Yield Decline Projected for 6 Major Crops – National Climate Assessment – DTN

Soybeans. ©Debra L Ferguson Stock Photography

Farmers in some regions of the country could see higher short-term productivity because of a warming climate, but crops and livestock face greater risks if more steps aren’t taken to curb the rise in greenhouse gas emissions, the National Climate Assessment warns. 

Farm groups and experts say farmers could be caught between policy changes that raise their production costs and climate impacts that erode their productivity over time.

Yields for crops such as corn, soybeans, wheat, rice, sorghum and cotton are projected to decline as the century continues because of higher temperatures, changes in water availability, disease and pest outbreaks, the report cites.

The National Climate Assessment (NCA) is a congressionally mandated report that is drawn from the work of 13 federal departments and agencies, including the U.S. Department of Agriculture, which took a lead on the specific agriculture chapter in the report.

Katherine Hayhoe, a climate scientist at Texas Tech University and a primary author on the report, said this report shows how climate is already changing, affecting different regions and sectors, and how the U.S. is responding to a changing climate. Hayhoe summarized the 1,600-page report as such:

“Climate change isn’t a distant issue any more. It’s affecting every single one of us, in every part of the U.S. across almost every sector. And the more climate changes, the more serious and even dangerous the impacts will become.”

The climate assessment has one major skeptic, President Donald Trump, who reiterated Monday when asked about the economic impacts, “I don’t believe it.”

The assessment highlights long-term economic impacts to different sectors of society under higher emissions and lower emissions. Combined, overall economic damages of higher pollution levels could average more than $500 billion annually every year. Hayhoe noted that compares to the costs of meeting the Paris climate accord that put U.S. costs between $1 trillion and $1.4 trillion over 40 years.

Agriculture is just a small slice of annual economic losses compared to other challenges such as labor losses, extreme temperature mortality and coastal property damage. Looking at the agricultural chapter of the NCA, several elements in the report show linkage to programs in the farm bill, including conservation, nutrition, research, renewable energy, rural development and trade.

In the midterm — the next 25 years or so — not every region or crop is affected the same way. There are winners and losers depending on growing seasons, higher carbon dioxide, fertilization and higher moisture levels in some regions. Over time, though, scenarios with higher pollution levels worsen the outlook for agriculture, said Bill Hohenstein, director of USDA’s Climate Change Program.

“Longer term, the implications are decidedly more negative across a broader array of crops and regions,” Hohenstein said.

Many of the impacts to agriculture go beyond production changes tied into the price of food globally and changes in trade flows. Food security is already a global problem and “is likely to become an even greater challenge as climate change impacts agriculture,” the report states.

MIDWEST YIELD LOSSES

The Midwest is projected to see higher growing-season temperatures and more humidity in the spring through midcentury. The region, including Illinois, Indiana, Iowa, Michigan, Minnesota, Missouri, Ohio and Wisconsin, is expected to see increased rainfall, increasing the likelihood of soil erosion in the area as well.

Yield declines for corn by midcentury could range from 5% to 25% broadly over the region. Meanwhile, soybean yields could fall 25% across the southern part of the Midwest while increasing in the northern part of the region. Heat stresses will start to plague the corn crop and continue to reduce yields as the decades continue.

DTN Senior Ag Meteorologist Bryce Anderson pointed to elements in the climate assessment highlighting areas of heavy precipitation, explaining that those events affected the 2018 growing season.

“Heavy, flooding rain back in the spring caused some major delays in corn and soybean planting over large portions of the western and northern Midwest,” Anderson said. “July had near- to above-normal precipitation over the majority of the Corn Belt, and August brought generally abundant amounts of moisture as well — except, again, in the southwestern Corn Belt.”

Anderson said the heavy-precipitation trend refused to let up. “September, October and November all featured occasions of heavy precipitation, mostly as rain, which in many areas caused either big harvest delays or losses in either crop quality or actual physical crop loss — or both. And, hurricane damage — notably from Florence and Michael — added to the harsh impact of extreme weather occurrences. Total crop production is large, but there were some big area losses.”

The full impacts of climate change on agriculture production in specific parts of the country are uncertain, but farmers can reduce the negative impacts through different planting decisions, farming practices and technology, the report states.

For instance, in the midterm, offsetting the droughts and a rise in pests and diseases could be biotechnology and gene editing. “Modern breeding approaches and the use of novel genes from crop wild relatives are being employed to develop higher-yielding, stress-tolerant crops.”

RESILIENCY STRATEGY HIGHLIGHTED

To adapt, farmers can alter what they produce, modify inputs, adopt new technologies and adjust management strategies on farms. “However, these strategies have limits under severe climate change and would require sufficient long- and short-term investments in changing practices,” the climate assessment states.

Hohenstein said the report reinforces USDA’s approach to managing climate risk by building resilience on farms. Drought tolerance research, water management and improved irrigation systems, as well as a bigger focus at USDA on soil health, organic matter and water retention, are all areas emphasized by the climate assessment.

“In many ways, the findings of this report reinforce strategies in the department we are taking and with our partners such as the corn growers (NCGA) to get technologies and practices on the ground to help farmers manage these risks,” Hohenstein said. 

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The NCA also looks at the depletion of aquifers from irrigation, especially the Ogallala Aquifer in the Plains. Some parts of the aquifer outside of Nebraska have seen water level declines of more than 150 feet, and water extraction in most of the aquifer far exceeds its recharge capabilities.

Livestock producers are expected to face more economic losses because of heat stress on livestock. Heat stress can affect feed availability as well as reproduction. Dairy cows are especially sensitive to heat stress, the report cited, because it affects both appetite and fermentation.

Wildfires also will intensify, reducing forage on rangelands, much like wildfires have become more frequent in the lower Plains in recent years, wiping out not just tens of thousands of acres of pasture, but also livestock and infrastructure such as fencing.

The report also highlights gaps in research for agriculture and said more private and public research is needed on genetic improvements for crop resiliency. This requires looking at a broader array of crops to improve genetics. More emphasis also is needed to improve nutritional quality and economic implications and not just yield. More research also is needed on the impacts of both beneficial insects and pests.

AG GROUPS SEE DIFFERENT CONCERNS

National Farmers Union has tried to spotlight the risks of climate change with statements and policy resolutions. The group has never been shy about the topic, noted Roger Johnson, president of the National Farmers Union.

“The report makes it pretty clear there is big trouble ahead and we need to start taking this seriously and put some things in place to deal with the existential threat that’s hanging over the world,” Johnson said.

One piece of the assessment that most troubled Johnson was that advances in technology for agriculture, including improved breeding techniques, would not adapt faster than the impact of climate change by midcentury. 

“Climate change is going to be able to overcome whatever technological changes we’re going to be able to provide,” Johnson said. “That’s a pretty stark assessment.”

Agriculture does have the ability to mitigate greenhouse gases through carbon sequestration and perennial crops, as well as reducing methane emissions from livestock and manure. But more understanding is needed on the processes of sequestering carbon and developing mitigation strategies.

The American Farm Bureau Federation has been supportive of initiatives that pay landowners or farmers for storing carbon in the soil. But Farm Bureau’s grassroots members have preferred that climate solutions come from markets instead of government regulation, said Will Rodger, a spokesman for AFBF.

“I’m sure we would be open to paying (farmers) to store carbon,” Rodger said. “The problem our members have had with regulation is that it almost always goes awry and it is typically very inefficient. If you start putting a price on carbon and looking for ways to encourage people to store it, basic economics tells you the folks who are best at it and do it the most efficiently are the ones that would come to the fore.”

The report also cites some of the positive work going on in commodities, including the public-private partnership within the National Corn Growers Association and its Soil Health Partnership for work on climate adaptation including cover crops, conservation tillage and nutrient management to reduce both soil erosion and nutrient losses while increasing organic matter.

Rodger noted the report is a meta-study, and in that sense not much new, though he added, “The definitiveness of the statements being made are certainly stronger than we’ve seen in the past.”

How AFBF members will respond to the assessment and changing climate, through the group’s policy book, is unclear. Rodger added, however, that farmers right now are struggling through a stretch of five years of lower income, farm sales, consolidation and a rise in bankruptcies.

“The idea of another cost being added to the pile just probably isn’t tenable for most of our farmers,” Rodger said.

The full National Climate Assessment can be viewed at https://nca2018.globalchange.gov/…

Chris Clayton can be reached at Chris.Clayton@dtn.com

Follow him on Twitter @ChrisClaytonDTN

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