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Farmers already adapting to erratic weather
Weather and climate aren’t the same, but near-term weather cycles and longer-term changes in climate have this in common: Both will bring more extremes of wet and dry years. So far, farmers are adapting to both.
In the short run, the odds for drought in 2013 remain high.
“There’s essentially no way the drought is going to go away,” says Don Wilhite, a University of Nebraska-Lincoln (UNL) climatologist. “It’s going to continue over some parts of the country; some areas may get better.”
Wilhite, who started the National Drought Mitigation Center at UNL, says Pacific Ocean temperatures used in longterm forecasts are neutral, with neither a La Niña (the cooler-than-normal sea surface linked to Midwest drought) nor an El Niño (the opposite of warmer waters).
Similarities between last year’s winter and this one still hint at drought, he says.
Iowa State University climatologist Elwynn Taylor shares Wilhite’s hunches.
After three years with U.S. average corn yields below the trendline, “this will probably be the fourth,” he says.
Taylor sees similarities between the widespread drought of 1988 and lingering drought in 1989. Much of Iowa escaped the second one; areas to the west did not.
“That doesn’t mean the drought won’t come back,” Taylor says. “If we have a year like 1989, which is very possible because we’ve done it four times in history, then drought is probably over to the east of Interstate 35, and it’s probably not over west of I-35.”
Taylor advises farmers west of I-35 to plant corn “at the lower end of the recommended population as opposed to the higher side.” It’s something many in the Great Plains are considering.
Taylor bases his views on historical records. “Four times we’ve had consistent yields for 18 years followed by 25 years of volatile weather,” he says. That shows up if you plot corn yields. Similar weather patterns show up in tree-ring studies going back 800 years, he says.
Layered over these weather cycles, climate is already showing long-term trends toward even more extremes.
Another ISU climatologist, Gene Takle, says farmers are already adapting to a changing climate.
“In Iowa, in the last half of the 20th century, we’ve had more years with annual precipitation of over 40 inches and less than 25 inches,” Takle says.
Until 2012, Iowa and much of the Midwest seemed to be getting wetter, not drier. That wasn’t a surprise to climate scientists. As the planet warms, the atmosphere holds more moisture. Some areas, including parts of the Midwest, were expected to be wetter in most years.
Takle is one of two convening lead authors of the agriculture chapter of the National Climate Assessment, a study mandated by a 1990 federal law. A draft of the assessment, written by 240 scientists, came out last year. It describes how increasing climate change will affect different regions of the U.S. and different sectors of the economy.
At a regional forum in Lincoln, Nebraska, to get public reaction to the assessment, Takle said agriculture is one sector of the economy that’s ahead of many in adapting to climate change.
“Farmers have always been adapting,” he said. “They adapt to everything. They’ve been very good at it.”
He gave farmers credit for changes that will surprise no one in agriculture: planting earlier and harvesting later in longer growing seasons; using larger machinery to plant faster in wet springs; increasing plant population in most years to take advantage of more moisture; and putting tile even on sloped surfaces to drain the excess.
Partly because the Corn Belt is an area not expected to completely dry out soon and because farmers are adaptive, Takle’s view of climate change and agriculture is almost optimistic – for a while.
“Overall, total production will not decline in the first half of the 21st century, but it will decline after that unless we develop some new innovations,” Takle said.
By 2050, climate models show temperatures rising between 1.8°F. and 5.4°F.
First, that will affect crops in California’s already hot central valley, where yields of irrigated corn, tomatoes, rice, wheat, cotton, and sunflowers will decline. Only alfalfa will continue to yield as much, with adequate water.
The Corn Belt won’t escape. The number of nights with high temperatures that hurt corn production may increase up to 30%.
One of the greenhouse gases driving climate change, carbon dioxide, has its own detrimental effects. It reduces protein content in soybeans and alfalfa. It encourages the growth of some weeds more than crops. Glyphosate loses efficacy on weeds grown in the higher CO2 levels.
Back in his Iowa State University office, Takle shares the complexity of climate science.
Big mainframe computers simulate weather patterns with huge amounts of data. “It will take us a week to run a year’s worth of simulations,” he says. The models usually run for months to generate 30 to 50 years of projections. Over the past 40 years, the models have been fairly accurate.
Models aren’t precise enough to agree on how a region, like the Midwest, will change, Takle says. “We still have the view that the northern tier of states is going to have increased precipitation. The Southwest will dry out.”
Climate science may not be exact, but that’s no comfort to those who study it.
“The biggest concern I have is that the Earth system is changing so much that the past may not be a good indicator of the future,” says Ghassem R. Asrar, director of the World Climate Research Program in Geneva, Switzerland. “We may be seeing a transition to a system that is becoming nonstationary.”
Asrar expects warmer and drier conditions in the Great Plains.
“What we know today of the type of climate we have in the U.S. Midwest, Northeast, and Northwest vs. the future climate projections – which show significant warming trends and shifts of sufficient magnitude – causes us to really question our ability to grow certain crops that we grow in these regions today,” he says.
Editor's Note: Writer John Dietz contributed to this story.