Environmental impact of meat production

The environmental impact of meat production varies based on the wide variety of agricultural practices employed around the world. All agriculture practices have been found to have a variety of effects on the environment. Some of the environmental effects that have been associated with meat production are pollution,fossil fuels , water, and land consumption. Meat is cultivated through a variety of methods:

• Organic farming
• Free range farming
• Factory farms
• Subsistence agriculture
• Hunting
• Fishing

According to a 2006 report by the Livestock, Environment And Development Initiative, the livestock industry is one of the largest contributors to environmental degradation worldwide, and modern practices of raising animals for food contribute on a "massive scale" to air and water pollution, land degradation, climate change, and loss of biodiversity. The initiative concluded that "the livestock sector emerges as one of the top two or three most significant contributors to the most serious environmental problems, at every scale from local to global." In 2006 the Food and Agriculture Organization estimated that meat industry contributes 18% of all emissions of greenhouse gasses. This figure was challenged in 2009 by two World-Watch researchers who estimated a 51% minimum, however this paper has not been peer reviewed.

Animals fed on grain need more water than grain crops. In tracking food animal production from the feed through to the dinner table, the inefficiencies of meat, milk and egg production range from a 4:1 energy input to protein output ratio up to 54:1. The result is that producing animal-based food is typically much less efficient than the harvesting of grains, vegetables, legumes, seeds and fruits for direct human consumption.

Grazing and land use

Dryland grazing on the Great Plains in Colorado

Although it requires less land for the livestock, factory farming requires large quantities of feed. The growing of cereals for feed in turn requires substantial areas of land. Free-range animal production requires land for grazing, which has led to encroachment on undeveloped lands as well as clear cutting of forests. Such expansion has increased the rate of species extinction and damaged certain abilities of nature, such as the natural processing of pollutants.

According to the United Nations, "Ranching-induced deforestation is one of the main causes of loss of some unique plant and animal species in the tropical rainforests of Central and South America as well as carbon release in the atmosphere." The Food and Agriculture Organization (FAO) agrees, saying that "Expanding livestock production is one of the main drivers of the destruction of tropical rain forests in Latin America, which is causing serious environmental degradation in the region." An earlier FAO study found that 90% of deforestation is caused by unsustainable agricultural practices. Logging and plantation forestry, though not as major contributors to deforestation, play a greater role in forest degradation.

Raising animals for human consumption accounts for approximately 40% of the total amount of agricultural output in industrialized countries today and livestock is the world’s largest land user. Grazing occupies 26% of the Earth’s surface, and feed crop production uses about one third of all arable land.

Because of this enormous requirement for land use, land degradation such as deforestation, desertification, and soil quality decline, which are already major global problems, are becoming more significant. Grazing land expansion for livestock is a major factor in deforestation, especially in Latin America. Approximately 70% of previously forested land in the Amazon is now used as pasture, while feed crops cover a large part of the remaining 30%. As much as 70% of grazing land is considered degraded due to overgrazing, compaction and erosion related to livestock activity. Extended heavy grazing also contributes to the disappearance of edible plant species, and the successive overgrowth of other inedible plants and bushes.

Overgrazing is also associated with both soil quality decline and deforestation as farmers and ranchers encroach on forested areas in search of plots of land on which to feed their animals. In the United States, 60-68 percent of the federal grazing land maintained by the US Bureau of Land Management (170 million acres) is classified in poor or fair condition. With very few plants, fertile topsoil is swept away by erosive forces such as wind or water. Deforestation has also been a significant problem in many areas, including Latin America, where 20 million hectares of tropical forest were cleared for cattle between 1970 and 1994.

Water resources

Estimated virtual water requirements
for various crops (m³ water/ton crop)

	Hoekstra & Hung (2003)	Chapagain & Hoekstra (2003)	Zimmer & Renault (2003)	Oki et al. (2003)	Average
Beef		15977	13500	20700	16726
Pork		5906	4600	5900	5469
Cheese		5288			5288
Poultry		2828	4100	4500	3809
Eggs		4657	2700	3200	3519
Rice	2656		1400	3600	2552
Soybeans	2300		2750	2500	2517
Wheat	1150		1160	2000	1437
Maize	450		710	1900	1020
Milk		865	790	560	738
Potatoes	160		105		133

See also: Water conservation

Producing a certain quantity of food in meat requires much more water than producing the same amount of food in grain.

According to the vegetarian author John Robbins, it roughly takes 60, 108, 168, and 229 pounds of water to produce a pound of potatoes, wheat, corn and rice respectively. He reports that a pound of beef however, requires 12,000 gallons of water.

David Pimentel explained of his calculations that:

The data we had indicated that a beef animal consumed 100 kg of hay and 4 kg of grain per 1 kg of beef produced. Using the basic rule that it takes about 1,000 liters of water to produce 1 kg of hay and grain, thus about 100,000 liters were required to produce the 1 kg of beef.

Effects on aquatic ecosystems

Significant negative effects of aquatic and riparian ecosystems are also associated with meat production in the United States; In the Western United States 80% of stream and riparian habitats have been negatively impacted by livestock grazing. This has resulted in increased phosphates, nitrates, decreased dissolved oxygen, increased temperature, turbidity, and eutrophication events, and reduced species diversity (Belsky et al., 1999). In the Eastern United States waste release from pork farms have also been shown to cause large-scale eutrophication of bodies of water, including the Mississippi River and Atlantic Ocean (Palmquist, et al., 1997).

Fossil fuel consumption and greenhouse gas emissions

Farmer ploughing rice paddy, in Indonesia. Animals can provide a useful source of draught power to farmers in the developing world

At a global scale, a 29 November 2006 United Nations report called the Livestock's Long Shadow - Environmental Issues and Options assesses the meat and livestock industry to contribute to about 9% of total anthropogenic carbon dioxide emissions, including 37% of methane and 65% of nitrous oxide emissions.

At a local level, livestock represents up to half of New Zealand's greenhouse gas emissions, and nearly 20% of the total methane emissions of the United States of America. Not all forms of meat and animal–based foods impact the environment equally. According to one research group, those with the greatest impact include lamb (#1), beef (#2), cheese (#3), and pork (#4). Red meats in particular are 150% more greenhouse gas intensive than chicken or fish.

Indirect effects account for most of agricultural greenhouse gas emissions, and are attributed to emissions of nitrous oxides and other gases from concentrated livestock operations and from microbial activities in soil and water following applications of fertilizers . Greenhouse gas emissions are not limited to animal husbandry; for instance, in many countries where rice is the main cereal crop, rice cultivation is responsible for most of the methane emissions.

The production of protein from grain-fed animals requires eight times as much fossil-fuel energy as the production of plant protein. According to an article in Environmental Health Perspectives, typical feedlot husbandry of cattle requires an input of 35 kcal of fossil fuel to produce one kcal of food energy in beef, far more than that required for comparable plants.

A 2006 study at the University of Chicago concluded that a person switching from a typical American diet to eating 20% less meat, or about 6 oz a day would prevent the emission of 1485 kg of carbon dioxide. The difference exceeds that of an individual switching from a Toyota Camry to the hybrid Toyota Prius, and collectively amounts to over 6% of the total U.S. greenhouse gas emissions.

This view, however, reflects the situation in the developed world and does not take into account the situation in most third world countries. In the developing world, notably Asia and Africa, fossil fuels are seldom used to transport feed for farm animals. Sheep or goats, for example, require no fuel, since they graze on farmlands, while bales of hay for bovines are still transported mainly using bullock carts or similar devices. Little to no meat processing takes place in the vast majority of the developing world. Animals are also often herded to the place of slaughter (with the exception of poultry) resulting in a very low use of fossil fuels. In fact, farm animals in the developing world are used for multiple purposes, from providing draught power to transportation, while also serving as meat once they reach the end of their economic lives.

A more efficient use of animal waste may be a contributing factor in sustainability. The by-products of slaughtered animals can be used to provide biogas. Trains running on this fuel are already in operation in Sweden. The use of biogas to run mass transit is likely only possible as a side effect of industrial agriculture.

The UN has admitted a report linking livestock to global warming exaggerated the impact of eating meat on climate change. Dr Frank Mitloehner, from the University of California at Davis (UCD), said meat and milk production generates less greenhouse gas than most environmentalists claim and that the emissions figures were calculated differently to the transport figures, resulting in an “apples-and-oranges analogy that truly confused the issue”. The meat figure had been reached by adding all greenhouse-gas emissions associated with meat production, including fertilizer production, land clearance, methane emissions and vehicle use on farms, whereas the transport figure had only included the burning of fossil fuels. In the original press release in which Dr. Mitloehner's assertions appear, it transpires that his work was funded by a $26,000 grant from the Beef Checkoff Program. In addition, his comments do not state that the UN's calculations are false, but rather that they considered the entire commodity chain, which they did not do for transport.

See also

• Environmental impact of agriculture
• Agroecology
• Sustainable agriculture
• Environmental vegetarianism

Further reading

• McMichael AJ, Powles JW, Butler CD, Uauy R (2007 Sep 12). "Food, livestock production, energy, climate change, and health". Lancet 370 (9594): 1253. doi:10.1016/S0140-6736(07)61256-2. PMID 17868818. http://www.eurekalert.org/images/release_graphics/pdf/EH5.pdf. 
• Baroni L, Cenci L, Tettamanti M, Berati M. (2007 Feb). "Evaluating the environmental impact of various dietary patterns combined with different food production systems". Eur J Clin Nutr. 61 (2): 279–86. doi:10.1038/sj.ejcn.1602522. PMID 17035955. http://www-personal.umich.edu/~choucc/environmental_impact_of_various_dietary_patterns.pdf. 
• Heitschmidt RK, Vermeire LT, Grings EE. (2004). "Is rangeland agriculture sustainable?". J Anim Sci. 82 (E-Suppl): E138–146. PMID 15471792.