What Can Farmers Do About Climate Change?
by Martin Kleinschmit, Center for Rural Affairs
Farmers and agriculture in general may be "betting the farm" if nothing is done to reverse the trend of increased concentration of greenhouse gasses in the atmosphere.
Greenhouse gases - carbon dioxide, methane, and nitrous oxide - combine in the atmosphere to form an insulating layer that traps solar radiation and keeps the earth warm and livable. But, like most things, there can be "too much of a good thing." As concentrations of these greenhouse gasses increase, more heat is trapped and the earthís atmosphere warms, causing weather and climatic patterns to change.
If El Ni§o - a pool of warm water that moves into the Pacific Ocean because of a decrease in the westerly trade winds - can change the movement of the jet stream and affect precipitation patterns, isnít it likely that increases in temperature and moisture will also affect our climate?
It is not realistic to expect that global climate change will lead to a simple increase in temperatures with no related consequences. What should concern farmers is the more likely scenario of extreme weather conditions that will severely affect agricultural production and profitability. Scientists believe that global climate change will result in colder, wetter winters and springs followed by hotter, drier summers. Storms will be more severe and less predictable. Precipitation may increase due to more water vapor in the air, but increased evaporation due to higher temperatures in the summer will probably result in less usable moisture.
What can farmers and ranchers do to mitigate the effects of global climate change? Less risky, more diverse farming systems may be an answer. Risk-avoiding practices might include:
Increasing soil organic matter allows the soil to hold more moisture, making it resistant to drought conditions and better able to hold nutrients for plant growth. USDA research shows that a block of dry soil 6" thick containing 2% organic matter can only hold about 1-2" of moisture; that same soil with 4-6% organic matter will hold 4-6" of moisture. So, increased organic matter translates into more moisture available to the roots and more soluble nutrients in the root zone.
Increasing soil organic matter not only helps farmers avoid the risks associated with climate change, but it also can help reduce the increase in carbon dioxide in our atmosphere. Soil organic matter captures carbon dioxide from the air and holds, or sequesters, it in the soil. Unfortunately, carbon sequestering can not possibly keep up with the huge amount of carbon dioxide emitted into the atmosphere from automobiles and other sources. Still, building soil organic matter improves soil resilience and it can help address the problem of carbon dioxide emissions.
Livestock management practices can make a difference in the amount of methane released into the atmosphere. Animals produce about 15 percent of all methane emissions, most of it from the unique digestive process by which ruminants break down carbohydrates and proteins in grass. Generally, the higher the digestible energy in cattle feed, the lower the rate of methane emissions.
Methane is also produced by manure, primarily when it decomposes anaerobically (in the absence of oxygen). Water-based waste management systems such as the anaerobic lagoons and storage pits used in large-scale livestock facilities are particularly potent methane producers. Overall, beef and dairy cattle and hogs in the U.S. produce about 3.7 million tons of manure methane, nearly half of it from the small percentage of animals raised in large facilities with lagoon waste management systems.
Nitrogen fertilizer is a major source of nitrous oxide emissions. North American (principally U.S.) agriculture contributes from about one-third to one-half of the global fertilizer-derived emissions of nitrous oxide. This is not only because we use more nitrogen on more acres, but also because we use a disproportionate amount of anhydrous ammonia, which has a high emission rate - about 2.7% compared with other fertilizer types which run from 0.07% to 0.44%.
U.S. greenhouse gas emissions related to agriculture could be reduced by roughly one-fourth through improved nitrogen fertilizer management (without yield losses), by another 10% through better manure management, and by another 8% through improved crop rotations. These steps would reduce nitrogen fertilizer-derived emissions by a total of 40-45% below current levels.
Agriculture relies more on the climate to survive than any other aspect of the economy. Policy changes need to be put in place to avoid an agricultural disaster and encourage reductions in greenhouse gas emissions. Not having a plan is not going to make the problem go away.
For more information on the subject of agriculture and global climate change, the report Mares Tails and Mackerel Scales is available for $12 from the Center for Rural Affairs, Box 406, Walthill, NE 68067, 402-846-5428.