Wetter springs, hotter summers: Climate change threatens Iowa farm economy
What you need to know: The recently released Fourth National Climate Assessment contains these warnings for the Midwest and Iowa:
- Crop yields could be reduced due to ongoing changes in seasonal rainfall and the severity of heat waves
- A potential 25% drop in corn yields by the middle of the century
- Urban areas could see more damaging floods, especially in the spring
- Cleaning up Iowa's waterways will become even more challenging as a shifting climate makes solutions more difficult
- Changes in technology will likely not allow adequate adaptation
A new climate change report carries grave warnings for Iowa farmers.
Intense heat waves could prevent corn and soybeans from pollinating, leading to greater risk of crop failure.
Heavy spring rains — likely followed by summer droughts — will tighten an already shortened planting window, exacerbating soil erosion and nutrient runoff that threatens Iowa's drinking water.
Productivity could drop to 1980s levels without a significant increase in the amount of seed, fertilizers and pesticides needed to raise a crop.
The grim forecast is part of the Fourth National Climate Assessment, a federal study mandated by Congress and completed every four years.
"Any change in the climate poses a major challenge to agriculture through increased rates of crop failure, reduced livestock productivity and altered rates of pressure from pests, weeds and diseases," the report says.
It could mean up to a 25 percent drop in corn yields by mid-century, a potential hit for Iowa, the nation's largest corn-producing state.
Climate change will cost farming and other U.S. industries "hundreds of billions of dollars" annually by the end of the century, according to the report released this month and written by more than 300 federal and non-federal experts.
The pressure on farms brings additional stress for rural communities, whose financial fortunes are closely tied to agriculture, the report says.
Climate change has also brought Iowa benefits for farmers, including increased moisture that held down maximum summer temperatures, warmer winters, and nine more frost-free days since 1901.
Climate change is likely one reason farmers have seen "record yields over the past four or five years ... not that we haven't had issues," said David Miller, the Iowa Farm Bureau Federation's director of research.
But "at some point, the negatives will outweigh the positives," Miller said. "The question is how quickly can agriculture adapt."
A shift that unmasks warming
Last summer provides a snapshot of climate change's impact in Iowa: The Des Moines metro area experienced massive flooding in late June, filling thousands of basements with water and sewage and causing millions of dollars in damage.
About 80 families were homeless and one man died in the storm.
Farmers struggled with intense spring rains that forced many growers to shift from corn to soybean production. And one of the wettest falls in state history slowed the harvest and raised concerns about mold and toxins that can make corn dangerous for livestock.
"Over the past 30 years, increased rainfall from April to June has been the most impactful climate trend for agriculture in the Midwest," the report says.
In Iowa, annual average temperatures have increased "more in the winter than in the summer, and more at night than during the day," said Gene Takle, a retired Iowa State University climate scientist.
"The enigma we have is that, while in the growing season, the night time temperatures are going up, while the daytime maximum temperatures are going down," said Takle, who was an author of the Midwest climate assessment. "It's counter-intuitive."
"The excess rain that we're getting in the spring and summer is playing a role in the decline in extreme temperatures," he said.
More energy is used to evaporate water than to heat the air, holding down maximum temperatures. But that's likely to change.
Heat waves in the Midwest are likely to get hotter — the largest increase nationally —combined with a decline in late summer rainfall, Takle said.
That shift "unmasks the warming that's been going on," he said.
A five-day heat wave in central Iowa now averages 90 to 95 degrees in five out of every 10 years, Takle said.
By 2050, the average heat wave will climb 7 degrees. And once every 10 years, it will spike 13 degrees, pushing the five-day heat wave as high as 108 degrees.
"Increases in growing-season temperature in the Midwest are projected to be the largest contributing factor to declines in the productivity of U.S. agriculture," the report said.
Extreme weather is on most farmers' minds
Farmers already are adapting to climate change, while other industries are at the starting gate, says Josette Lewis, an Environmental Defense Fund associate vice president.
"Adaptation hasn't been as strong a message for other economic sectors. It's been more about mitigation," Lewis said. "And we're starting to see that we need both, across the board. That's what agriculture has been doing for a number of years."
Ray Gaesser, who raises corn and soybeans on 5,000 acres near Corning, says most farmers are already "managing for extreme weather events."
Over the past decade, he's seen more intense rain events — 4-inch downpours over an hour or 8 to 10 inches in a day.
"It's top of most guys' minds," said Gaesser, who farms with his son, Chris. "We live with Mother Nature every day and we're trying to adapt."
Like many Iowa farmers, Gaesser has been fighting soil and nutrient erosion for years: adding terraces on hills to slow and hold water.
He's decided against tillage — called "no till" — which leaves the soil undisturbed and corn stalks and soybean stubble on the field to reduce soil erosion and build organic matter that increases yields and better absorbs rain.
And he's growing cereal rye cover crops over the winter, which holds soil and nutrients such as nitrogen in place, especially during gully-washing spring rains.
Gaesser and his son also invested in more planting, harvesting and drying equipment to better cope with less time to put in and take out their crops.
"We're geared up to plant and harvest earlier and more quickly. And I'm glad we did," Gaesser said.
Climate change makes Iowa's clean water goals tougher to reach
The report holds concerning news for Iowa about water quality: The threat of harmful algal blooms increases with climate change, thanks to warmer temperatures and heavy precipitation.
Iowa already struggles with harmful algal blooms, which can introduce cyanobacteria into lakes, rivers and streams used for recreation or drinking water, making it dangerous for people and pets to use.
Iowa is already under pressure to cut the nitrogen and phosphorus leaving the state and contributing to the Gulf of Mexico dead zone, an area of low oxygen that's unable to support aquatic life during the summer.
Iowa leaders this year agreed to spend $282 million on water quality over 12 years, with about $156 million available to add cover crops, bioreactors, wetlands, saturated buffers and other practices experts say will keep excess nutrients from polluting Iowa’s lakes and streams.
But the money will trickle in slowly over the first few years and fall short of the $1 billion experts estimate is needed annually to meet the state's clean water goals.
Climate change "makes the mountain Iowa has to climb on water quality a little steeper," Lewis said, adding that urban-rural water quality partnerships will grow even more important.
"Changing climate can exacerbate (challenging) relationships between agriculture and the increasingly urban populations in farm states," Lewis said, pointing to California's fight over water during a five-year drought that ended last year.
"Increasingly, rural landscapes must be part of the solution," she said.
Can technology overcome hit to yield?
Miller, Farm Bureau's research director, says he expects technological gains will help farmers address climate change.
For example, Iowa and Indiana researchers are testing how farmers can capture water and nutrients that run off fields and store it for later irrigation, said Chris Hay, a senior environmental scientist at the Iowa Soybean Association.
And improved seed genetics that enable plants to better withstand drought, disease and other growing challenges are helping drive U.S. yields.
Those efforts are expected to improve with CRISPR, gene-editing technology that enables scientists to more quickly and precisely change seed traits.
But the report warns that technology is unlikely to overcome climate change's challenges.
"Trends toward warmer, wetter and more humid conditions provide challenges for field work, increase disease and pest pressure and reduce yields to an extent that these challenges can be only partially overcome by technology," it said.
The biggest challenge raised in the report for agriculture is "whether we can maintain productivity gains over the next 20, 30 years," Miller said.
Climate change's economic impact
Climate change's economic impact gets sharper focus in the latest national assessment, says Jerry Schnoor, a University of Iowa professor in civil and environmental engineering.
The cost is high, from medical expenses and lost work time to increased utility bills and storm damage to roads and other infrastructure. Some examples:
LOST WORK HOURS: Extreme heat in the Midwest is projected to result in losses in labor and associated losses in economic revenue up to $9.8 billion per year in 2050, rising to $33 billion per year in 2090.
DAMAGE TO ROADS: The Midwest is among the regions with the largest expected damages to infrastructure, including the highest estimated damages to roads, rising from $3.3 billion per year in 2050 to $6 billion per year in 2090. Climate change is projected to increase the costs to maintain, repair and replace infrastructure.
FLOODS: Winter and spring precipitation is important to flood risk in the Midwest and is projected to increase by up to 30 percent by the end of this century. The average annual damages from heightened flooding risk are projected to be in excess of $500 million by 2050.
Flooding already has taken a heavy toll on Iowa, costing residents, businesses and farmers about $18 billion over nearly three decades, a University of Iowa study shows. The state ranks fourth nationally in the number of floods since 1988.