|A connection between climate and agriculture can be found throughout history, and as recently as California's drought earlier this decade. Above, a tomato plant in Woodland, Calif., in 2015, survives by virtue of underground irrigation tubes. Photo: U.S. Department of Agriculture/Lance Cheung. Click to enlarge.|
TipSheet: Farms and Ranches, Possible Cause, Cure of Climate Change
By Joseph A. Davis
The connection of agriculture to climate is an important and overlooked concern that can be found almost anywhere in North America, and it could spark many stories as 2020 unfolds.
Importantly, ag doesn’t always have to be the villain in the narrative. The connection between agriculture and climate is a two-way street. Ag can turn out to be a hero.
Why it matters
We don’t need to go on about why climate change is important. The 2018 U.N. report on 1.5° C warming made it frighteningly clear.
Nor is it a mystery why agriculture is key. It provides a living for many Americans and feeds almost all the rest. But it is also a steward of the nation’s land, water and even air resources.
One example of the ways that farming and ranching affect climate is that agriculture is a significant source — and sink — of carbon dioxide, the principal greenhouse gas. Almost as important is ag’s role in producing — or not producing — methane, another very important greenhouse gas.
These are not new issues: There is some evidence that climate change was a factor in the decline of the Indus Valley Civilization, one of the earliest agricultural civilizations some 2,500 years ago. There is also evidence that land use changes were part of the problem.
You can find the connection in the
devastating California drought of 2011-2017.
And you can find it in the devastating
Mississippi Basin floods of 2019.
You don’t have to go that far back. You don’t even have to go back as far as the drought-based Dust Bowl on the North American prairies of the 1930s. You can find the connection in the more recent devastating California drought of 2011-2017. And you can find it in the devastating Mississippi Basin floods of 2019.
Efforts to combat these problems are not new, either. In the United States, renewed efforts at soil conservation by the federal government were put in place after the Dust Bowl. Today, they are run by Agriculture Department agencies like the Natural Resources Conservation Service. The federal government also spends billions paying farmers to conserve especially important land areas (e.g., wetlands).
Over the past century, there have been many agricultural movements aimed at saving soil and making it healthier. One was “biodynamic” farming. Another that came out of the soil conservation movement was “no-till” or “low-till” farming. Another, better known today, is the “organic” movement, which gets support from the USDA now.
Some effects of agriculture on climate
- Soil can store carbon or it can release carbon. And different agriculture practices determine which of the two it does. Putting animal manure or plant residue into the soil, for example, can enrich it (and sequester carbon). Plowing up and disturbing natural topsoil can otherwise cause it to release carbon.
- Careless soil management exacerbates erosion. The release of soil into waterways takes carbon out of storage.
- Soil can store or release nitrogen. Nitrous oxide, or N2O, is a potent greenhouse gas. Mechanisms of its origin are not completely understood, but much comes from the oceans and the soil. Excess nitrogen fertilizer applied to soil can raise emissions of N2O to the atmosphere.
- Ruminant livestock such as cows produce methane as they digest forage and feed. Methane is a significant greenhouse gas and farm animals are a significant source of atmospheric methane.
- Many farms include woodlots. Trees absorb and store atmospheric carbon dioxide. Harvesting and burning wood puts it back in the atmosphere. Replanting trees restarts the storage process.
Some effects of climate on agriculture
- Global warming will increase weeds, diseases, insect pests and other stresses. These will reduce crop and livestock production in many U.S. agricultural regions.
- As climate change progresses, wet regions may become wetter and dry regions drier. Extreme drought and floods are capable of causing total crop failure, which threatens farmers’ livelihoods and people’s ability to eat.
- As climate change warms the planet, the zones where particular crops can be grown will shift geographically (typically northward in the United States). This will create opportunities in some cases, but will also make impossible the growing of important crops in others.
- Increased CO2 concentrations in the atmosphere may help some plants grow. But this effect is complex and unpredictable — and unlikely to justify the predictions of climate change deniers. Recent studies, for example, suggest that more CO2 causes crops to become less nutritious.
- What are the main crops in your area? How are they grown? What inputs are needed (water, fertilizer, etc.)? What are local tillage practices? Cover crops? Crop rotations? What are the effects of these on greenhouse gas emissions or uptake?
- Do farmers in your area maintain woodlots? How are they managed and harvested?
- How does farmland and ranchland in your area figure in livestock and dairy operations? Do animals graze in open fields? How is manure managed?
- Are there any “organic” or “biodynamic” farms in your area? Talk to the owners and find out how they view climate impacts.
- Find out about federal payments for conservation programs in your area. Even if federal data about specific farmers is hard to access, you should be able to learn a lot by looking around and asking around. Then talk to the farmers. And their neighbors.
- Are there feedlots (confined animal feeding operations) in your area — not just for cattle, but also for hogs, chickens, etc. What happens to the manure and other waste? Is anyone capturing it and digesting it for methane? How is that working out?
- What levels of funding will be in the coming year’s (fiscal 2020) federal appropriations for programs that reduce the climate impacts of agriculture?
- What proposals are candidates for the presidency making that will promote positive (and lessen negative) impacts of agriculture on climate?
- The “Climate Change and Land” report by the Intergovernmental Panel on Climate Change, which came out in August 2019, is a comprehensive road map to the issue.
- “Creating a Sustainable Food Future,” by World Resources Institute (July 2019), takes a global perspective, with focus on food security.
- Fourth National Climate Assessment, U.S. Global Change Research Program, Nov. 2018. See Chapter 10 on agriculture.
- If you want local angles, check in with your local USDA Cooperative Extension office.
Joseph A. Davis is a freelance writer/editor in Washington, D.C. who has been writing about the environment since 1976. He writes SEJournal Online's TipSheet and Reporter's Toolbox columns. Davis also directs SEJ's WatchDog Project and writes WatchDog Tipsheet, and compiles SEJ's daily news headlines, EJToday.
* From the weekly news magazine SEJournal Online, Vol. 4, No. 38. Content from each new issue of SEJournal Online is available to the public via the SEJournal Online main page. Subscribe to the e-newsletter here. And see past issues of the SEJournal archived here.