The Hidden Externalities Behind Animal Agriculture

By Nicole Behler

Animal agriculture is a seemingly ordinary industry to the every day American. When we see meat or dairy in the store, most people don’t think about the economics behind a carton of milk or a T-bone steak. The reality is that the production of meat and dairy causes many negative externalities to the environment and human health, and is one of the leading causes of climate change. Animal agriculture impacts the planet in a variety of ways including increasing greenhouse gas emissions, causing deforestation, and creating toxic waste runoff.

The first negative externality and one that many people may laugh at, is that animal agriculture accounts for about 18 percent of greenhouse gas emissions (Livestock’s…). According to Independent, “Robert Goodland, a former lead environmental adviser to the World Bank, and Jeff Anhang, a current adviser, suggest that domesticated animals cause 32 billion tons of carbon dioxide equivalent (CO2e), more than the combined impact of industry and energy” (Correspondent). The article then articulates the fact that livestock emits about 37 percent of the world’s methane. A high human population means the demand for more and more livestock to feed our populations resulting in higher greenhouse gas emissions. According to Goodland and Anhang, “A key risk factor for climate change is the growth of the human population, projected to be roughly 35 percent between 2006 and 2050.In the same period, the FAO projects that the number of livestock worldwide will double, so livestock-related GHG emissions would also approximately double” (15).

The second negative externality that I want to touch on is land use. The use of land for animal agricultures causes another string of negative externalities on its own. In order to raise cattle, the animals need pastures to graze on; because of the growing human population and resulting growing number of cattle being raised to feed our population, more and more land is being cleared in order for this industry to grow. Clearing land for agricultural use causes deforestation, habitat destruction, species extinction, and pollution of waterways. Deforestation of the Amazon Rainforest has become one of the main points of focus for environmentalists. “Until 1970 the deforested areas used for agriculture and cattle ranching in Amazonia accounted for less than 3 percent of the total area of the region. Today, such areas account for over 10 percent” (Margulis, 9). Habitat destruction is considered one of the biggest causes of biodiversity loss. When forests are cleared, animals are either killed or forced to migrate to neighboring areas; this is called habitat fragmenting. Habitat fragmenting is harmful for a number of reasons; it causes populations to split off into smaller groups making it harder for them to repopulate, increasing crowding, and decreasing food availability. The increasing friction between native animal populations and humans developing land increases loss of biodiversity in places like the Amazon.


Lastly, toxic waste runoff is another huge negative externality that animal agriculture causes. The runoff produced by the waste of cattle causes ocean dead zones when not disposed of properly. Many factory farms do not dispose of their waste properly because of the cost of waste water treatment. Ocean dead zones are basically parts of the ocean that cannot support life because of the lack of oxygen in the water. According to Scientific American:

“Dead zones occur around the world, but primarily near areas where heavy agricultural and industrial activity spill nutrients into the water and compromise its quality accordingly. Some dead zones do occur naturally, but the prevalence of them since the 1970s—when dead zones were detected in Chesapeake Bay off Maryland as well as in Scandinavia’s Kattegat Strait, the mouth of the Baltic Sea, the Black Sea and the northern Adriatic—hints at mankind’s impact.”

ocean dead zones

Overall, this is a hard subject to talk about because everything involved is connected in some way and an impact on one part of the environment causes a chain reaction to other parts. As much as I wish I could keep writing  further about each area mentioned above, I will leave it at this and hopefully learning a few facts about the hidden externalities behind the animal agriculture industry will make you think twice about the products you consume and the industries you choose to support.

Work Cited

Correspondent, Martin Hickman Consumer Affairs. “Study claims meat creates half of all greenhouse gases.” The Independent, Independent Digital News and Media, 31 Oct. 2009,

Goodland, Robert & Anhang, Jeff. “Livestock and Climate Change: What if the key actors in climate change are…cows, pigs and chickens?”. WorldWatch. November/December 2009

“Livestock’s Long Shadow: environmental issues and options”. Food and Agriculture Organization of the United Nations. Rome 2006

Margulis, Sergio. Causes of deforestation of the Brazilian Amazon. The World Bank, 2004.

Pesticides in the Nation’s Streams and Ground Water, 1992–2001—A Summary, Mar. 2006,

“What Causes Ocean “Dead Zones”?” Scientific American,


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