Factory Farming: A Recipe for Disaster for Animals & Our Planet

At any given moment, there are over 1.6 billion chickens, pigs, cows and other animals being raised for food across the United States, and over 10 billion farm animals are slaughtered annually. These animals are overwhelmingly raised on what the Environmental Protection Agency (EPA) and the agriculture industry call Concentrated Animal Feeding Operations (CAFOs). We call them factory farms. Each CAFO may hold tens or even hundreds of thousands of animals sealed inside in extremely crowded conditions.

In addition to causing immense animal suffering, raising this many animals in these conditions does enormous environmental damage. Globally, animal agriculture represents 14.5% of all human-caused greenhouse gas emissions. While much discussion is devoted to methane from cows, the massive feed-crop production and manure associated with all CAFOs—cattle, pork and poultry—are significant contributors to air and water pollution as well as climate-warming emissions.

  • In the U.S., animals on CAFOs produce an estimated 885 billion pounds of manure each year, none of which is treated or regulated by a government agency.
  • Nearly 50% of corn and 70% of soy grown in the U.S. is produced to feed animals raised in CAFOs. Those crops consume vast quantities of water and require enormous amounts of fossil fuels and pesticides, all of which adds to the environmental footprint of the final product.

Despite its heavy environmental impact, industrial animal agriculture is largely exempted from federal and state air and water pollution regulations that apply to other major industries, just as it is exempt from almost all state and federal animal-protection laws.

With the evidence mounting about this industry’s cruelty and its connection to climate change, the ASPCA is working alongside environmental advocates to replace factory farming with higher-welfare, pasture-based animal farming and more plant-based alternatives. Learn more:

The Water, Air, and Climate Impacts of Factory Farming

Factory Farms Pollute Our Water

In traditional farming, animals distribute their waste as they move, which can be beneficial to the land. With industrial operations, tens of thousands of animals are housed in sheds or pens, which, in addition to causing frustration, stress and painful ailments for animals, leads to massive build-ups of manure. Every minute, nearly 7 million pounds of excrement are produced by animals raised on CAFOs in the U.S.

Unlike human waste, manure from CAFOs is not treated and typically gets flushed into underground pits or lagoons that are several acres wide. It is stored there until it is applied as fertilizer on fields. But the quantity of waste produced on factory farms cannot easily be absorbed, resulting in over-application and runoff of the manure—and all of the chemicals, toxins and bacteria it contains—into local waterways. It is also common for the pits or lagoons to leak, break or overflow, contaminating groundwater. Animal agriculture is the leading polluter of U.S. rivers and streams, the second-largest source of wetlands contamination, and the third-largest source of lake pollution.

As a result, CAFOs have severe impacts on aquatic health as excessive nutrient concentrations from manure, such as nitrogen or phosphorus, can make water uninhabitable or cause harmful algal blooms. Rural communities rely heavily on groundwater wells for drinking water, and the Environmental Protection Agency’s 2000 National Water Quality Inventory found that 29 states specifically identified CAFOs as contributing to drinking water quality impairment. Cleanup expenses from CAFOs have cost municipal water systems over $1.1 billion over the past 10 years.  

Factory Farms Are Water Hogs

While pollution is a more visible problem, the immense water demand from CAFOs has alarming environmental and community impacts as well. Globally, agriculture uses more freshwater than any other human activity, and about one-third of that water is for livestock production.

Private residential water use makes up 5% of total consumption in the U.S. In contrast, animal agriculture makes up 55% of total water consumption. In the time it takes to brush your teeth, U.S. animal agriculture uses more than 209 million gallons of water.

  • Drinking water for farm animals accounted for water withdrawals of 2 billion gallons per day, mostly from fresh, groundwater sources, and are the equivalent to the amount of water consumed by 20,000 households over the course of an entire year. 

While animals do drink a lot of water, in the U.S., up to 98% of the water involved in livestock production was used to grow animal feed.

Factory Farms Contaminate Our Air

Raising animals in crowded conditions indoors surrounded by their own waste affects air quality inside the facilities, leading to high concentrations of ammonia, hydrogen sulfide, carbon dioxide and particulate matter (small particles that can be inhaled). This in turn impacts animals’ welfare, causing issues like respiratory diseases in cattle raised in feedlots and ammonia-induced eye and skin problems in chickens. Airborne contaminants from manure and dust also pollute the air in surrounding communities, pushed out of the facilities by ventilation systems in CAFO buildings and vaporized after manure is applied to land as fertilizer.

A recent study showed that agriculture in the U.S. results in over 12,000 air quality-related deaths attributable to animal agriculture each year. Ammonia and particulate matter from factory farms can cause asthma, bronchitis and other breathing problems, and long-term exposure to these emissions increases the risk of dying of heart disease, cancer and stroke. In addition to inhaling toxins, communities near CAFOs are plagued by noxious smells from manure lagoons, decreasing quality of life and home/property values, and causing serious mental health issues, including depression and anxiety.

Factory Farming Is Driving Climate Change

While the transportation and energy sectors are often called out for their role in climate change, it’s less understood that animal agriculture is responsible for 14.5% of all human-made greenhouse gases. Factory farms emit methane and nitrous oxide which are up to 300 times more damaging as greenhouse gases than carbon dioxide.

The greatest contributor to overall emissions from animal agriculture is the enormous production and processing of feed crops like corn and soybeans, which are the exclusive source of food for pigs and poultry species raised indoors on CAFOs and a significant portion of dairy and beef cows’ diet.  

Factory Farmed Animals Eat Environmentally Damaging Crops

Unlike animals raised on pasture who can graze—or in the case of pigs and birds, supplement their feed with forage and bugs—animals raised in confinement are restricted to grain-based feed for their entire lives. Nearly half of all corn and 70% percent of soy grown in the U.S. is produced to feed animals raised in CAFOs, and those crops rely on fossil fuels and use enormous quantities of chemical fertilizers and pesticides.

Soy production has been shown to cause waterway eutrophication (when water becomes uninhabitable due to excess nutrients) from fertilizer nutrient runoff and heavy herbicide application—herbicides were applied to 98% of planted soy acres in 2020. Most herbicides contain glyphosate, which may persist in soil, plants and water, reaching both surface water and groundwater—potentially changing the soil’s properties and growth and even causing human toxicity.

Similarly, corn fields growing for animal agriculture are heavily fertilized for maximum output. The excess nitrogen contributes to both waterway eutrophication and fine particulate matter air pollution.

Switch from Beef to Chicken? Not So Fast.

Some researchers have pointed out that beef production contributes the most to greenhouse gases and encourage consumers to “eat smaller” by consuming more poultry and fish. EPA data shows that beef and dairy production account for almost 80% of agriculture’s greenhouse gas emissions. But while poultry and some pork have lower production-related emissions, simply switching from beef to chicken is not a climate-friendly choice, and it does more harm to more animals. Alarmingly, it takes 134 chickens to get the same amount of meat as one cow, so as consumers swap beef for chicken, billions more animals suffer on factory farms.

Chicken CAFOs contribute heavily to air and water pollution and greenhouse gas emissions through feed production, fossil fuel use and manure management. One area where the pork, poultry and dairy industries’ environmental footprints equal or outweigh that of beef is in manure management, which represents a significant portion of livestock’s emissions. Poultry litter has been shown to contaminate surrounding waterways with excess nutrients such as nitrogen and phosphorous, causing dead zones and introducing pathogens including antibiotic-resistant bacteria. As this waste is applied to fields, the impact is felt in waterways. Poultry products also have a significant environmental footprint because of the reliance on pesticide- and herbicide-laden feed crops in a CAFO setting, as opposed to beef cattle and dairy cows, who sustain themselves on grass for at least part of their lives.

The Environmental Impacts of Plant-based Food

There is no question that industrial production of meat, eggs and dairy take a huge toll on animals, the environment and communities near these facilities. On top of subjecting animals to suffering and endangering our health, these industries require a staggering amount of our finite resources and produce climate-warming gases. Yet Americans are eating record amounts of animal products—an annual average of 138.4 pounds of red meat and poultry per person—the vast majority of which is from CAFOs. This is simply not sustainable. It is also not feasible or even environmentally beneficial to take all of the billions of animals currently housed in CAFOs and move them to pasture.

Meanwhile, resource use and greenhouse gas emissions from production of plant-based food is significantly lower than those from animal-based foods. Despite a few areas where plant-based products have a heavier water or land footprint, almost all of the leading ingredients in plant-based products consume significantly less land and water and have greatly reduced greenhouse gas emissions: 29% compared to 57% for conventional animal products.

Nearly one in four Americans (23%) said they were trying to eat less meat in 2019, and that number has continued to climb in later surveys.

Reducing animal products can range from cutting out meat for one or more days a week, going plant-based for breakfast and lunch, or opting for smaller portions of animal products. Increasing plants in one’s diet may mean swapping in some of the new products designed to mimic meat, eggs or dairy, or it may mean increasing beans, legumes, mushrooms and other hearty, nutrient-dense plant foods.

Plant-Based Impacts on Greenhouse Gas Emissions

Plant production doesn’t create emissions from animals’ digestion and manure, and eating crops is simply more efficient than eating an animal who consumed crops. For this reason, the United Nations’ IPCC Report on Climate Change identified that shifting diets from animal- to plant-based food has the power to help us fight climate change by drastically cutting our greenhouse gas emissions:

Carbon Footprint of Factory Farmed Animal Products

Plant-Based Impacts on Water Quality and Use

Most of the leading ingredients in plant-based alternatives[PDF] to beef, pork and chicken (wheat, soy, peas, mushrooms) use less water than their animal equivalents when factoring in both the water consumed by the animals and water used to grow the crops that feed them. Consumers can reduce animal product consumption by choosing alternative products with ingredients that have lower water usage.

Water usage of Factory Farmed Animal Products

Plant-based alternatives lack all of the water pollution caused by the accumulation of animals’ manure, but plant-based products aren’t perfect when it comes to water pollution from certain crops, like soy, which is both in animal feed and an ingredient in some plant-based meat and dairy alternatives. Soy may contribute to waterway eutrophication (when water becomes uninhabitable due to excess nutrients) from both fertilizer nutrient runoff and heavy herbicide application. Wheat—a key ingredient in many beef and chicken alternatives—also relies heavily on herbicides, with anywhere from 66% to 97% of planted acres treated in 2019. Herbicides used on wheat fields have been classified as “very toxic to aquatic life with long lasting effects.” Wheat also relies on heavy fertilizer use, risking excess nutrient runoff from applied fields into waterways, causing eutrophication. Canola oil, used in some dairy alternatives, commonly involves using the volatile organic compound solvent Hexane to extract the oil. Almonds often include the application of glyphosate. Even oats rely on two main herbicidal active ingredients, one of which includes glyphosate.

Plant-Based Impacts on Land

Half of the world’s habitable land is used for agriculture, most of which is used to raise farmed animals or feed them: animal agriculture accounts for 77% of global farming land. While livestock takes up most of the world’s agricultural land, it produces only 18% of the world’s calories and 37% of total protein, and the demand for land for animal agriculture is the leading driver of deforestation and biodiversity loss. Research suggests that if everyone shifted to a plant-based diet, we would reduce global land use for agriculture by 75%. This would benefit the planet and animals alike as habitats could be restored with carbon-capturing forests and meadows.

Land Usage of Factory Farmed Animals

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The Environmental Benefits of Pasture-Based Foods

Raising animals indoors in intensive confinement is extremely harmful to animals and our environment. Plant-based food can dramatically reduce those harms. But given that the majority of people will continue to eat meat, eggs or dairy, is there a form of animal agriculture that is better for animals and our environment?

Industry groups are focused on technologies and feed additives that marginally reduce greenhouse gas emissions, but this approach does not address the underlying cause of the pollution and environmental damage, not to mention intense animal suffering. Pasture-raising animals, on the other hand, addresses that imbalance: there are fewer animals, animals are raised outdoors at densities that meet the land’s carrying capacity, more manure is spread across the land and, in the case of grazing animals, there is less reliance on feed crops.

While raising animals on well-managed pastures can improve water quality and reduce water demand, improve soil health and even mitigate climate impacts, this land- and time-intensive approach to animal agriculture also has some real environmental limits. To achieve the joint animal and environmental benefits of pasture-based farming, we must raise significantly fewer animals annually, which means reducing consumption of animal products.

Pasture-Based Impacts on Water Use and Quality 

Because manure on pasture-based farms is generally not stored in lagoons or pits, pasture-based systems have greatly reduced risks of water impairment events since they don’t run the risk of manure leaching into groundwater or runoff into local waterways.

Farm animals in CAFOs require significant amounts of water both for drinking and as an input for the massive amounts of grain required for feed. When ruminant animals (beef cattle, dairy cows, sheep, goats) are pasture-raised, they rely on grasses that are predominantly rain-fed and store moisture in the soil, thus reducing water usage in the system. While CAFOs and grain production deplete water reserves, pastures that include a diverse mixture of grasses, legumes and broadleaf plants, including drought-resistant species, can often withstand water shortages

Further benefits to water are gained through pasture-based farming’s reduced reliance on feed crops. Corn and soy are water-intensive products which, when grown for conventional feed crops, tend to pollute waterways. Soy production has been shown to cause waterway eutrophication (when water becomes uninhabitable due to excess nutrients) from fertilizer nutrient runoff and heavy herbicide application. Most of the herbicides contain glyphosate —which may persist in soil, plants and water, reaching both surface water and groundwater,—potentially changing the soil’s properties and growth, and even causing human toxicity

Similarly, corn grown for animal agriculture is heavily fertilized for maximum output and the excess nitrogen contributes to waterway eutrophication. Alfalfa also commonly relies on herbicides and pesticides.

Pasture-Based Impacts on Soil Health

Grazing animals distribute manure in sustainable amounts directly on the land, building soil health and recycling nutrients. The U.S. is losing an unsustainable amount of nutrient-rich topsoil each year, in large part because of practices used to grow corn and soy for animal feed. Well-managed grazing returns nutrients to the soil—moderate amounts of manure act as natural fertilizers for the soil. Compared with row crops, pasture-raising animals reduces soil loss by as much as 93%. Integrating livestock into crop rotations can control weeds, increase yields and reduce fertilizer use.

Pasture-Based Impacts on Greenhouse Gas Emissions

Manure distributed by animals on pasture emits fewer toxins and greenhouse gases than lagoon or pit manure storage associated with factory farming. One study showed that shifting pigs to pasture-based systems could realize a 29% reduction in nitrous oxide emissions and a 7% reduction in methane emissions when compared to the emissions of an industrial factory farm.

For pasture-based systems to have a relatively beneficial impact on greenhouse gas emissions, the animals’ movement and the pasture itself needs to be closely managed. A study showed that farm animal management systems such as “adaptive multi-paddock grazing” have the potential to cut livestock emissions by more than half when compared to intensive CAFO systems.

Well-managed grazing -- where animals are moved regularly to allow the pasture to rejuvenate and pastures are seeded with high quality forage that accelerates animals’ growth -- can help restore degraded rangeland and increase soil carbon sequestration (the re-capture of carbon) through plant growth and improved soil health. The Food & Agriculture Organization estimated that improved grazing management practices on current grasslands had the combined potential to trap the equivalent of 585 million tons of carbon over 20 years, representing about 8% of livestock supply chain emissions. With reduced demand for factory farmed animal products, the conversion of land currently used to grow conventional feed crops into well-managed pastureland could further offset the greenhouse gas emissions of animal agriculture.

While conversion of land used for feed crops to pasture could have benefits to the environment, other types of land conversion to expand pasture-based farming, such as converting forest to pasture, has the opposite effect and instead leads to an increased carbon footprint.

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Take Action: How You Can Protect Animals & The Environment

Researchers, farmers and advocates continue to debate the comparative environmental and animal benefits of eating plant-based foods versus more humane, pasture-based animal products. The truth is, either or any combination of these two approaches can spare farmed animals from the suffering they endure now on factory farms and reduce our individual dietary impact on the environment. What matters most is that we take some action. It’s not all or nothing, but for animals and the environment it’s urgent that we each do something. 

Two actions you can take today to move our food system away from factory farming and toward more plant- and pasture-based foods:

  1. Support the Farm System Reform Act a federal bill that would phase out factory farming and provide funds for those farmers to transition to crop production or raising animals on pasture.
  2. Try the Factory Farm Detox to learn how to shop for more plant-based and welfare-certified, pasture-raised animal products. Sign up to receive a free list of more-humane products and farms and other helpful resources.