Publication
Reducing carbon footprints of agriculture and food systems
Authors
Rattan Lal, Distinguished University Professor of Soil Science, School of Environment and Natural Resources (SENR)
Quick Take
As the climate continues to warm, the days of current agricultural systems are numbered, researchers say. Changes in the climate can lead to scarce or contaminated water, degraded soil, and destroyed biodiversity. With the food system contributing a third of greenhouse gasses, the industry will either need to start changing its methods now, or a new, harsh environment will make growing food a major challenge, they say.
To understand how different activities impact the environment, researchers study the natural resources that humans can change and degrade. Some of these resource indicators include soil, water, atmosphere, and biodiversity. The quality of all of these factors make up our “ecological footprint,” a measure of humanity’s effects on the entire lifecycle of an area.
When scientists consider ecological footprint from the perspective of greenhouse gas emissions, they call it “carbon footprint.” Carbon footprint measures how human activities contribute to climate changes. A larger carbon footprint means more insulating gasses are entering the atmosphere. Many environmental conservation studies are focused on how we can reduce the carbon footprint of daily life.
A recent review conducted by Dr. Rattan Lal, distinguished professor of soil science at The Ohio State University’s School of Environment and Natural Resources, analyzed the environmental issues posed by agriculture and the food system. Lal also goes over potential solutions and strategies for reducing its carbon footprint, including standardizing environmental impact measurements, shifting land use, and eliminating food waste.
Review Findings
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Differences in how researchers think about resource use and how they compute their results has a strong effect on estimates of carbon footprint. Making informed decisions depends on having accurate and consistent data to work with. The review notes that researchers should prioritize using international standards when identifying elements that contribute to emissions and numerically measuring their effects.
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Carbon sequestration refers to the natural process of capturing atmospheric carbon and storing it in plants or the soil. For example, when a plant takes in carbon dioxide during photosynthesis, it keeps the carbon in land ecosystems for a long time. Lal notes that using this strategy gives the agricultural industry an opportunity to minimize the amount of carbon escaping to the atmosphere and thus contributing to climate change.
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Conservation agriculture is a farming system that aims to preserve land through minimizing disturbance, permanently covering land with plant material, and diversifying crops (intercropping/crop rotation). Use of this system can successfully conserve soil, water, energy, and time, the review notes. Agricultural carbon footprints can be greatly reduced by switching conventional tillage to conservation agriculture. Practices specific to sites and crop species can dramatically decrease carbon footprints for those areas. Researchers can perform more in-depth studies for common crops and locations to uncover more efficient, climate-friendly methods.
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Animal-based food products make up 70-75% of the carbon footprint in a person’s diet. However, some products (like poultry or fish) have lower carbon footprints than those of red meat. Livestock animals use large areas of land and require their own separate food sources. Animals with four-chambered stomachs such as cows, sheep, and goats use a process called enteric fermentation where the microbes in the animal’s digestive tract break down food and produce methane as a byproduct. Methane contributes significantly to livestock greenhouse gas emissions. To protect the environment, researchers recommend shifting our diet proportions away from mostly animal products (especially beef) and toward plant-based foods.
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The world wastes 1.4 gigatonnes (2.8 trillion pounds) of food each year. Of that waste, 931 megatonnes (2.05 trillion pounds) of waste comes from retail, food services, and households—enough to feed 820 million people experiencing food insecurity. America wastes the most food, with 30-40% of the food supply thrown out yearly. Wasting food also wastes the energy, nutrients, and water that went into providing that food. Researchers note that by eliminating food waste, we can reduce production costs, lower resource use and emissions, and possibly feed more people.
Citation
Lal, R. “Reducing carbon footprints of agriculture and food systems.” Carbon Footprints, April 2022. Volume 1, No. 3. http://dx.doi.org/10.20517/cf.2022.05