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Jocelyn Hsu / Spoon

The Devastating Environmental Impact of CAFOs

This article is written by a student writer from the Her Campus at Simmons chapter.

If you eat animal products, there is a good chance that they come from a CAFO or “concentrated animal feeding operation”. The U.S Department of Agriculture defines a CAFO as an “intensive animal feeding operation in which 1000 animal units are confined for over 45 days a year.” Because CAFOs produce so many animal products (about 99% of animal products in the United States), they require a significant amount of land, water, and energy to sustain them. CAFOs are a leading source of air and water pollution and contribute to antibiotic resistance and the spread of zoonotic diseases. Here’s how: 


Water Usage 

Freshwater is a limited resource on earth- only 2.5% of earth’s water is fresh. Of that 2%, most of it (about 69%) is trapped in ice and glaciers and is therefore inaccessible. The remainder of that water is found belowground (30.1%) in water bodies (0.47%) and the atmosphere (1.2%). 

With the increasing frequency of drought accelerated by climate change, it is now more important than ever to conserve water. Because of the large number of animals confined in them, CAFOs are one of the biggest consumers and polluters of freshwater in the United States.  

To calculate the volume of water required to raise animals, you must remember to take into account the water used to irrigate the crops grown for animal feed. It takes about 1,800 gallons of water to produce one pound of beef. For reference, just 34 gallons are needed to grow a pound of potatoes, 50 gallons for a pound of apples, and 26 for a pound of tomatoes. 

To view the water footprint of other foods, visit the Water Footprint Network. 


Methane Emissions 

Methane is a greenhouse gas, meaning it traps heat in the atmosphere and causes the earth’s average temperature to rise. It is about 24 times better at trapping heat in the atmosphere than carbon dioxide and accounts for 10% of greenhouse gas emissions in the United States. Enteric fermentation, a digestive process in ruminant animals (such as cows, sheep, and goats), produces methane as a by-product and accounts for 28% of methane emissions in the United States. Manure management accounts for another 10%. 

Modifications to animal feed and manure management could potentially reduce emissions, but decreasing the number of farm animals is the most effective method. 



Pollution, not to be confused with greenhouse gases, specifically refers to any substance introduced to the environment that has harmful or poisonous effects.  

Most pollution from CAFOs stems from the vast amounts of animal waste. CAFOs store animal waste in large pools called lagoons, which contain feces from livestock as well as heavy metals, antibiotics, blood, and growth hormones. Open lagoons emit toxic gases such as ammonia and hydrogen sulfide (as well as greenhouse gases like nitrous oxide and methane). 

Agricultural workers often empty lagoons by liquifying the waste and spraying it onto neighboring fields, where plants cannot absorb the high concentration of nutrients. When it rains, the waste runs off into nearby bodies of water, creating algae blooms and turning the environment eutrophic and under oxygenated. 

Another problem with animal agricultural runoff is the presence of E.coli bacteria, commonly found in the intestines and feces of animals. Most strains are harmless, but humans can contract severe intestinal infections through consuming water or undercooked beef contaminated with E.coli.

U.S industrial farms produce 20 times more fecal waste than the entire U.S population each year- about 1.37 billion tonnes. Livestock waste is more concentrated (up to 100 times) than human waste and does not have to be treated by a wastewater plant before being released back into waterways. 


Zoonotic Disease & Deforestation

A Zoonotic disease, such as rabies, spreads between different animal species. Infectious disease experts estimate that 3 out of every 4 new or emerging infectious diseases originate in animals. 

Animals living in crowded, unsanitary, and stressful environments have an increased likelihood of contracting an illness. A report titled Zoonotic Diseases, Human Health, and Farm Animal Welfare, found that rises in meat consumption increase the risk of exposure to harmful foodborne pathogens. The report also found that new strains of the influenza virus may be emerging as a result of the long-distance transportation of animals. 

Deforestation and habitat destruction can also increase the likelihood of a wild animal passing a pathogen to a human. When habitats remain in their natural state, undisturbed by humans, most viruses circulate in mild forms among the populations. However, when humans disrupt the environment through actions such as logging, mining, or oil exploitation, they risk coming into contact with these viruses that would otherwise not affect them.

Without a place to live, wild animals will often migrate closer to humans, again increasing the likelihood of pathogen exposure. Habitat loss affects biodiversity, resilience to natural disasters, and climate change. Animal Agriculture is responsible for about 80% of Amazon rainforest destruction and uses up 60% of Earth’s arable land, which is a limited resource on Earth. A study conducted by The Animals calculated that producing just one-quarter pound of beef requires 65 square feet of land for its feed alone. 

The land used to grow feed for livestock could otherwise be used to grow crops for humans or be left alone to turn back into natural habitats to sustain more biodiverse ecosystems. 


Antibiotic Resistance 

Antibiotic resistant bacteria have been on the rise in recent years and recognized as a top public safety threat by the CDC. When antibiotics are overused, the bacteria they target are more likely to develop genetic mutations to survive and pass them onto their offspring, eventually creating a whole population of resistant bacteria and making the antibiotic useless. 

While doctors often overprescribe antibiotics to their patients, most (about 80%) antibiotics in the United States are given to farm animals by agricultural workers. This overprescription is not because farm animals routinely fall ill, but to prevent illness and promote growth. Antibiotic-resistant bacteria can spread to humans through manure, meat, and water contamination. The CDC estimates that 2.6 million people in the United States suffer from antibiotic infections each year and that 20% of those are related to the consumption of food containing antibiotic-resistant bacteria. 

We must transform our food systems into more sustainable operations and rethink our relationship with animals and our planet if we want to preserve the natural resources they have to offer. 

If you are concerned about the environmental impacts of CAFOs, consider sourcing your animal products from smaller farms or reducing your intake altogether. 

My name is Bella and I'm an environmental science major! I love writing about sustainability and I'm currently working on recording an original song!