Climate Change Could Cripple Agriculture

The world needs more food, but temperature, precipitation extremes will make that challenge more difficult.

Published on: Dec 17, 2008

Climate change over the next 30 years will have a major impact on U.S. agriculture says Jerry Hatfield, Director at USDA-ARS National Soil Tilth Research laboratory.

"We have seen a rise in CO2 by about 1.5 to 2% a year and that has lead to higher temps, changes in growing seasons, more variable weather, and increased intensity of storms," says Hatfield, speaking at the Midwest Ag Energy Network Summit held outside Chicago Dec. 15-16. "Soils will become more fragile and will be much more susceptible to erosion, especially if we have these extreme rainfall events over time."

Climate change will result in winners and losers. We're going to find areas in the next 30 years that will get much warmer, much wetter and much drier, he says. The Upper Midwest will become warmer and some areas of the Midwest wetter, but the southwest U.S. will become much drier, leading to major competition for water between cities and agriculture.

How will agriculture be impacted by climate changes in the next thirty years?

• With increased CO2 and temperature, the life cycle of grain and oilseed crops will likely progress more rapidly
• As temps rise, these crops will increasingly begin to experience failure, especially if climate variability increases and rainfall lessens or becomes more variable
• The marketable yield of many horticulture crops such as tomatoes, onions, broccoli or fruits – is very likely to be more sensitive to climate change than grain and oilseed crops
• Climate change is likely to lead to a northern migration of weeds. Many weeds respond more positively to increasing CO2 than most cash crops
• Disease pressure on crops and domestic animals will likely increase with earlier springs and warmer winters, which will allow proliferation and higher survival rates of pathogens and parasites
• Growing zones will change as much as 100 miles from south to north as growing seasons become longer by 2030. Likewise we'll have more extreme weather days in the Midwest with hotter temperatures that could negatively impact animal feeding.

Animals in extreme temperature environments either reduce feed intake or reduce production. Two continuous weeks of blistering high temperatures last summer in California resulted in a $1 billion drop off in milk production, says Hatfield. Hogs and poultry aren't as impacted because they are often grown in a controlled environment, but energy costs to maintain those cooler environments will be a cost factor as we go forward.

A study of climate change on wheat in India, which produces 15% of the world's wheat, shows that temperature changes by year 2050 will cause as much as half that growing area to be classified as heat stressed. India is already just on the brink of self-sufficiency, says Hatfield.

Temperature extremes could hurt pollination, something that needs more research, says Hatfield. Increased temps over the upper Midwest could cause a 4% drop in corn yields but could increase soybean yields 2.5%, he says. He sees a drop of 3.5% in soybean yields in the south where weather extremes will become more common.

"As we look at ag production in the future, climate is going to have a major impact on what happens," concludes Hatfield. "We need to start adapting genetic changes and management practices to account for these changes."