Global warming is happening. It's caused by human activity, particularly the burning of fossil fuels. And its consequences are severe and unavoidable.

At this point, the best humankind can hope for is to stave off the worst-case scenario while preparing for the changes already underway.

So concluded a report released Friday by the Intergovernmental Panel on Climate Change, created in 1988 by the United Nations and World Meteorological Organization to assess the risk and impact of human-induced climate change. That same day, the Southern Alliance for Clean Energy held a press conference with four South-based climate scientists to discuss the report's regional implications.

"Southeast states with our vast coastline, rich agriculture and great forest are the most vulnerable areas in our nation," said SACE Director Stephen Smith.

The IPCC report predicts a rise in sea level of anywhere between 7 and 23 inches through the year 2100. However, those estimates are conservative, since they don't take into account recent evidence for the accelerated melting of the Greenland and Antarctic ice sheets, which could boost sea levels by an additional 4 to 8 inches, Smith said.

Such a dramatic rise would inundate coastal communities and other low-lying areas. It would also boost the surge from tropical storms, leading to an increased risk of flooding even in communities well inland from the coast. At the same time, warmer oceans would heighten the intensity of tropical storms, creating double jeopardy for people living in cyclone-prone areas such as the southeastern United States.

Besides increasing the risk of flooding, climbing temperatures are also expected to take a toll on agriculture. Some models show that higher temperatures could reduce the yields of key crops including soy, corn and sorghum by as much as 50 percent, reported Greg Carbone, a professor of geography at the University of South Carolina. Even if farmers adopt new methods, yields would probably still drop by 20 to 30 percent due to increased risk of drought and flash floods, he said.

In addition, a warming climate has important implications for the multibillion-dollar post-Katrina reconstruction effort underway on the U.S. Gulf Coast. "We need to start having serious discussions about adaptations," said Smith, who noted that policy makers are often quick to point out the cost of adapting while failing to account for the cost of not doing so.

Research meteorologist Thomas Peterson with the National Climatic Data Center in Asheville, N.C. urged planners to keep in mind what's known as the "lessening hypothesis," which holds that the thrust of development in societies is toward reducing the social costs of hazards, especially deaths, by broadening the range of adjustments. But that approach brings its own hazards. For example, building flood control structures along a river might limit the occurrence of small floods, but by encouraging increased development they ultimately increase the risk of devastation from a big flood.

Scientists have already observed a global temperature increase of .8 degrees Celsius, and another .5 degree rise is considered inevitable because of the carbon already released into the environment, Smith said. In order to avoid the worst possible effects of climate change, scientists hope to limit warming to 2 to 4 degrees Celsius.

But that's going to be difficult if the United States, the world's biggest emitter of greenhouse gas pollution, continues down the same energy policy path. In the Southeast alone, over 55 percent of the electricity produced still comes from old-fashioned, dirty coal-burning power plants -- more than any other region in the nation. In fact, if considered a country, the eight Southeastern states would rank fifth in the world, ahead of Germany, in its contribution to global warming pollution, according to a SACE fact sheet.

Despite the clear risk to our climate, however, some of the region's biggest utility companies -- Duke Energy, Florida Power & Light, TXU -- are still pressing ahead with plans to build more heavily polluting coal-fired power plants. At the same time, other utilities such as North Carolina-based Progress Energy and Georgia-based Southern Company are pushing for new nuclear plants despite the significant amount of fossil fuels burned in the manufacture and transport of nuclear fuel, never mind the long-term problem of nuclear waste storage.

"We need energy policies and practices like energy efficiency and renewable energy that solve this problem," said Smith, "not more coal-fired power plants that will only add more global warming pollution."

* * *

Meanwhile, though scientists agree global warming is real and caused by humans, that message apparently hasn't gotten through to many of the elected officials in charge of crafting our national climate policy.

Today's Think Progress blog at the Center for American Progress reports on a new National Journal poll that surveyed 113 Congress members about their position on global warming. It found that only 13 percent of congressional Republicans say they believe human activity is causing warming, compared to 95 percent of congressional Democrats:

Moreover, the number of Republicans who believe in human-induced global warming has actually dropped since April 2006, when the number was 23 percent.

How will our nation solve such a serious problem when so many of our leaders don't believe it's even real? Could this be why the United States, along with India and China, have declined to answer France's call for a new international body to address climate change?