More extreme weather, droughts, flooding and rising sea levels, decreased farm yields and heat-related health problems - that's what a congressionally mandated assessment of climate change produced by U.S. scientists says people in the South can expect in the coming decades.

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The National Climate Assessment: ncadac. globalchange.gov.

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Those already concerned about climate change quickly embraced the 840-page National Climate Assessment as an important wake-up call. Conservative groups and some Republican lawmakers just as quickly declared the report "laughably misleading" and alarmist.

The National Climate Assessment says that in addition to warmer average temperatures and rising sea levels, climate change means that unusual and extreme weather patterns are expected to become more frequent.

That doesn't mean specific weather events, such as the unusual ice storms that twice closed the Ravenel Bridge between Charleston and Mount Pleasant this winter, are due to climate change. But it does mean that unusually or extreme weather events in general could become more frequent.

White House science adviser John Holdren called the report released Tuesday "the loudest and clearest alarm bell to date signaling the need to take urgent action." Later this summer, the Obama administration plans to propose new and controversial regulations restricting gases that come from existing coal-fired power plants, following a Supreme Court victory on the issue in late April.

Some South Carolina residents could see higher utility bills as a result, the utility SCE&G said in its parent company SCANA's 2013 annual report. The report said that complying with new requirements to reduce greenhouse gas emissions "may impose significant costs on us, and the resulting price increases to our customers may lower customer consumption."

Emily Brady, a public affairs officer for SCANA, said Tuesday that SCE&G expects to greatly reduce its fossil fuel emissions through the use of more nuclear power.

"With the addition of two new nuclear units, SCE&G is on track to lower carbon emissions by approximately 59 percent from 2005," she said.

Senate Republican leader Mitch McConnell of Kentucky said President Barack Obama was likely to "use the platform to renew his call for a national energy tax. And I'm sure he'll get loud cheers from liberal elites - from the kind of people who leave a giant carbon footprint and then lecture everybody else about low-flow toilets."

Some current and former Republican lawmakers from South Carolina say that climate change does pose a threat, but that more regulations aren't the solution.

"The assessment that came out today is another reminder that climate change is going to present real challenges for the Lowcountry, and the nation as a whole," said U.S. Rep. Mark Sanford, South Carolina's former governor. "I've watched rising sea levels play out at our family farm in Beaufort over the last 50 years, and I think others in our area could also point to impacts they've seen.

"As Congress confronts these challenges, I think we should be searching for solutions that embrace free market principles, rather than increasing already burdensome government regulations," he said.

Bob Inglis was a Republican congressman representing the Greenville and Spartanburg area until 2011, when he lost re-election largely because he called for action on climate change. Now, he runs Energy and Enterprise Initiative, which aims to convince young conservatives to support a tax on fossil fuels that would be offset by reductions in other federal taxes.

"It's so consistent with what we conservatives believe," Inglis said. "We don't want the federal government putting their thumb on the scale, for one fuel or another."

He said the current system, with subsidies for some fuel sources and no tax on emissions produced by fuels, is "socializing a lot of soot and allowing emitters to evade accountability."

Political climate change

South Carolina is deep red, politically, and few state and federal lawmakers have shown interest in climate change. Inglis' organization is doing most of its outreach work in other states, as a result, though he works out of his home in Traveler's Rest.

Inglis predicted that if South Carolina residents eventually push for action on climate change, that push will come from the coast, where rising sea levels and stronger hurricanes are a big concern.

At the The South Carolina Sea Grant Consortium, Liz Fly, coastal climate extension specialist, said they are focusing on working with local communities to discuss how to prepare for the expected changes.

"The release of this (study) is providing us with the opportunity to continue the conversation at the local level on resiliency and adaptation," she said.

Scientists and the White House called the National Climate Assessment the most detailed and U.S.-focused scientific report on global warming yet.

"Climate change, once considered an issue for a distant future, has moved firmly into the present," the report says. "Corn producers in Iowa, oyster growers in Washington state and maple syrup producers in Vermont are all observing climate-related changes that are outside of recent experience."

A look at the report

The report includes 3,096 footnotes to other mostly peer-reviewed research. It was written by more than 250 scientists and government officials, starting in 2012. A draft was released in January 2013, but this version has been reviewed by more scientists, including twice by the National Academy of Science which called it "reasonable."

The Heartland Institute, which is holding a July conference in Las Vegas to explain "the real costs and futility of trying to stop global warming," said the national report was written by hard-core environmental activists.

"It would take a whole squadron of environmental activists years to come up with the whoppers told in this report," said James Taylor, Senior Fellow for Environmental Policy at the free-market think tank. "The report falsely asserts that global warming is causing more extreme weather events, more droughts, more record high temperatures, more wildfires, warmer winters, etc., when each and every one of these false assertions is contradicted by objective, verifiable evidence."

Environmental groups praised the report.

"If we don't slam the brakes on the carbon pollution driving climate change, we're dooming ourselves and our children to more intense heat waves, destructive floods and storms and surging sea levels," said Frances Beinecke, president of the Natural Resources Defense Council.

S.C. Small Business Chamber of Commerce President & CEO Frank Knapp Jr. said the state needs to be planning for the impacts of climate change, particularly in coastal areas with rising sea levels.

"This is just more evidence that we have got to start moving on this thing," Knapp said. "What we hope is that the public is starting to pay attention now and saying, 'Oh, this could be a problem in my lifetime.' "

In a White House conference call with reporters, National Climatic Data Center Director Tom Karl said his two biggest concerns were flooding from sea level rise on the U.S. coastlines - especially for the low-lying cities of Miami, Norfolk, Virginia, and Portsmouth, New Hampshire - and drought, heat waves and prolonged fire seasons in the Southwest.

Weather changes

Even though the nation's average temperature has risen by as much as 1.9 degrees since record keeping began in 1895, it's in the big, wild weather where the average person feels climate change the most, said co-author Katharine Hayhoe, a Texas Tech University climate scientist. Extreme weather like droughts, storms and heat waves hit us in the pocketbooks and can be seen by our own eyes, she said.

Since January 2010, 43 of the lower 48 states have set at least one monthly record for heat, such as California having its warmest January on record this year. In the past 51 months, states have set 80 monthly records for heat, 33 records for being too wet, 12 for lack of rain and just three for cold, according to an Associated Press analysis of federal weather records.

In Charleston, heat records were set in June 2012 at the Charleston Airport, and in March 2012 in downtown Charleston, according to the National Weather Service.

"For the second warmest I have several in 2011 and 2012," said National Weather Service meteorologist Julie Packett.

No record cold months have occurred since January 2010.

The National Climate Assessment says "climate change threatens human health and well-being in many ways." Those include smoke-filled air from wildfires, smoggy air from pollution, and more diseases from tainted food, water, mosquitoes and ticks. And ragweed pollen season has lengthened.

Flooding alone may cost $325 billion by the year 2100 in one of the worst-case scenarios, with $130 billion of that in Florida, the report says. Already the droughts and heat waves of 2011 and 2012 added about $10 billion to farm costs, the report says.

Post and Courier reporter Brenda Rindge and The Associated Press contributed to this report. Reach David Slade at 937-5552.