The connection between livestock farming and climate change has never been more clear. Raising animals for food uses extraordinary amounts of water, causes deforestation and contributes heavily to greenhouse gas emissions, making the practice of farming animals severely damaging to the climate and overall planetary health. Research suggests that a number of shifts, including dietary change, can help bring down food-related climate emissions.
How Does Farming Livestock Affect Climate Change?
Raising animals on farms for food production takes a tremendous toll on the health of the environment. Animal agriculture is a contributor to greenhouse gas emissions, including nitrous oxide and methane, water pollution and the destruction of forests and other wild areas that help to regulate the planet’s atmosphere.
How Does Livestock Farming Contribute to Greenhouse Gas Emissions?
The two main greenhouse gasses produced by the practice of rearing farmed animals are methane and nitrous oxide. Globally, raising animals for food contributes at least 16.5 percent of greenhouse gas pollution.
Nitrous oxide is almost 300 times more potent than carbon dioxide when measured on a scale of 100-year Global Warming Potential. A number of farming practices add to nitrous oxide pollution, including soil management practices such as the application of synthetic and organic fertilizers to grow food both for people and animals, handling manure from raising animals for food and burning crop residues. According to EPA figures, these practices account for 74 percent of all nitrous oxide emissions from the United States.
Accounting for about 11 percent of all U.S. anthropogenic greenhouse gas emissions, methane has an impact 25 times greater than carbon dioxide. The agriculture sector is the largest source of methane emissions in the United States, by EPA estimates.
Livestock Methane Emissions
Ruminant animals commonly raised for food, including cattle, goats and sheep, emit methane as they digest their food through a process known as enteric fermentation. During this process, microbes in the animals’ digestive tracts decompose and ferment plant parts such as cellulose, starches, sugars and fiber. This process is incredibly effective — ruminants like cows can eat plants and crop waste that humans can’t thanks to their largest stomach chamber called the “rumen” — but a byproduct of this process is the toxic pollutant methane, released into the atmosphere primarily through animal burps.
Methane from livestock manure is another source of emissions, especially significant from concentrated animal feeding operations, or CAFOs, of hogs and dairy cattle that store manure as a liquid.
How Does Deforestation Affect Climate Change?
Forests and other wild areas of land like savannas play an important role in storing carbon that would otherwise be released into the atmosphere. Unfortunately, forests and other natural ecosystems across the globe are being destroyed to make way for urban expansion, logging, mining and agriculture.
The largest forest on earth is the Amazon rainforest, which covers 2.72 million square miles and stretches into nine different countries. Considered one of Earth’s most important terrestrial carbon reserves, the Amazon stores an estimated 123 billion tons of carbon.
In addition to the role these ecosystems play storing carbon, forests also stabilize soil with their roots, preventing erosion. When forests are destroyed the soil itself is also able to hold less water, increasing the likelihood of flooding to nearby communities. Deforestation in some areas can also lead to an increased likelihood of drought as the water cycle is disrupted.
The largest driver of deforestation in the Brazilian Amazon rainforest is animal agriculture, which has been tied to 75 percent of coverage loss. Loggers and farmers in the Amazon cut down trees to create ranches where cattle and other farmed animals can live and graze, and also to create fields for growing corn and soy to feed farmed animals.
When forests are destroyed, whether by fire or converted for growing animal feed, the carbon dioxide once stored is released into the atmosphere. Perhaps even worse, these actions also deprive the land of its ability to store carbon, described by researchers as a lost ‘opportunity cost’ for climate action that can only be recovered if the land is reforested or rewilded.
How Does Eating Meat Affect Climate Change?
Food-related greenhouse gas emissions come from a variety of sources throughout the animal farming supply chain. Sources include burps and manure from the animals themselves, the storage of their manure, the use of fertilizer on the fields used to raise them, fuel for transport, the land used to feed and raise them and the heating and machinery required for animal agriculture production.
Water Usage and Pollution
Feeding and raising animals as livestock uses far more water than growing crops like soy or lentils. Beef production requires 15,415 liters per kilogram of meat, 112 liters per gram of protein and 153 liters per gram of fat. One third of all the water used by the animal agriculture sector goes toward the production of beef. Another 19 percent goes to dairy cattle for the production of milk and other dairy products.
Livestock farming also pollutes waterways, disproportionately impacting Black and Indigenous communities, as well as other communities of color. This pollution comes mostly from manure pits or lagoons created to hold the waste of the thousands of animals housed on factory farms. When pits leak or overflow, the nitrogen and other contaminants in the manure pollute local water sources, causing or exacerbating numerous health problems in the surrounding communities. To avoid overflow, farmers often apply too much manure to fields, which also leads to pollution runoff.
How Does Climate Change Affect Livestock?
The production of meat and other animal products is a large contributor to climate change, which in turn makes life worse for the millions of animals living on factory farms.
A central feature of industrialized agriculture is its efficiency, achieved by packing thousands of animals together into a relatively small area to feed them for slaughter. The tight quarters in which these animals are living, coupled together with rising temperatures, leads to metabolic disruptions, damage to the body’s cells and immune suppression, which in turn make disease, infection and death more likely.
Why Are Some People Saying Beef Production Is Only a Small Contributor to Emissions?
Some proponents defend beef by pointing to the livestock industry’s increasing capacity for producing more meat from each cow slaughtered. Since the 1970s, the number of cattle needed to meet the demand for beef in the United States has fallen by about 50 million.
The industry has made this shift thanks to intensive breeding resulting in cows that grow faster and larger than their parents and grandparents. The 90 million cattle that are being raised to meet the demand for beef today, for example, are supplying more meat per animal than 140 million cattle were in the 1970s.
Fewer cattle does mean lower greenhouse gas emissions but industry efficiency alone is not enough to reach the climate targets set out in the Paris Climate Agreement to limit global warming. Climate research points to deploying a number of simultaneous strategies to bring down food-related emissions, including dietary change in countries that currently consume the most beef. In the U.S., for example, Americans eat four times more than the global average.
Another common argument given by those in the camp playing down beef emissions is that cattle being raised for beef directly contribute only 3 percent of U.S. greenhouse gas emissions. That percentage leaves out climate impacts from land use, like deforestation for grazing and growing feed.
Will Eating Less Meat Help Reduce Climate Change?
Eating less meat is one of the most impactful ways to reduce our personal or household contribution to climate change. In fact, plant-based foods have a carbon footprint 10 to 50 times smaller than animal-derived products on average. Choosing to eat vegetarian also decreases water consumption by between one-third and one-half compared with a diet that contains meat. Wasting less food is another powerful form of household climate action.
Future Action: Food System Transition
Industrial animal farming is detrimental to ecosystems and communities, as well as to the health of the planet on which we all depend.
One powerful yet challenging form of climate action is food system change. To begin the work of shifting food systems away from its current central focus on animal proteins, several advocacy groups are working with farmers to transition out of the livestock industry. One example is Transfarmation, an organization that works with poultry and hog producers to grow crops like mushrooms and hemp rather than raise animals for food. These efforts are just one small part of the much-needed collective transition to a more plant-rich food system.