Climate models see hotter future for Southeast
Sep 5, 2001 12:00 PM, Paul Hollis
Hot enough for you? If you think so, then you'd better brace yourself, because it's going to get much hotter. Recently released scientific climate models are predicting a sizzling future for the Southeast, with some changes occurring gradually over the next century and others expected to occur within the next 30 years or so.
All of this leaves some farmers asking, “How much worse can it get? “Although rainfall over the Southeast has improved over last year, some areas are experiencing their fourth consecutive year of drought. But, according to the experts, it can and will become hotter and possibly drier in the future.
In a report by the National Science and Technology Council, hundreds of scientists in fields from agriculture to zoology predicted the impact of global warming in the United States. Looking at Georgia in particular, here are some of their findings:
Sea levels could rise two feet or more along the coast, threatening barrier islands and endangering miles of beaches and ecologically crucial coastal marshes.
Agriculture and forestry may benefit from warmer conditions and longer growing seasons, but only if rainfall increases. If rainfall declines, agricultural production in the Southeast could plummet 60 percent by 2030, devastating rural Georgia.
With higher temperatures and faster rates of evaporation, the state's already strained water resources could be overwhelmed. One of the two computer models cited by U.S. scientists predicts a 19 percent decline in rainfall by 2030, which would dry up some of the region's rivers.
“If that scenario proves true, it will be extremely worrisome for the Southeast,” says Patrick Mulholland, senior scientist at the Oak Ridge National Laboratory in Tennessee. “With higher temperatures, plants and people both will require a lot more water, and without a fairly substantial increase in precipitation, water availability will become a real problem.”
While some climate models predict a warmer and wetter climate for Georgia, with an average warming of about five degrees F., others predict more dramatic changes. One Canadian model sees average annual temperatures rising by nine degrees. And, because the Atlantic storm track moves eastward — out over the ocean — rainfall would drop significantly. As soon as 2030, annual rainfall in the Southeast declines by 20 percent under the Canadian scenario.
So which forecast is more accurate? “If they give different answers, as they have for the Southeast, then we have to look at the models as giving us a range of possibilities,” says Robert Dickenson, professor of atmosphere dynamics and climate at Georgia Tech.
The most recent pattern of irregular rainfall seen in Georgia and other Southeastern states could be an early harbinger of a rapidly changing climate, says Aris Georgakakos, director of the Georgia Water Resources Institute at Georgia Tech.
“The computer models project the climate going through cycles that are more intense, with more variability in rainfall,” says Georgakakos. “And if you look at the record, you see just that kind of pattern happening around Georgia.”
Ironically, the rainfall worries of farmers might be eased with help from an unlikely source. It's predicted that levels of carbon dioxide in the atmosphere will double by 2100. If this occurs, research also suggests that it also could double the rate of photosynthesis in some plants. Additional carbon dioxide also reduces the amount of water that a plant requires. This phenomenon could partially offset less rainfall.
Thanks in part to more carbon dioxide, per-acre yields of non-irrigated peanuts could rise 14 to 17 percent in Georgia by the end of the century, predicts University of Florida researchers. Peanut yields on irrigated land would rise by 2 percent to 7 percent.
Overall, agricultural productivity in the Southeast would increase by more than 10 percent by 2030 and by more than 20 percent by 2100, according to computer crop models.
e-mail: phollis58@mindspring.com
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