Neb. experiences stark and toxic hangover from this year’s record drought

Source: Nayantara Narayanan, E&E reporter • Posted: Thursday, October 18, 2012

Is Nebraska in the grip of a long-term drought? Not yet, says Mark Svoboda, climatologist with the National Drought Mitigation Center, but with an ominous caveat. “We are seeing impacts that we normally don’t see until a multiyear drought.

In the hot and dry weather of the past six months, Nebraska has seen its water table levels — both surface and subsurface — plunge, high mortality among its trees, and drought-specific plant and animal disease.

“Last winter, or the lack of winter, if you will — that was strike one. The warm spring with the lack of moisture was strike two,” Svoboda said. He will not call a drought long-term until he sees drought conditions persist for at least a year. But the dismal evidence he needs is rapidly accumulating.

Almost all young trees across Nebraska are dead or dying. “There have been many trees planted as windbreakers and in conservation plans. Unless they were irrigated, mortality has been 90 to 100 percent,” said Dennis Adams, the rural forestry program leader for the Nebraska Forest Service.

“I have a tree farm myself, and I have almost 100 percent mortality,” added Adams, one of many farmers facing the worst drought in his memory and the worst single-year drought since the 1930s.

What is unusual and worrying is that older trees are dying, too — firs, spruce and even some hardwood deciduous trees. Only pine seems to be holding out, according to Adams.

A toxic corn crop

Trouble is mounting for corn growers, too. Already faced with below-average produce, they are now finding aflatoxin in the crop. Aflatoxin is a chemical produced by a mold that grows on corn, especially in a dry growing season.

“The infestation is patchy,” said Graham Christensen, public affairs director of the Nebraska Farmers Union. “We’ve seen it in central and eastern parts of the state.”

Aflatoxins in large amounts are carcinogenic, and the Food and Drug Administration has set the limit for aflatoxin in food for human consumption at 20 parts per billion. The FDA limit ensures that food companies like Cargill that buy grain from Nebraska’s farmers don’t buy corn with aflatoxin above that level. “This guy had a crop that was 300 ppb,” Christensen said of a fellow farmer. “What does he do? Just hope he has insurance.”

Animal feed can contain up to 300 ppb, and Nebraska is one of six states that have received FDA approval to blend corn containing more than 20 ppb aflatoxin with clean grain as animal feed.

But ethanol makers that use corn residue as livestock feed won’t accept contaminated corn. The process of distillation raises the concentration of aflatoxin above permissible limits, rendering the results unusable.

The drought is pushing up the death toll among deer in the state. Every fall, Nebraska sees some deer deaths due to epizootic hemorrhagic disease (EHD), which is caused by a virus and transmitted through the bites of midges. This year, less water and less forage have forced the animals to congregate in larger numbers in smaller areas, allowing the disease to spread faster.

“We have had a significant loss of deer this year partly caused by the drought,” said Pat Molini, wildlife district manager at the Nebraska Game and Parks Commission. “We have at least 6,000 reports of dead deer. Some may not be because of drought, some may be exaggerated. But it is a significant outbreak.”

The death toll among deer in an average year is less than 5 percent of the deer population. Molini hopes the loss will be less than 15 percent this year.

Is this the new normal?

The fear in the Midwest is that drought conditions are here to stay. The Nebraska Farmers Union’s Christensen worries that the aflatoxin spread marks the beginning of many infestations as temperatures rise and new pests migrate north to Nebraska. “Probably the greatest fear we could have, the seriousness of this kind of drought, if we had a year or a couple of years more like this, it could take a more extreme toll,” he said.

His fears appear to be well-founded. Droughts could be the new normal, according to a study by collaborators at the University of Tennessee, Los Alamos National Laboratory, the U.S. Geological Survey, the University of Arizona and Columbia University.

The study finds evidence from tree rings that the latest drought that began in the late 1990s and lasted through the following decade could become the worst in 1,000 years.

University of Tennessee scientist Henri Grissino-Mayer has examined tree rings from A.D. 1000 to 2007 and found that the United States has suffered many “mega-droughts.” A climate-forest stress model suggests that 2050 will see worse drought and tree mortality than any it has experienced in the past 1,000 years.

Even the outlook for the next few months is bleak. Svoboda said, “Once we get into winter, we will be close to calling it along a long-term drought.”

He sees no relief from drought unless there is heavy snowfall in the Rockies over the winter and heavy rainfall in the plains. There is right now a shortfall in precipitation of 9 to 12 inches. And where there are no clouds, there is no silver lining. “Overall, this drought was so far-reaching and so intense, it’s not going to magically go away,” Svoboda said.