher seas and a pattern of more severe storms, the researchers said.

There is broad agreement among scientists that the Earth has become warmer by an average of more than one degree during the past century. And many scientists attribute the cause to global warming--a hypothetical change in climate caused by carbon dioxide and other gases from autos and industry that trap warm air in the atmosphere and create a greenhouse effect.

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Numerous studies have found that sea levels are rising. For instance, scientists at the Scripps Institution of Oceanography at UC San Diego found in 1992 that the sea level off Southern California was rising about an inch a decade, because ocean water expands as it warms. Some scientists also suspect the warming has already begun to melt glaciers, which would raise sea levels.

While global warming has not been proven, Richard Somerville, who studies the greenhouse theory at the Scripps Institution, said the USC projection of a 2-foot sea rise is “in the ballpark.”

Said Somerville: “Whether it’s 2 feet, or 1 foot or 3 feet, it’s clearly the consequence of global warming.”

The degree to which global warming could raise sea levels has been a subject of intense scientific debate for at least a decade, and the USC researchers caution that recent studies have scaled back early projections.

For instance, the Intergovernmental Panel on Climate Change, a United Nations task force of 2,500 scientists, had considered 26 inches as the most likely sea-level rise from a two- to five-degree increase in the Earth’s atmosphere by 2100. But last year the panel reduced its projection to 20 inches.

The USC study, which uses a 24-inch rise in its most likely scenario, is still pertinent because it couples the projected sea rise with the effects of shoreline retreat resulting from coastal development and natural wave action, said USC geographer Douglas J. Sherman, co-author of the study.

“There are still very good reasons for concern, but the sense of almost panic is gone,” Sherman said. “It all depends on whether you’re an optimist or a pessimist. If you’re an optimist, you can assume this will never affect you in your lifetime. If you’re a pessimist, you probably should get some flood insurance.”

Karl Nordstrom, who analyzes oceanfront development practices at the Institute of Marine and Coastal Sciences at Rutgers University, said the 2-foot rise is a conservative estimate.

“I don’t think you should go much below that with estimates, because if you do everything you plan in response will be under-designed,” he said. “But it’s pretty elusive trying to get a hold on precisely what the sea-level rise is going to be. . . . We should concentrate on what should be done about it.”

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In Ventura County, the USC team concluded that remedies should include wider setbacks from the ocean for new construction.

“The ocean can wash through your living room,” Sherman said. “The coastline is prone to flooding similar to what happened in Malibu in 1982-83. . . . And in the Redondo Beach storms of ’87 or ‘88, we had water running off the beach and into the streets.”

Although it is unusual for ocean water to wash into Ventura County streets, Oxnard city officials acknowledge it happens occasionally in Oxnard Shores, where years ago an old cottage owned by Sonny Bono and Cher and other houses were flooded by seawater.

In perfect weather, high tide can peak just 25 feet from houses near Seaward Avenue in Ventura, Constable said. Even without higher sea levels, storms have toppled piers in Ventura and Port Hueneme, and severe beach erosion threatened a roadway and condominiums in Port Hueneme last year. Parts of an oceanfront bike path at the county fairgrounds in Ventura are closed because of wave damage.

“And it’s just going to get worse,” Sherman added. “Flooding may not happen this winter or in five winters or 10 winters, but without human intervention it will happen.”

The USC team’s findings--based on decades of storm, wave and beach-erosion data--are scheduled to be published in the March issue of World Resources Review, a scholarly journal of environmental research.

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The study is significant, the quarterly publication’s editor said, because analyses of global warming rarely spotlight local effects. And studies that do usually concern wetlands and wildlife, not land-use at shoreline.

“We always want to see what is going to happen in our own backyard, and that is what this study has done for California,” said Sinyan Shen, director of the Global Warming International Center near Chicago.

The new study focused on Ventura County because so much of the Oxnard Plain is near sea level. “We expected the effect to be particularly severe there, because the shoreline is flat and beach erosion is already a problem,” said Maurice D. Van Arsdol, a USC demographer.

Still, researchers figured that whatever effects global warming had there would have implications for the state’s other coastal counties, where populations are expected to double over the next 50 years.

Officials in Ventura County who already deal with ocean-related problems reacted to the USC study with a mix of acceptance and skepticism.

“There may be something that needs to be done in terms of recognizing that the ocean is rising,” county Public Works Director Art Goulet said. “But it may be that local government is not yet aware that there is a potential problem out there.”

In Port Hueneme, City Manager Richard Velthoen said his city is already dealing with problems of severe beach erosion.

The ocean crawled to within a few feet of a condo-lined city street last year before a multimillion-dollar federal project restored the beach with about 2 million cubic feet of sand.

And, because cities are so strapped for money, it will take state and federal grants to follow through on many of the fixes suggested in the USC report, Velthoen said.

“If the sea rises, our problems just get worse,” he said. “It makes me want to move to Ojai.”

Erosion alone could cut 150 feet off Ventura County’s shoreline over 50 years, the USC study said.

But Oxnard coastal planner Deanna Walsh said erosion problems have only been seasonal on her city’s beaches: The sand that has washed away in the winter has come back in the summer.

“Before I came 14 years ago, some houses were flooded,” she said. But city codes implemented in 1992 required that new beachfront homes be elevated on concrete pilings about 3 feet above the beach, and a foot above the projected maximum wave crests in the worst storms.

Now, homeowners such as JoAnn Linder live in new houses above the sand. But that doesn’t mean they take seriously the threat of a rising sea.

“Hogwash. They’re mistaken big time,” Linder told researcher Constable during an oceanfront talk last week. “I’ve lived on the ocean for 67 years. There is always beach erosion, and it always comes back.” The real problem is not global warming, Linder said, it’s bad drainage.

Constable said Linder’s reaction is typical.

“People aren’t really going to see the importance of global warming. They aren’t going to see the sea rising,” she said. “They’re going to point to a local explanation of a problem, not to a global phenomenon.”

(BEGIN TEXT OF INFOBOX / INFOGRAPHIC)

A two-foot rise in the ocean level over the next five decades could flood the county coastline during large storms, researchers predict.

1. Pierpoint Bay

2. Ventura Harbor

3. Edison Power Plant

4. Oxnard Shores

5. Hollywood Beach

6. Channel Islands Harbor

7. Silver Strand

8. Port of Hueneme

9. Hueneme Beach

10. Ormond Beach

11. Point Mugu