Tennessee climate change is so subtle it's hard to gauge

The U.S. Department of Agriculture chief calls climate change "one of the greatest threats facing our planet," but little attention is being paid to it in Tennessee's farming world.

More rain is falling in autumn in the Southeast than a century ago. Droughts have increased in spring and summer, and the temperature has made a slight move upward, particularly since 1970.

It's projected to continue to rise, according to the U.S. Global Change Research Program. Increasingly extreme weather is likely, such as heavier downpours and more intense droughts in some areas.

Yet change in Tennessee could be difficult to tabulate, according to Joanne Logan, an associate professor of biosystems engineering and soil engineering at the University of Tennessee.

"In Tennessee, everything is pretty subtle," she said, adding that research has not been plentiful when it comes to agriculture and climate change here.

If small changes are occurring under the radar, a trigger point could be reached suddenly where ecosystems as a whole could fail, unable to make changes quickly enough to keep up, she said.

Logan has set up a climate change clearinghouse website for the UT Institute of Agriculture, starting with climate data and available reports. More information is needed to determine what incremental changes may be taking place between pathogens and plants, she said.

The ecology of bees and bats could get out of kilter, for instance, upsetting a balance of nature that has taken thousands of years to be established. Both bats and bees have been hit with mysterious ailments that have been wiping out whole colonies.

In Tennessee, climate data show that more rain is falling in a shorter period of time and falls are wetter. Night temperatures have been warming in the last 30 years, particularly in urban areas where pavement and roofs have taken the place of grass and forests. More humidity in the air could hold radiation around the earth, even when the sun is down. That could slow plant growth, Logan said.

"These are all just really subtle things that are happening," she said of the temperatures. "We're not seeing any huge thing — no canary in the cave in Tennessee that we know of."

It's difficult for Tennesseans to be alarmed when faraway tundra melts or oceans rise, she said. But there are things worth noting here.

"Who would have thought fire ants would make it up this far north?" she said.


Droughts more frequent

In the Southeast as a whole, the average autumn rainfall has jumped by 30 percent from 1901 to 2008, and heavy rains have increased 27 percent in the fall, data from the multi-agency U.S. Global Change Research Program show.

Droughts are more frequent, too.

While the Tennessee Department of Agriculture doesn't address the issue, the Tennessee Wildlife Resources Agency has put out a climate change report and the Tennessee Department of Health has issued a statement.

The TWRA report projects a mean temperature increase of 5 degrees over most of the state in the next 50 years. Rainfall changes would vary over the state's regions.

Brook trout, the state's only native trout, might not be able to survive, and migratory songbirds could alter their ranges. Larger floods could increase erosion and invasive species could spread. Wood duck wouldn't be found as often raising their young along waterways and in wetlands. Drying of prairie potholes and marshes to the north could mean fewer mallard, northern pin-tail, blue-winged teal and other ducks migrating to Tennessee in winter, resulting in shorter hunting seasons.

The state Health Department says higher temperatures will lead to heat-related illnesses, and organisms that transmit viruses and other pathogens will be able to infect people in larger ranges.

U.S. Agriculture Secretary Tom Vilsack stepped up last month at the United Nations Climate Change Conference in Cancun, Mexico, to say farmers and others can help and benefit, too.

Landowners can reduce greenhouse gas emissions, sequester carbon in the land and improve their financial bottom line, he said, by providing carbon mitigation services in emerging greenhouse gas markets.

The gas can trap heat around the planet, stimulating weather swings and climate change. More of the gases have been spewed into the atmosphere from humans with the advent of factories, industries and vehicles.

Farmers' views differ

Two longtime Nashville-area farmers, Bob Strasser of Nashville and A.B. "Johnny" Hicklen of Nolensville, who keep close daily watch on the weather, have differing views on the issue.

In recent years, they've seen a late freeze decimate fruit and other trees in the spring, followed by serious drought that left many farmers without feed for cattle.

Record-breaking temperatures have been tallied, and unprecedented rains in May flooded several communities, including Nashville.

Strasser, 52, a third-generation dairy farmer in Nashville's Pennington Bend, doesn't see a climate shift but rather the usual weather fluctuations that occur.

He does detect one human-caused problem.

"I don't know that drought is going to be any worse than the past, but water conservation and usage are going to be a big issue," he said via cell phone as he put out food for his cows.

"We strain our resources with concentrated growth."

Atlanta, with its burgeoning population, has needed more water supplies than it has, intensifying ongoing wars over water among Georgia, Alabama and Florida.

That's a population matter, not climate, Strasser said.

Hicklen said he gave up 30 years of strawberry growing after planting an early spring crop became too unpredictable with a changing climate.

He moved to growing pumpkins and gourds in the fall and winter, producing more than 11,000 pumpkins last year.

"Something has drastically interfered with our normal pattern of rain," Hicklen, 79, said as he sat in his Williamson County home for a cup of coffee.

"I know seasons will change, but like with our strawberries, it was an almost 100 percent turnaround."

Hicklen said he took notice in the 1980s when weather forecaster Boyce Hawkins, now deceased, talked about a changing climate. He had said the ash and gases from the violent Mount St. Helens volcano (right) eruptions in the Pacific Northwest would take 50 years to clear.

"It hasn't been the same since," Hicklen said. "The way our summer is dry as a bone. And when we do get a rain, thunderclouds are so rambunctious they blow everything away.

"The storms have so much wind."

He blamed not just volcanic eruptions but also coal-fired power plants "and the emissions from these millions and millions of automobiles. "Where is that stuff going?" he said.

Source:
The Tennessean, "Tennessee climate change is so subtle it's hard to gauge", by Anne Paine, accessed January 3, 2011