Climate change report projects Georgia impacts

Atlanta, Miami, New Orleans, and Tampa have already had increases in the number of days with temperatures exceeding 95°F, during which the number of deaths is above average.

Water availability

Water resources in the Southeast are abundant and support heavily populated urban areas, rural communities, unique ecosystems, and economies based on agriculture, energy and tourism. The region also experiences extensive droughts, such as the 2007 drought in Atlanta, Georgia, that created water conflicts among three states.

The Appalachicola-Chattahoochee-Flint (ACF) River basin in Georgia, Alabama, and Florida supports a wide range of water uses and the regional economy, creating challenging water-sharing tradeoffs for the basin stakeholders. Climate change presents new stresses and uncertainties.

Because of Clayton County, Georgia’s, innovative water recycling project during the 2008-2008 drought, they were able to maintain reservoirs at near capacity and an abundant supply of water while neighboring Lake Lanier, the water supply for Atlanta, was at record lows.

Groundwater withdrawals are intense in parts of the Southwest and Northwest, the Great Plains, Mississippi Valley, Florida and South Georgia, and near the Great Lakes.

Agriculture

The 2007 drought cost the Georgia agriculture industry $339 million in crop losses … In Georgia, climate projections indicate corn yields could decline by 15% and wheat yields by 20% through 2020. In addition, many fruit crops from long-lived trees and bushes require chilling periods and may need to be replaced in a warming climate.

The national report on climate change that ripped through the headlines this week offers Georgians some solace, ample cause for anxiety and, of course, endless fodder for debate.

It foresees widespread coastal flooding across the Southeast due to rising sea levels, but says Georgia’s coast is less vulnerable than some. It says temperatures will rise, causing more extreme heat events that affect public health, agriculture, energy and forestry. And it predicts that competition will intensify for surface water in watersheds such as the Chattahoochee River basin.

The report, commissioned by Congress, is the third of its type. It represents the combined work of hundreds of scientists, including some in Georgia.

Its release was greeted by high praise and sharp denunciations from predictable quarters — much of it from speakers who admitted they had yet to read the report’s 800-plus pages.

Jenna Garland, a spokeswoman for the Sierra Club in Atlanta, applauded the document as a call to action produced by top scientists. “In Georgia, families are already paying the cost of extreme weather and health risks fueled by climate destruction,” she said.

But Dewey Lee, an agronomist at the University of Georgia who also serves as executive director of the state’s corn growers’ association, said its members are likely to place more stock in the wisdom borne of experience.

“I think it’ll take a while for people to separate the politics of this out,” Lee said, noting that it’s a government report. “If you were to … talk to farmers who’ve been through 50 seasons, 60 seasons, they’d tell you, ‘Ma’am, every season’s different,’” Lee said. “’Climate change? It always happens. We always struggle with drought. With heavy rainfalls. With cold. With freeze.’”

Even within the Georgia Tech faculty, responses were mixed.

Judith Curry, chairwoman of Tech’s school of earth and atmospheric sciences, does believe climate change is happening and that people’s actions are contributing to it. But she said the report stripped the issue of its nuance.

“The phrase ‘climate change’ is now officially meaningless,” Curry wrote in her blog. “The report effectively implies that there is no climate change other than what is caused by humans.”

Michael Chang, the deputy director of Tech’s Brook Byers Institute for Sustainable Systems, said that from what he’s heard, “I’d have to say it sounded consistent with other reports that have been done in the past.” While climate may vary naturally, he said, “the question is: Are we also beginning to see more extreme events,” such as storms, cold snaps and heat waves?

Rather than dismiss the report because some of those questions remain unanswered, he said, Georgia scientists and policy makers would be wise to concentrate on filling the knowledge gaps. “If they’re important, are we prepared to address them or adapt to them in a responsible way?”

Gerrit Hoogenboom, a professor of agrometeorology at Washington State University who has projected the impact of rising temperatures on Georgia farmers, didn’t question the scientific rigor of the report. And he has no question that farmers need to be preparing for extreme weather events, or that people need to generate less pollution. But he had “mixed feelings” about the report overall, he said.

For one thing, like much scientific prognosticating these days, it relies on computer models to predict what will happen in the decades ahead. And he is uneasy with people relying on those models too much, because he knows their strengths and weaknesses all too well: His own work is based on them.

In fact, Hoogenboom’s work is the basis for one of the report’s more dramatic assertions about Georgia: that by 2020, corn yields could decline by 15 percent and wheat yields by 20 percent.

Those numbers, however, were published more than a decade ago, looking ahead 20 years, he said. Newer data shows they “may be too drastic,” Hoogenboom said. He still believes 2020 yields will show a decline, but a smaller one.

Matthias Ruth, a professor at Northeastern University who studies ecological economics, said such concerns miss the point. Ruth contributed to other parts of the report, and in the past has done independent research on the impact of climate change on Georgia.

Certainly computers’ predictions are imperfect, he said. But they are the best tool available, and the general conclusions of this and previous reports have been borne out by experience, he said.

“Even if we quibble over the odd number here or there, the trends are there, and they’re actually accelerating faster than we anticipated,” Ruth said. “The longer we wait to make these adjustments, the more climate change we have committed ourselves to, and the more serious the repercussions will be.”