Arctic Warming's Ag Impact Studied

Scientists: Effects of Warming Arctic on Corn Belt Weather Unexpected

Todd Neeley
By  Todd Neeley , DTN Staff Reporter
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Though climate models predicted Corn Belt regions would become hotter and drier, in the early 20th century, the climate became "more favorable for corn production in the middle latitudes, and it has become wetter," Marty Hoerling, a climate scientist with the physical sciences division at NOAA, said. (DTN file photo by Elaine Shein)

LINCOLN, Neb. (DTN) -- Many scientists believe Arctic warming and loss of sea ice in part led to last winter's so-called Polar Vortex and weather patterns responsible for dumping record amounts of snowfall in the Northeastern United States.

Two scientists said during a University of Nebraska workshop Tuesday on the Arctic melting that those changes so far have had little effect on Corn Belt agriculture. As the climate has warmed, they said, Midwest agriculture has benefitted.

Climate researchers presenting at the Nebraska Innovation Campus say they have been surprised Corn Belt weather has not reacted to what they say is a warming planet and subsequent harm to yields. In fact, if anything, they said any change in climate has resulted in milder and wetter Corn Belt summers -- both of which are beneficial to crop yields, especially corn.

Marty Hoerling, a climate scientist with the physical sciences division at the National Oceanic and Atmospheric Administration, or NOAA, based in Boulder, Colorado, said although there is no reliable ground-level temperature data in the Arctic, overall warming is "affecting a larger surface warming of the Arctic than the rest of the world, and that has accelerated because sea ice is melting."

Models and available data on the ice melt show Arctic ice decline in the late-summer months is averaging about 13% per decade, Hoerling said, estimating more than 50% of that is human-caused.

"Probably not all we're seeing is human induced," he said, attributing much of the melting to "natural variability" which he says still "rules the roost."

What's more, Hoerling said, potential weather links to "Arctic amplification" in the middle latitudes including the Corn Belt is "weak."

Hoerling said Arctic temperatures have averaged 1 degree to 2 degrees Fahrenheit warmer between 1980 and 2010. "The pace is much more dramatic at this time," he said.

Though climate models predicted the Corn Belt regions would become hotter and drier, Hoerling said that in the early 20th century, the climate became "more favorable for corn production in the middle latitudes, and it has become wetter.

"It looks like nothing like the story we hear," Hoerling said. "It has been a climate surprise."

NORTHEAST WINTER

Judah Cohen, principal scientist for the Climate Analysis Group in Newton, Massachusetts, said last year's record snowfall in the Northeast likely is caused by warming in the Arctic. Snow cover has been on the increase since 1988, he said, while Arctic ice has been decreasing since 1998.

"The snow cover is unexpected," Cohen said, based on climate models predicting changes in climate. "Last year was the highest snow cover on record for the Northern Hemisphere. It is especially surprising and not expected. When I was in graduate school, we thought snow cover would have been on a death spiral -- very unexpected."

What has occurred in the middle latitudes, including Corn Belt states, he said, is milder winters have become more common as the Arctic warms from October to March. "We tend to get more extreme weather in mid-latitudes," Cohen said.

Those events include more frequent heavy rain events in the Midwest.

Cohen said the unexpected effects of a changing climate mean scientists need to better hone scientific models and expand research.

"I think there are things we don't understand," he said. "We've reached a temperature where snow should be slowing and it's not."

HEALTHY SOILS

Jerry Hatfield, research plant physiologist at the National Laboratory for Agriculture and the Environment at the USDA's Agriculture Research Center in Ames, Iowa, said farmers can best prepare for expected wide weather variability by taking steps to improve soil.

Healthy soils will allow for better drainage following heavy rain events, he said. If northern areas of the Corn Belt become warmer, Hatfield said, it means more corn acres will be planted to poorer soils.

"We're back in a period of great uncertainty in corn and soybeans," he said.

"When it rains, it pours. Average precipitation is going up. Days of heavy precipitation are going up. The function of the soil is to infiltrate water. The higher the temps, yields come down because of water stress. These are all changing pieces of the puzzle.

"Producers are becoming increasingly concerned about variability of production and whether they can make a profit. We see questions asked, 'how am I going to cope with changes?' What we see is lower yields, and risk of crop failure gets larger and larger."

When it comes to many areas of Iowa in particular, Hatfield said he has worked to educate producers on how seasonal variability affects the way their soil performs.

"They manage their fields as if they have high-quality fields," he said. "We've had to show them soil behaves differently relative to seasonal weather."

If Corn Belt temperatures rise, many producers will be shifting acres into lower-quality soils, Hatfield said. He said higher variability in weather conditions already has affected the cost of doing business.

For example, when it comes to crop insurance claims on corn in the Midwest, Hatfield said 55% of those claims are related to excess moisture and drought. Since 1989, he said, there has been some $12 billion in claims paid out as a result.

"These are in our realm to change," he said.

This past year, Hatfield said, some parts of Iowa lost some 100 tons of soil per acre to erosion. Though it runs contrary to what many farmers in Iowa have done for ages, he said producers need to begin to look past traditional corn-soybean rotations.

"If we want a more resilient system, we need to be more diverse in crops," Hatfield said. "That flies in the face of what we're doing."

Todd Neeley can be reached at todd.neeley@dtn.com

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Todd Neeley