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Experts: Earlier spring, hotter summers ahead

posted: December 26. 2017 07:13a CST
by / Jim Massey, Editor |

WISCONSIN DELLS — Scientific evidence shows the climate is changing and humans are contributing to the warming temperatures, but yet a majority of farmers believes changes in the weather are due to normal climatic phenomenon, attendees at the UW Discovery Farms Conference were told Dec. 12.

Paul Mitchell, a professor in the UW-Madison Department of Agricultural and Applied Economics, said 68 percent of 1,000 farmers surveyed in four states — including Wisconsin — said they believe the warming temperatures are due to normal weather changes rather than human activity. Only 38 percent believe human activity is changing the climate, Mitchell said.

“It’s not about the science or the evidence, it’s the way you were raised,” Mitchell said when explaining farmers’ viewpoints. “We all want things to be true, regardless of the evidence. Arguing with people using evidence that contradicts their beliefs usually makes people more set in their beliefs.”

Chris Kucharik, a UW-Madison professor in the Department of Agronomy, said most farmers don’t think they’ve changed the management on their farms because of climate change, but he can show data that proves otherwise.

For example, in Wisconsin, farmers are planting corn about two weeks earlier than they did in the 1970s, primarily due to the earlier onset of spring. Seed technology has helped farmers plant earlier, too, but warmer temperatures earlier in the spring have been a major factor in allowing farmers to plant earlier, Kucharik said.

Kucharik presented some startling data as to how climate change might affect agriculture in the future.

By the middle of this century, temperatures are likely to warm by another 3 to 4 degrees, Kucharik said, and the growing season could expand by one to two weeks.

On average, Wisconsin experiences about nine days above 90 degrees each year. In 2012, there were 39 days above 90, and that will likely be closer to the average 50 years from now.

“We’re going to get warmer, a bit wetter, and the frequency of very heavy rainfall events is likely to go up,” Kucharik said.

He predicted a decrease in extremely cold temperatures, a trend which he said is already occurring. There are places in southern Wisconsin that will no longer get below zero, he said.

While most people would assume that a longer growing season would mean higher yields, those two things don’t necessarily correlate, Kucharik said.

“The additional heat during the growing season is not good for increasing crop yields moving forward,” he said. “Cooler and wetter summers tend to favor larger yield gains. The yield trend line will start to get knocked down depending on how much warming occurs.”

Kucharik said he doesn’t expect the trend to earlier planting to continue forever.

“If we end up planting in February, that means the climate has totally gone off the rails,” he said. “I don’t think this will happen.”

Additional summer heat will mean more heat stress on livestock, too, Kucharik predicted.

“By the end of the 21st century, the combined affect of heat and humidity could push us into the emergency category almost all the time (during the summer),” he said.

Extreme precipitation events could cause more soil erosion and nutrient loading to waterways, Kucharik said.

“If anyone can figure out how to stop water from moving across the soil surface, let me know — we’ll be really famous,” he said.

Kucharik said adaptation in agriculture to climate change is entirely possible, as long as the change is not rapid.

“I’ve got a lot of hope and think there are a lot of things that can be done,” he said.

He suggested that more conservation tillage and cover crops will help stem the tide of increased erosion, while an increase in perennials on the landscape would also help. Farmers should also consider using less inorganic fertilizers and support research to identify technology that does and doesn’t work.

Mitchell said farmers have a long history of adopting technologies and practices that help them adapt to a changing world. He believes they can adapt to future changes in the climate as well.

About two-thirds of Midwest farmers surveyed in 2012 believe adapting to changing weather is a farmer and private-sector problem, and not a public-sector problem. About one-third of farmers think Extension and state agencies can help farmers adapt.

Adaptation strategies that farmers should consider include increasing crop insurance, diversifying crops and modifying land leases, Mitchell said.

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