RALEIGH, N.C. — When scientists at a state commission predicted that North Carolina’s sea levels could rise 39 inches by 2100, coastal business and development leaders weren’t alarmed at the prospect of flooding. They were outraged by the report itself.

They complained to state legislators, saying the projection could trigger regulations costing coastal businesses and homeowners millions of dollars.

The result is House Bill 819, a measure that would require sea level forecasts to be based on past patterns and would all but outlaw projections based on climate change data.

The bill, now under discussion by a legislative conference committee, has been ridiculed nationwide. It was mocked by comedian Stephen Colbert and savaged in a Scientific American blog post titled “N.C. Considers Making Sea Rise Illegal.”

It has also focused attention on the political shift in North Carolina, where Republicans in 2010 won control of the state Legislature for the first time in a century.

The legislation would outlaw “scenarios of accelerated rates of sea level rise unless such rates are from statistically significant, peer-reviewed data and are consistent with historic trends.”

Scientists and environmentalists say the bill would legislate science and inhibit research. Orrin H. Pilkey, a geology professor emeritus at Duke University, said making projections based only on past sea level changes is like limiting hurricane warnings to the precise spots where hurricanes have struck.

Stanley R. Riggs, an East Carolina University geologist and one of 19 scientists who made the 39-inch projection, said the bill represents “a criminally serious disregard for science.”

The Science Panel on Coastal Hazards of the state Coastal Resources Commission consists of marine scientists, geologists and engineers who relied on tide gauges, satellite altimetry, storm records and geologic data. They cautioned that predicting long-term sea level change is “an inexact exact science,” saying the report reflects “the likely range” of sea level rise due to global warming and the melting of ice shelves.

Because sea levels and scientific knowledge are advancing rapidly, Riggs said in an interview, the panel recommended recalculating sea level projections every five years.

The bill’s backers issued their own projections, using data from tide gauges and carbon dioxide levels, and citing studies that project no or minimal sea level rise. They predict a rise of, at the most, 8 inches — and contend that sea levels are actually receding in some coastal areas. They say the 39-inch projection would restrict economic development, send insurance rates skyrocketing and decrease coastal property values.

“It’s a death sentence for coastal North Carolina,” said Tom Thompson, who leads the coastal business group, known as NC-20 for its representation of 20 coastal counties. “It could quite frankly kill development on the coast.”

Thompson, director of the Beaufort County Economic Development Commission, called the 39-inch prediction “dishonest statistically” and no better than a coin flip. In an interview, he dismissed climate change as “a phobia” pushed by environmentalists.

John Droz Jr., NC-20’s science advisor, said commission scientists were “bent on promoting their personal political agenda.” NC-20’s projections “are entirely about the science” and have nothing to do with developers, or economics, Droz wrote in a letter to the News & Observer newspaper.

Republican state Sen. David Rouzer, a sponsor of the bill, did not respond to requests for comment. After the measure was endorsed by a state Senate committee June 7, Rouzer told reporters:

“If you’re going to use science when you really can’t validate it … you’re going to be implementing policy and rules and regulations that can have a very, very negative impact on the coastal economy of this state.”

A spokeswoman for Gov. Bev Perdue, a Democrat, said the governor would not announce her position on the bill unless it was passed by the Legislature.

Biology professor Robert B. Jackson, who directs Duke University’s Center on Global Change, warned a Senate committee earlier this month that denying rising sea levels puts coastal residents and property at risk of serious flooding.

“There are many things we can do something about if we use this data,” Jackson said. “I don’t see why taking into account the range of possible futures costs us money, compared to naively assuming the best-case scenario.”

Riggs, the geologist, said the panel had preferred to report a range of projected sea level rises — from 15 to 18 inches to 55 inches, based on each member’s projections. But because the commission demanded an absolute number, the panel took the mean of the range, or 39 inches.

Comedian Colbert brought the debate to a national audience, wisecracking in a segment titled “Sea, No Evil” on the June 4 “Colbert Report”: “If your science gives you a result you don’t like, pass a law saying the result is illegal. Problem solved.”

The bill has triggered lively debate on social media, websites and the letters page of the News & Observer. The paper’s editorial board called the bill “a burst of legislative folly.”

One letter, titled “Sea-Level Fiction,” said the bill “reveals just how far the climate change-deniers and their anti-environmental, science-hating minions have penetrated” state government. Another, from an environmental technology professor at North Carolina State University, said: “We are the laughingstock of the nation.”

In a recent full-page newspaper ad titled “The N.C. General Assembly wants to ignore science,” the Southern Environmental Law Center said the sea level bill would “set a dangerous precedent of politicians telling scientists what data they may and may not use.”

david.zucchino@latimes.com