CHICAGO (Reuters) - It can't happen here, can it?
The United States, the breadbasket and supplier of last resort for a hungry world, has been such an amazing food producer in the last half-century that most Americans take for granted annual bounteous harvests of grain, meat, dairy, fruits, vegetables and other crops.
When horrific images of drought or famine in Africa, Asia or other regions land in American media, America is usually first in line with food aid shipments, air drops, and other rescue efforts from its seemingly endless stores.
The U.S. alone accounts for half of all world corn exports, 40 percent of soybean exports and 30 percent of wheat exports.
But climate change fears are sounding some warning bells.
Some scientists and agronomists are becoming increasingly concerned about the real effects they see now on growing conditions in the Midwest, the vast black-soiled region long the core region of the U.S. agricultural miracle.
They also say that not only skeptical farmers but also government authorities are trying to quietly adapt, from equipment to planting to research.
"We don't have a long-term reserve. We have a global food supply of about 2 or 3 weeks," said Eugene Takle, Professor of Agricultural Meteorology and Director of the Climate Science Program at Iowa State University.
"We've become insensitive to climate -- with air conditioning, irrigation and better practices," he said. "Well, I think we need to rethink that. Just how vulnerable are we?"
Takle and others say the future is now.
"It's not the long-term climate trends," Takle says, "It's the variability. It's the extreme events that have brought the vulnerability of agriculture to climate into the forefront. We think about, and wring our hands for awhile."
Jerry Hatfield, Laboratory Director at the National Soil Tilth Laboratory in Ames, Iowa, has worked with other scientists in research for the United Nations Intergovernmental Panel on Climate Change. He says climate change is occurring right now, as is adaptation to it, in the U.S. farm belt.
"We don't have to think about 2030 or 2050, in the recent memories we've had a lot more variability in our weather," Hatfield said. "This increasing variability of weather, which is associated with our changing climate scenarios, is going to continue to increase the variability in production.
"That's what concerns a lot of us," Hatfield said.
The IPCC, which has been attacked by climate change skeptics, concluded in 2007 that increased frequency of heat stress, droughts and floods are "creating the possibility for surprises, with impacts that are larger, and occurring earlier, than predicted using changes in mean variables alone."
"Climate variability and change also modify the risks of fires, pest and pathogen outbreak, negatively affecting food, fiber and forestry," the Panel said.
Despite the attacks by skeptics, IPCC's conclusions have been accepted as valid by institutions like the U.S. National Academies of Sciences.
In June 2009, the science academies of the G8 countries, plus Brazil, China, India, Mexico, and South Africa, demanded action to address global climate change that "is happening even faster than previously estimated."
Takle said Midwest farmers are already adapting.
"Farmers say they don't believe in climate change, but you look at how they spend money and are adapting," he said.
Takle pointed to bigger machinery to allow faster and denser seeding amid rainier springs in the Midwest. Frosts are trending later so crops are kept in fields longer to dry.
But many of the changes are more subtle and hidden than the weather events that grab the headlines, like the massive wildfires, flooding and tornadoes that have hit agricultural areas of the Midwest, Plains and Southwest this year.
Takle said measurable trends of more humidity, for example, has led to higher night-time summer temperatures in the Corn Belt and likely trimmed corn yields in recent years. Corn likes hot days but cool nights.
In Iowa, dew point temperatures have risen 3-1/2 degrees Fahrenheit in the last 35-40 years, equating to 13 percent more moisture in the air during the summertime, he said.
"It's very important that we recognize the vulnerability," Takle said. "We have situations like in Texas. Huge reservoirs have just vanished. You can't do a work around."
The U.S. Agriculture Department this year issued its first grants to study crops and climate change.
"If you're interested in adapting to changes in climatic norms you need to have access to diversity," said Randy Wisser of the University of Delaware, who will study the genetics in exotic tropical maize to see how this might help farmers.
Other grants will address greenhouse gas emissions that affect climate, notably methane from livestock and carbon dioxide from growing crops.
"We are just trying to find a suitable way to keep these farmers in business. It took generations to create the problem it will take generations to fix the problem," said William Horwath of the University in California, who will develop strategy for rice growing in the Sacramento-San Joaquin Delta.
"It's a pretty darn complex problem," Hatfield said. "We poke at it, but we need to get very serious about how do we think about adapting our crop production goals to the concepts of variability."
Reporting by Christine Stebbins; Editing by Peter Bohan