Agriculture and Greenhouse Gas Emissions

What's the connection between agricultural and greenhouse gas emission? Agriculture and Greenhouse Gas Emissions

Ever buy a box of cereal, a bag of apples or a gallon of milk and think, “I wonder how the production of this product has impacted the Earth?” We may not think these words verbatim, but something similar may come to mind for many of us—something that shows we care about how food production impacts the environment. While many trips to the grocery store start with a hunt for a great bargain for food that will fill household bellies, many trips also involve consideration of the environmental impacts of our purchases. For instance, a 2020 IFIC consumer research survey found that most people (more than 70%) are concerned about climate change, and over half (52%) of those who are concerned said their concerns sometimes impact their food and beverage purchases. Nearly one in five (19%) said these concerns always impact their purchases.

A background on greenhouse gases

When we think of environmental concerns, the sustainable use of natural resources such as water, energy and soil may come to mind—and so too does the emission of greenhouse gases. Greenhouse gases are defined as the gaseous compounds in the Earth’s atmosphere (such as carbon dioxide) that absorb infrared radiation, trap heat and contribute to the greenhouse effect (which refers to the warming of the Earth’s surface and atmosphere). The main greenhouse gases are water vapor, carbon dioxide (CO2), methane (CH4), ozone (O3), nitrous oxide (N2O) and chlorofluorocarbons (CFCs).

With increased levels of greenhouse gases in the atmosphere come resultant increased temperatures globally. The warming of the Earth’s atmosphere, termed “global warming,” is causing our climate to change. New weather phenomena like melting glaciers, more intense storms, more frequent forest fires, and the rising of global sea levels all reflect our changing climate.

Many news stories and scientific articles have reported on the importance of monitoring the concentration of greenhouse gases in the atmosphere (mainly carbon dioxide (CO2)) as well as how greenhouse gas levels rising over a span of many years has had deleterious impacts on the environment. Today, the concentration of CO2 in the atmosphere is over 40 percent higher than it should be. Notably, a large number of environmental scientific experts agree that climate change is happening and that humans are the cause.

Greenhouse gases and farming

The top three greenhouse gas–emitting groups globally are China, the European Union and the United States—combined they contribute 41.5% of total global emissions. Efforts to decrease emissions in these sectors of the world are paramount in decreasing overall gas emissions and the impacts of the greenhouse effect.

Here in the United States, there are six major contributors to greenhouse gas emissions: Transportation (28% of total emissions), electricity production (27% of total emissions), industry processes and burning fossil fuels (22% of total emissions), land use and forestry (12% of total emissions), and agriculture (10% of total emissions). According to the United States Environmental Protection Agency (EPA)’s 2020 U.S. Inventory of Greenhouse Gas Emissions and Sinks report, total emissions from the energy, industrial processes and product use, and agriculture sectors have all grown. Greenhouse gas emissions from agriculture have increased by 10.1 percent since 1990. As the EPA notes, “drivers for this increase include a 7 percent increase in N2O from management of soils, along with a 58.7 percent growth in combined CH4 and N2O emissions from livestock manure management systems.”

The total ten percent of emissions attributable to agriculture can be basically broken down in the emissions of nitrous oxide (N2O), methane (CH4), and carbon dioxide CO2. According to the EPA, specific activities that contribute to N2O emissions from agricultural lands include the application of synthetic and organic fertilizers, the growth of nitrogen-fixing crops, the drainage of organic soils, and irrigation practices. Livestock contribute to emissions via enteric fermentation, which means they produce CH4 as part of their normal food digestion processes. An additional contribution from livestock is linked to manure management, which contributes to both CH4 and N2O emissions. Different manure treatment and storage methods affect how much of these greenhouse gases are produced. Smaller sources of agricultural emissions include CO2 from liming and urea application, CH4 from rice cultivation, and CH4 and N2O from burning crop residues.

Efforts to decrease emissions

While there is much work to be done to reduce emissions from the above-mentioned sectors, there are various activities in progress to reduce emissions from land and crops, livestock, and manure management. For instance, farmers are fertilizing crops with enhanced nitrogen monitoring—too much nitrogen can contribute to higher nitrous oxide emissions without enhancing crop production. For livestock, increasing pasture quality helps to reduce the amount of methane emitted per unit of animal product. Additionally, there are various efforts underway to capture methane from manure decomposition in order to produce renewable energy.

Agricultural demands across the globe have increased in recent years due to our growing population, which has added many environmental stressors to our planet. It is important that food producers, food industry professionals and consumers set their sights on actions to help alleviate these stressors—including decreasing greenhouse gas emissions. We look forward to seeing more efforts in play as we strive to sustain our natural resources and preserve our environment—and ultimately make it better!