Last year was the second warmest on record for the planet, and this year is now on par to be the planet's hottest, according to climatologists.
But in a new global broadbrush forecast, climate experts add that "the Southeast United States may be one of the most vulnerable regions to climate change."
Not only does the Southeast have the most coastline to lose in the United States - 41 percent of the lower 48 states exposed to sea level rise and intensified hurricanes - but newest projections also show:
* Heat wave events now occurring every 20 years could occur about every other year, and very hot days are projected to be about 10 degrees hotter regionwide than they are now.
* The Great Smoky Mountains National Park could lose about 17 percent of its mammalian diversity, including the red squirrel, the northern flying squirrel and the southern red-back vole.
* Half the wild trout populations are likely to disappear from the southern Appalachian Mountains because of the effects of rising stream temperatures.
These changes and more are cataloged in a 60-page draft report prepared by experts at Oak Ridge National Laboratory, the University of Georgia, the Battelle Memorial Institute and consultants for the U.S. Environmental Protection Agency.
The report defines the Southeast as Alabama, Tennessee, Georgia, North Carolina, South Carolina, Mississippi, Kentucky and Florida. In other findings:
* Tennessee could lose four to seven and a half times more pines to pests such as the pine beetle.
* The seasonal severity rating of fire hazards regionwide will increase between 10 and 30 percent.
* Regional water stresses are expected to increase as drought trends escalate in South Georgia, where pressures between Georgia, Alabama and Florida in the Apalachicola-Chattahoochee-Flint River system already are severe. Population and power use also will rise and need more irrigation, cooling and drinking water.
* The Southeast is projected to face the largest crop losses in the nation - a 10 to 30 percent decrease of nonirrigated soybean yields by about 2030, and an 80 percent loss by 2090.
"It will definitely change water availability. There's a lot of dry-land agriculture in the Southeast and that may be affected," said Dr. David C. Bader, deputy director of the Climate Change Science Institute at Oak Ridge National Laboratory.
Joel Smith of Stratus Consulting, the primary writer of the draft report, said the important question is no longer if climate change is happening, but what to do about it.
"We do have to do something about greenhouse emissions," he said. "And we have to get prepared."
As with all changes, he said, there are winners and losers.
"It's not that it's all negative. Farmers in the North are going to get longer growing seasons. People in the North's heating costs will be reduced, although they'll pay more for air conditioning.
"But as you get further south, there will be fewer and fewer of these benefits," he said. "And in the long run, there are a lot of risks (nationwide) - sea level rise, storms and a lot of other problems. And we'll have to live with the consequences. ... What do we do about living in coastal areas? How do we manage water supplies? What do we do about the forests, our agriculture, even human health? There are going to be issues with heat waves and risk of new disease. We can't wait for these things to fall on us."
This week's forecast heat wave - a string of at least seven 90-plus degree days with Saturday predicted to edge 100 - doesn't by itself indicate climate change, experts say.
"Even the Nashville flooding, and Katrina, those single events, we can't say they are because of climate change," Mr. Smith said. "We have to point to trends, and we do expect to see these kinds of things intensify over time."
In addition to national climate bills in Congress, some states have begun to make plans, Mr. Smith said.
But Tennessee, Georgia and Alabama are not among those states, according to the Pew Center on Global Climate Change. The organization tracks, among other things, what states are working on or have adopted plans or policies to address climate change. The Pew Center shows 21 states have plans completed or in the works.
But individuals can make plans, too, he said.
"Get smart on the issue. Read up," Mr. Smith said. "If you're in or near a flood plain, do you have flood insurance? If you're in wooded area where drought might cause fire dangers, do you have an evacuation plan?"
Dr. Marshall Shepherd of the University of Georgia said he and students there are working on a project to improve forecasting of regional climate change by looking more deeply at historical local weather statistics - particularly for Georgia.
"I took the last 56 years of temperature and precipitation data," Dr. Shepherd said. "It maps areas of warming and drying," and will help with future modeling projections.
Funded by the U.S. Forest Service, the researchers also are studying the implications of vulnerable populations both in urban and rural areas.
"Now we'll bore into the social groups and see who's most vulnerable to those changes," Dr. Shepherd said.
In Tennessee, Dr. Bader said the Climate Change Science Institute is working to focus Oak Ridge's climate-related research, modeling and strategies.
Dr. Bader, whose expertise is in climate modeling, said there are 23 models. They don't all agree on what will happen at regional levels, though they do all agree on what will happen globally and in North America overall.
"Weather prediction has gotten better and better over time, but climate modeling is harder to do. There's less data to work with," he said.
He said skeptics have used the modeling discrepancies and uncertainties to advocate not doing anything from a national policy standpoint, but that's a bad idea.
"We're locked into several decades of climate change no matter what we do, based on the fact that you can't change all the energy infrastructure immediately," he said.
"Big changes we make (now) as a country and world ... won't have an impact for 20 or 30 years. But if we don't make the changes now, in 20 or 30 years from now, the problem's going to be a lot worse and we'll be locked into even greater changes or we won't be able to reverse."
He said the climate change issue is much more complicated than many people understand.
"And it's not a political issue. The climate doesn't read opinion polls," he said. "And it's not like air pollution, where you can stop polluting now and in a year the problem's gone."
Continue reading by following these links to related stories: