There’s no way around it – agriculture is both a perpetrator and a victim of climate change. In the United States, agriculture is responsible for 9 percent of greenhouse gas emissions. At the same time, climate change and its resultant higher temperatures, droughts, floods and extreme weather represent perhaps the greatest existential threat to U.S. agriculture in the 21st century. That’s according to a recently leaked final draft of the Climate Science Special Report, the work of 13 federal agencies.
The U.S. Global Change Research Program (USGCRP), mandated by Congress in 1990, is charged with “assist[ing] the Nation and the world to understand, predict, and respond to human-induced and natural processes of global change.” The draft is a follow-up on the comprehensive National Climate Assessment released four years ago. According to the report's authors, there is a “correlation between the expansion of agriculture and the global amplitude of carbon dioxide uptake emissions.” Agriculture is a major emitter of the heat-trapping gases that are responsible for human’s contribution to a changing climate.
A major offender from the agriculture sector is nitrous oxide (N2O), primarily through the use of nitrogen-based fertilizer. N2O has a global warming potential between 265 to 298 times that of carbon dioxide, over a 100-year period. Animal agriculture is the largest contributor to methane (CH4); methane, which is relatively short-lived in the atmosphere, has a global warming potential of 84 to 87 times that of carbon dioxide over a 20-year period.
At the same time, agricultural productivity will be strained by climate impacts. While the report notes that rising temperatures can increase the growing season for certain crops, “there are other consequences to a lengthened growing season that can offset gains in productivity.”
The consequences of warmer temperatures include increased pests, invasive species, droughts, floods and other weather extremes. Additionally, earlier planting due to warmer temperatures can use more available water in the soil, further exacerbating any water shortages in the summer months. Taken together, these factors will impact producers' ability to continue providing a safe and affordable food supply.
These extreme events aren’t far into the future. Farmers and ranchers are already facing unprecedented extremes that impact their livelihoods and production capacity. As one example, historic drought in the Dakotas and Montana have caused cattle ranchers to sell cattle, the USDA to allow grazing on conservation lands, and huge wildfires to spread throughout Montana’s ranches. In Iowa, historic floods earlier this year, which sent sediment and nutrients into the Gulf of Mexico, were followed by historic drought.
To remain profitable going forward, producers will need to become resilient to such extreme events that are becoming all too commonplace. In a stroke of luck, the very means of creating resiliency in the ag sector can also help combat climate change. Techniques such as no-till, cover-cropping, grazing management, buffer strips, and perennials increase soil’s water-holding capacity and boost soil organic matter. By boosting soil organic content, soils become one of the best tools available for combatting climate change, acting as carbon sinks.
A recent study from the Union of Concerned Scientists reports that floods and droughts have cost the United States economy $340.4 billion since 1980, with farmers and ranchers heavily affected. According to study author Dr. Andrea Basche, “soil can offset some of the impacts related to drought and flood.” By shifting some of the least productive, least profitable acres to perennials, farmers can improve soil’s water-holding capacity and boost the soil’s carbon-storing ability. Basche found that perennial crops, cover crops, and improved grazing practices could improve soil’s water infiltration rates anywhere from 35 to 58 percent. Programs in the 2014 Farm Bill are critical in assisting farmers with the transition to these practices.
According to Basche, “we need to be prepared for the next drought or flood that is waiting around the corner.” By taking care of soil, soil will take care of us.
For more information see:
- U.S. Global Change Research Program Climate Science Special Report, Final Clearance 28 June 2017 Fifth-Order Draft (5OD), U.S. Global Change Research Program
- Turning Soils into Sponges: How Farmers Can Fight Floods and Droughts (2017), Union of Concerned Scientists
- Fighting Drought And Flood With Soil Health, Prairie Business Magazine