The dangers of climate change were revealed to Willo Kelly in a government conference room in the summer of 2011. By the end of the century, state officials said, the ocean would be 39 inches higher and her home on the Outer Banks would be swamped.

The state had detailed maps to illustrate this claim and was developing a Web site where people could check by street address to see if their property was doomed. There was no talk of salvation, no plan to hold back the tide. The 39-inch forecast was “a death sentence,” Kelly said, “for ever trying to sell your house.”

So Kelly, a lobbyist for Realtors and home builders on the Outer Banks, resolved to prove the forecast wrong. And thus began one of the nation’s most notorious battles over climate change.

Coastal residents joined forces with climate skeptics to attack the science of global warming and persuade North Carolina’s Republican-controlled legislature to deep-six the 39-inch projection, which had been advanced under the outgoing Democratic governor. Now, the state is working on a new forecast that will look only 30 years out and therefore show the seas rising by no more than eight inches.

Environmentalists are appalled, and North Carolina has been lampooned as a hotbed of greedy developers trying to “outlaw” the rising tide. Some climate-change experts are sympathetic, however, calling the rebellion an understandable reaction to sea-level forecasts that are rapidly becoming both widely available and alarmingly precise.

Rising water in coastal North Carolina

“The main problem they have is fear,” said Michael Orbach, a marine policy professor at Duke University who has met with coastal leaders. “They realize this is going to have a huge impact on the coastal economy and coastal development interests. And, at this point, we don’t actually know what we’re going to do about it.”

Cities such as Norfolk and Miami have embraced the data, identifying inundation zones as a first step toward planning — and seeking federal funds for — sea walls, floodgates and other forms of protection. On lonelier stretches of the U.S. shoreline, however, government aid seems less likely than interference and abandonment, and the forecasts are sparking deep anxiety about the future.

In the Carolinas and Southampton, N.Y., isolated enclaves of ultra-rich shore-front owners have moved preemptively to build private bulkheads to protect their homes from the rising sea. But such fortifications are not an option on the Outer Banks, a string of narrow barrier islands dotted with busy beach towns, isolated fishing villages and stretches of wild seashore. In spots, the islands are barely 100 yards wide.

“We don’t have any tools in our toolbox other than retreat,” Kelly said on a recent morning in a sunny Manteo cafe that would be underwater if the sea were 39 inches higher. “In the backs of their minds, what everyone is thinking is that they just want people off the Outer Banks.”

Long before that would happen, though, Kelly worries that codifying the 39-inch forecast would crush the local economy, which relies entirely on tourism and the construction, sale and rental of family beach houses. In Dare County alone, the islands’ largest jurisdiction, the state has identified more than 8,500 structures, with an assessed value of nearly $1.4 billion, that would be inundated if the tides were 39 inches higher.

Even with an eight-inch forecast, 414 Dare County properties worth $70 million would be marked for inundation. If the state ever activates the Web site that lets potential investors search by address, Kelly said, “all of a sudden, those properties would be worthless.”

Nationwide, $700 billion of coastal property could be below mean sea level by the end of the century — and an additional $730 billion could be at risk at high tide — without new policies to forestall climate change, according to a new report by the Risky Business Project, a high-powered group of financial and political figures who are set to meet Wednesday with senior Obama administration officials.

Some of the biggest West Coast businesses are pushing Congress and state government to act on climate change legislation. But it’s less about global warming and more about their bottom lines. (Pamela Kirkland/The Washington Post)

So far, locals say there is no sign that the housing market on the Outer Banks is suffering. Nags Head’s town manager, Cliff Ogburn, said that the town is doing a booming business in building permits and that “occupancy is as high as it’s ever been,” having rebounded from the dark days before 2011. That is when Nags Head and Dare County spent $36 million to repair severe erosion on 10 miles of beachfront, where encroaching waves had claimed nearly a dozen houses and the seaside swimming pool at the Nags Head Comfort Inn.

Now the beach looks great, the tourists are back and Duck, Kitty Hawk and Kill Devil Hills are talking to the county about beach nourishment projects of their own.

“We lose beach because the water is rising equal to the thickness of two nickels every year,” Bobby Outten, the manager of Dare County, said on a recent tour of the restored shoreline. “Some call it sea-level rise, but from our perspective it’s erosion, and we’ve been living with it forever.”

The arrival of man-made beaches on the Outer Banks has drawn the disapproval of some environmentalists. For generations, the islands have moved with the waves and human settlements have moved with them. These days, however, the islands are so heavily developed, houses threatened by the surf often have nowhere to go.

Beach nourishment offers a temporary solution. But as the sea rises, it “ceases to be cost effective and it becomes obvious that something else has to happen,” said Spencer Rogers, an erosion specialist with North Carolina Sea Grant, a research consortium based at North Carolina State University.

“If things get to the worst extent, then we’re going to be abandoning places,” Rogers said. “There won’t be any option.”

Outten acknowledges that nourishment is a temporary fix, but he argues that it protects property, beautifies the shoreline and keeps the local economy humming. Besides, he said, it’s the only option he’s got.

“What is it you would ask us to do differently right now? Tell people to move away?” Outten said. “Preaching abandonment is absurd. People would go in the closet and get the guns out.”

That’s nearly what happened when local officials caught wind of the 39-inch forecast. The North Carolina Coastal Resources Commission, which regulates land use in the state’s 20 coastal counties, had asked its science panel to assess vulnerability to sea-level rise, which was then becoming a hot topic nationally.

In 2010, the panel reviewed the scientific literature and concluded that the seas along the North Carolina coast could rise anywhere from 15 inches to 55 inches over the coming century, a forecast in line with projections by federal agencies and various other states.

But the science panel took a step further. For planning purposes, it said, the state should figure on 39 inches by 2100. So the commission drafted a policy declaring sea-level rise “a pervasive and persistent hazard” and ordering coastal counties to use the 39-inch forecast for private development and public infrastructure projects.

If adopted, the policy would have made North Carolina the first state to issue such a precise forecast for sea-level rise, said Skip Stiles, who tracks state activity on climate change for Virginia-based Wetlands Watch. Bob Emory, the Coastal Resources Commission’s chairman at the time, said its members “had no idea we were opening up a can of worms.”

The worms hit the fan in January 2011, when the commission rolled out the policy in a closed-door briefing for Carteret County.

“They said there were numerous things the county had to start doing: Raise roads, elevate bridges, rezone land. Any property affected by 39 inches, they wanted to be rezoned as uninhabitable,” said John Droz, a local physicist who was quickly recruited by Carteret County officials to undertake an independent review of the 39-inch forecast.

Emory disputed that account, saying the commission had no intention of demanding such drastic action. “We were not at the stage where there was enough certainty to say you can do this here, you can’t do that there,” he said.

Nonetheless, the Carteret County chairman fired off a letter asking neighboring counties for help “repudiating the proposal.” The science was uncertain, he wrote, there was no assessment of economic impact and there were no maps to show what it all meant.

By July, when Kelly walked into that meeting of federal and state planning officials, the state had maps. And the news was not good.

At 39 inches, the backside of the Outer Banks was gone. So was most of Roanoke Island. Inland, it was worse. On the gentle slope of the piedmont, every foot of sea-level rise would inundate roughly 1,000 acres. Pamlico Sound would look more like the Chesapeake Bay — one of the most profound transformations of coastline predicted anywhere in the country.

Rumors spread, and members of the state’s environmental community fanned the flames, musing publicly about an end to new construction on the Outer Banks and the possible abandonment of Highway 12, the islands’ wave-battered, much-repaired lifeline.

A member of the science panel, geologist Stanley Riggs, published a book likening the islands to a “string of pearls” that would soon be separated by shoals unable to support a fixed highway. In Dare County, this spawned dark jokes about getting to work by kayak.

In 2012, the General Assembly agreed that the state was moving too fast. Lawmakers set aside the 39-inch forecast and ordered the commission to draft new projections that take into account dissenting views on sea-level rise and its causes.

The state’s new Republican governor appointed a new coastal commission chairman, Frank Gorham, an oil and gas man who announced this spring that the new forecast would be limited to 30 years.

With the 100-year forecast, “we just lost credibility,” Gorham said. “If you have a 30-year period, people will take it more seriously.”

Rogers, who has served on the commission’s science panel since its inception, predicts that the new forecast will look pretty much like the old one, which concluded that the sea would rise at roughly historic rates through 2050. Only in the latter half of the century is sea-level rise projected to accelerate sharply. But that lies outside the scope of the new forecast, which is due out next year.

With their bureaucratic victory, coastal leaders are postponing the inevitable, environmentalists say.

“I can see their point. They’re saying, ‘How do we know the sea is going to rise 39 inches in 100 years?’ And the truth is, we don’t. But you’ve got to start planning for something,” said Andrew Coburn, associate director of Western Carolina University’s Program for the Study of Developed Shorelines. “They’re trying to ignore the problem, hoping it will go away.”

Outten, the Dare County manager, says he is not ignoring the forecast, though he does pray it’s wrong.

In the meantime, he said, “it doesn’t seem reasonable to invest today’s tax dollars and punish the public for a problem that is 100 years away and may not exist. We aren’t arguing with science. We’re just trying to be reasonable.”