The USDA has released two comprehensive reports on expected effects of climate change on agriculture and forestry. The reports --Climate Change and Agriculture: Effects and Adaptation and The Effects of Climate Variabilityand Change on Forest Ecosystems: A Comprehensive Science Synthesis for the U.S. Forest Sector -- will be part of the upcoming National Climate Assessment.

Access both reports here.

The reports’ predictions are not comforting with claims that increases in temperatures, atmospheric carbon dioxide, altered precipitation patterns and increasing extreme weather events will definitely influence agriculture. And while some crops may actually benefit and expand into areas once impossible to grow in, the overall picture is not rosy. Management of weeds, insect pests, and diseases will gain even more importance in coming years.

“The National Climate Assessment is produced every four years,” said Bill Hohenstein, Director of the Climate Change Program Office in USDA’s Office of the Chief Economist during a Feb. 7 interview with Farm Press. “That is done to meet a statute called the Global Change Research Act, which was passed in 1992.

“So, government-wide, the United States puts out a comprehensive synthesis of climate change science. The last one came out in 2009. This one – out for public comment, right now -- will come out (this year). Generally, it takes a couple of years to pull a report like this together.”

While the topic of climate change remains controversial, climate change proponents do include farmers. In a letter to Congress released shortly after the USDA reports, National Farmers Union President Roger Johnson said, “Mitigating and adapting to climate change is of significant concern to our membership and will be a defining trend that shapes the world. National Farmers Union has long played a leadership role in the agriculture community in regard to addressing the challenge of climate change. Our members are acutely aware of changing weather patterns and extreme weather events that affect their operations.”

Among Hohenstein’s other comments:

Regarding findings on row crops…

“The report does go through the major commodity crops and what can be expected.

“The other part of the story that’s very important is what will happen regionally. How is climate change expected to play out in, say, the Southeast, the Southwest, or the Northeast? The implications regionally are expected to be different.

“We’re obviously worried about higher temperatures and their effects on cropping systems, moisture. But there are a variety of implications. Especially over the next 20 to 30 years, there will be a mix of consequences for agriculture.

“One is we expect longer growing seasons. For some crops, ranges within the United States will expand. Also, the effects on rainfall won’t be evenly distributed across the country. Some regions will see an increase in rainfall and moisture availability.”

On the effects on the livestock sector…

“The report has a section on livestock production. Many of the effects are a function of temperature.

“Again, you see two types of impacts. One is the negative effects of low winter temperatures. In the summer, there will be greater heat stress and with that comes losses in production and sometimes mortality.”

Forestry impacts

What about infrastructure? Did you look at how river traffic might be impacted?

“We didn’t in any detail.

“However, there was a report put out by the Department of Transportation looking at the effects of climate change on transportation systems in the country. One of the things they looked at was the importance of things like the Mississippi River for grain transport. They looked at how areas of the Delta might be affected by sea level rise and how that could hit ports and some of the low-lying, major highway arteries.”

See DOT map of projected impacts here.

What about forestry? Are you predicting more wildfires? More difficulty controlling insects?

“Certainly both of those things.

“Forestry systems are less adaptable than the agricultural systems. Within agriculture, you can plant cultivars of crops, change the timing of when you’re growing a crop. There’s just a lot more capacity to adapt to changes.

“That isn’t true of forestry systems. Once you have a forest in place, that’s a long-term investment.

“There are three things we’re particularly concerned about in terms of climate change and forest resources.”

  • The effect changes in rainfall will have on moisture availability for growing.
  • Changes in pests.

“In some ways the changes in pests will be driven by the forest’s health. But another driver will be the fact of warmer temperatures. Some of the pests currently being knocked back during the winter will be able to get a jumpstart.

“Some pests like the pine beetle are a real concern. We used to see one life cycle from that pest during a year. Now, there are two. Increasing temperatures will only increase that pest pressure.”

  • Fire.

“The increases in pressures from drought, pests and temperatures will make forests more vulnerable to fire. We project that there could be a doubling of the annual rate of fires by 2040.”

Any suggestions about what the USDA response should be?

“The reports integrate the effects of climate change as well as work on adaptation, or how we need to respond. There is a lot of information about how to make our natural resources, whether agriculture or forestry, more resilient to climate change and variability.

“A lot of those investments will have pay-offs today. That includes things like improving the water-holding capacity of soils. That makes farmland more resilient to drought. Improving forest health has benefits today and also in the future with the changes we expect.

“Many of the practices we recommend in terms of adaptation responses to climate change turn out to be smart conservation practices.”