Global climate change poses severe public health challenges for the world, and some of the biggest challenges will come here in the southeastern United States, researchers at the federal Centers for Disease Control and Prevention believe.

A hotter world isn't the only health threat people face as the globe grows warmer, but it's one of the biggest.

"Heat causes more deaths than all other weather causes combined," said George Luber, associate director for climate change in the CDC's Division of Environmental Hazards and Health Effects.

Scientists expect more extreme weather events because of human-induced global warming, including more heavy rainfall events, more severe storms, more and stronger droughts, and heat waves like the one that withered Europe in 2003, he said.

Official estimates pegged the death toll from the 2003 heat wave at about 30,000, including nearly 15,000 in France. But the real count was likely more than twice that, Luber said in a talk sponsored by UGA's Georgia Initiative for Climate & Society.

"This is obviously going to be a challenge for some countries to deal with," he said.

The Southeast warmed up less than other parts of the United States as atmospheric carbon dioxide concentrations increased in the atmosphere, Luber told an audience on the UGA campus last week. Some scientists believe that's at least partly because forests were re-established in the South, heavily logged and cut over for cotton fields in the 19th and early 20th century.

But computer models now predict the already-hot Southeast will experience a greater increase in the average heat index than any other part of the country, Luber said.

Demographic trends will amplify the heat toll, he said. For the first time in human history, more humans live in cities than in rural settings, and cities intensify heat. And populations are growing older and more vulnerable across the world, he said.

But heat is only one of the public health threats of global climate change, said Luber, a UGA Ph.D. graduate in medical anthropology.

As urban temperatures go up, so will ozone, which is harmful to human lungs.

Elevated levels of carbon dioxide are stimulating plants like ragweed, which are not only producing more allergy-aggravating pollen, but bigger and more allergenic pollen particles, he said.

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