Ecological Effects of a Meat-Based Diet

Why a Global Change to Vegetarianism will Save the Planet

Katharyn Jeffreys

12-3-98

1.80

 

 

 

 

 

 

Isn't man an amazing Animal?  He kills wildlife--birds, kangaroos, deer, all kinds of cats, coyotes, beavers, groundhogs, mice, foxes, and dingoes--by the million in order to protect his domestic animals and their feed.

 

Then he kills domestic animals by the billion and eats them.  This in turn kills man by the million, because eating all those animals leads to degenerative--and fatal--health conditions like heart disease, kidney disease, and cancer.

 

So then man tortures and kills millions more animals to look for cures for these diseases.

 

Elsewhere, millions of other human beings are being killed by hunger and malnutrition because food they could eat is being used to fatten domestic animals.

 

Meanwhile, some people are dying of sad laughter at the absurdity of man, who kills so easily and so violently, and once a year sends out cards praying for ‘Peace on Earth.’

 

From “Old MacDonald's Factory Farm,” by C. David Coats
Introduction

 

FIGURE 1: World Meat Production 1950-1989.

Source: Modified from Durning 1991.

Raising animals for human consumption has many effects that are of ecological concern.  By examining the magnitude of damage caused by livestock production, the effects of worldwide vegetarianism can be estimated.  The production of meat is increasing (Figure 1), and with it comes many environmental hazards.  Methane (CH4) from livestock manure and flatulence increases global warming.  Water is polluted by runoff from animal wastes and freshwater sources are depleted for feed irrigation and consumption by livestock.  The soil is affected by desertification and erosion.  The direct and indirect effects of both deforestation and the use of land to grow livestock feed are felt in all ecosystems.  These issues all lead to questions of sustainability and maintained biodiversity on Earth.

In examining the hypothetical situation of a world of human vegetarians, a few assumptions must be made.  This primarily refers to the definition of vegetarian.  For most purposes, a vegetarian is a person who does not consume any meat.  For the purpose of this study, meat is defined as beef, poultry, pork and fish.  A vegetarian (or ovo-lacto vegetarian) does consume eggs and dairy products. 

The term vegan generally refers to a person who consumes no milk products or eggs, but true vegans also eliminate all other animal derived products, including oils from fish, dyes from insects, and cloth from animal skins.  It is nearly impossible to estimate the effects of worldwide veganism, or the absence of any animal by-product in the diet, because animal byproducts are present in small amounts in a myriad products.  It is difficult to quantify the amount of resources used in these applications, as many are obscure and are not sufficiently monitored.  However, because much agricultural data includes dairy cattle and egg producing chickens as livestock, these animal products will be included in the list of foods not consumed by a vegetarian. 

Therefore, to determine the ecological changes that would occur if every human were vegetarian, an analysis will be made under the assumption that global vegetarianism means no livestock are raised to be slaughtered, fishing is eliminated, and agricultural milk and egg production ceases.  This definition encompasses most of the uses of animals that influence our environment and allows for a reasonable estimation of the magnitude of the impact of livestock.

 

Nutrition as a measure and justification

The basis for comparing vegetarian and meat consuming diets must be done in nutritional terms.  It is important to be reassured that a vegetarian diet is indeed a nutritionally feasible alternative.  When examining the resources used to feed people, including crops and land, units of pounds or acres are often used.  These terms are abstract when trying to indicate how many people are fed using the earth’s resources.  Therefore, when studying the effects of global vegetarianism, it is necessary to use the amount of natural resources required to produce a nutritionally balanced diet.  Consequently, any data that provides a  purely quantitative comparison will be adjusted to provide a nutritional comparison.  Based on the food pyramid (Figure 2) established by the United States Department of Agriculture (USDA), the only aspects of a vegetarian diet that require examination are the consumption of proteins and milk products.

FIGURE 2: United States Department of Agriculture’s Food Guide Pyramid.

Source: USDA 1998.

 

Protein is an essential part of the human diet and is most frequently associated with meat products.  The USDA (1998) defines a serving of meat-based protein as two to three ounces of cooked lean meat, poultry, or fish.  The American Dietetic Association’s Food Guide Pyramid for Vegetarian Meal Planning (1998) outlines one serving of protein as 1 cup soy milk, ½ cup cooked dry beans or peas, 2 tablespoons nuts or seeds, ¼ cup tofu or tempeh, or 2 tablespoons peanut butter.  Therefore it can be assumed that the recommended daily consumption of protein could shift from 6 ounces of meat to 1.5 cups of dry beans.  This seemingly large quantity of food would not be consumed simply as beans, but serves as a representation of the many protein rich byproducts available, including peanut butter, tofu, and “veggie burgers.”  Whatever the form, protein will be represented by 1.5 cups of dry beans, weighing approximately 300 grams, thus allowing for comparisons to the livestock industry to be made. 

Because of the assumed elimination of dairy products from the diet, other sources of calcium must be found.  These can include beverages fortified with calcium, such as orange juice or soy milk.  Additionally, many legumes and green leafy vegetables are good sources of calcium.  According to the Physicians’ Committee for Responsible Medicine (1998), “diets that are high in protein cause more calcium to be lost through the urine. Protein from animal products is much more likely to cause calcium loss than protein from plant foods.” Therefore, calcium consumed by vegetarians is more efficiently absorbed into the body.  Because calcium can be found in non-animal sources, this nutrient can be disregarded when considering any nutritional importance of dairy products.

There are many other nutrients that are found naturally in meat products (some exclusively) that must be accounted for, such as Vitamins D and B-12, Iron, and Zinc.  The American Dietetic Association (1998) makes many recommendations on vegetarian or synthetic sources of these nutrients.  Vitamin D can be obtained naturally through sun exposure to the hands, arms and face for five to fifteen minutes per day. Vitamin B-12, only required in small amounts, can be found in many fortified cereals and in dietary supplements.  Zinc and Iron are both found in grains, soyfoods, and legumes.  Other necessary vitamins such as E, K, B2, B6, and A, which are present in animal proteins, can also be found in vegetables such as spinach, broccoli, asparagus, or carrots (Mindel 1998).

All the vitamins, minerals, and nutrients needed by humans can be found in ample amounts in vegetable sources.  In fact, the elimination of animal products from the diet reduces the probability of the occurrence of many health problems, including cancers and heart diseases.  Having established the feasibility and equivalence of a vegetarian diet, it is now possible to evaluate the impact of meat consumption on the environment. 

 

Water

 

Water is the most precious natural resource the earth offers, and it is threatened in many ways by raising domestic animals for food.  Fresh water is consumed by livestock and used to irrigate feed crops.  Additionally, groundwater, lakes, and oceans are contaminated by wastes from farm animals.  According to the Vegetarian Society, Inc. (1998), 40 percent of the nitrogen and 35 percent of the phosphorus released into U.S. freshwater sources come from animal excrement and fertilizers.  This mistreatment of our water results in poor drinking water supplies as well as disruption of natural aquatic ecosystems.

The amount of water used to raise a steer is staggering: enough to float a destroyer (Teisler-Rice 1996).  A cow raised for slaughtered can consume up to nine gallons of water in a single day, and an additional 800 gallons of water are used to process a single cow carcass once it is slaughtered (Harris 1996).  Harris also states that “nearly 2,500 gallons of water are required to produce a solitary pound of beef, a life cycle analysis that factors in water for irrigating feed crops, drinking, processing and handling.”  The amount of water needed to produce an equivalent amount of chicken (based on protein content) is one fourth the amount needed for beef.  According to the USDA’s Nutrient Data Laboratory, tofu has half the amount of protein per weight of chicken and beef.  Nonetheless, the quantity of water used to produce a certain amount of protein in beef is 5 times that required for an equal amount of protein in tofu. 

While some may claim, as does the National Cattlemen's Beef Association (1998), that water used in livestock production is not “used up” because it is naturally recycled through  the hydrological cycle, this is not the case.  It is impossible to replace the uncontaminated fresh water removed from underground aquifers that accumulated there over half a million years (Marcus 1998).

Using marine animals as a commercial food source is also harmful to aquatic ecosystems.  Teisler-Rice (1998) cites an example of the drastic population decrease in oyster beds in the Chesapeake Bay due to human harvesting of oysters.  These mollusks are natural filters, and it now takes a year for them to filter all the water in the bay.  However, one hundred years ago, when their population was unaffected by humans, it would have taken only a week.  Because not much is known about the long term global importance of the sea ecosystem, it is hard to judge the impact of this massive global reduction of the fish and mollusk population. 

Aside from physical destruction of aquatic ecosystems, biodiversity in lakes and oceans is also threatened by the fishing industry.  The World Conservation Union listed over 100 species of fish as threatened or endangered in 1996.  Commercial fishing is driving once-common types of fish such as halibut and cod to near extinction (Teisler-Rice 1998).  Because these fish are endangered and therefore protected under federal guidelines, it has become necessary to find other species of fish for commercial consumption. As a result, humans are now eating fish from lower on the food chain.  While this is admirable from an energy transfer standpoint, it also means that the food of the endangered fish is being consumed by humans.

            An additional threat to our water supply is the irresponsible disposal of the millions of tons of solid manure produced by livestock each year (Table 1).  Five tons of animal manure are produced for each person in the United States.  This is an enormous amount of waste when compared to the 80 pounds of solid waste produced by each human (Harkin 1997).  As the number of farms decreases and farm size grows accordingly, the concentration of these wastes in certain areas increases.  Some farms output more waste that a city as large as Los Angeles, as is the case with one 50,000 acre hog farm in southwest Utah (Harkin 1997).

 

Kg/ton manure

Animal

N

P

Dairy Cattle

5.6

1.0

Finishing Cattle

7.0

2.0

Hogs

5.0

1.4

Horses

6.9

1.0

Sheep

14.0

2.1

 

TABLE 1: Characteristics of various animal manures

Source: Modified from Cox 1979.

Some manure can be used to fertilize other crops, because of its high mineral content.  However, when there is a large amount of waste produced in one area, there is not enough local crop land on which to apply the manure.  Additionally, there is a physiological capacity of existing crop varieties to use fertilizer. Once this threshold of useable nutrients is reached, crop returns diminish (Brown 1996).  Furthermore, since the nutrients cannot be used by the surface plants, the fertilizer makes it way into the groundwater where it contaminates the water, such that it is safe for neither humans nor wildlife.

The leaching of nutrients into water supplies results in excessive growth and decay of algae.  This results in the depletion of dissolved oxygen, or hypoxia.  In the Gulf of Mexico, the algae in the nutrient enriched waters have created a 7,000 square mile “dead zone” that can no longer support life (Harkin 1997).  This effect, as well as numerous fish kills from contaminated water around the globe, is as much a threat to our aquatic ecosystem as commercial fishing.

Nutrients from rotting carcasses can also affect an aquatic ecosystem on more local scale.  Cattle ranges occupy terrain that often includes waterways.  Marcus (1998) states that is not uncommon for cattle to die in these streams and rivers, where they remain to decay, releasing nutrients.  These nutrients travel downstream and influence habitats outside the rangeland.

Water is a natural resource that is required for life.  By contaminating it, using it to raise livestock, and destroying the ecosystems within it, the availability of fresh water for future generations in endangered.

 

Soil

 

            Topsoil erosion and desertification threaten sustainability around the globe In fact 35 pounds of topsoil are eroded for each pound of feedlot beef produced (Teisler-Rice 1996).  As the soil erodes, the land cannot produce crops as efficiently (Brown 1996). Teisler-Rice (1998) states that approximately 54 percent of U.S. pasture land is overgrazed and experiences wind and water erosion.  Additionally, about 90 percent of U.S. cropland is eroding at 13 times the sustainable rate.

            Desertification is another problem associated with rangeland livestock.  Durning (1991) provides a common example of how this destruction of the land occurs.  The cattle overgraze the grasses, which are replaced by weeds and shrubs that have less tenacious roots, allowing them to be trampled.  As the soil is packed down, rain can not penetrate, so it runs off, carrying the nutrient-rich topsoil with it.  Conversely, if water is not abundant, the soil, unprotected by grasses, blows away in the wind. 

A thick nutrient-rich layer of soil is necessary for growing crops, and even the most valiant attempt at fertilization would fall short of replicating the quality of the original soil. Additionally, this artificial replacement of nutrients has a negative impact on the quality and biodiversity of water systems.

 

Air

 

The maltreatment of our land and water have important effects on the atmosphere. A detailed study conducted by the United States Department of Agriculture and the Environmental Protection Agency which determined that ground-level ozone and other forms of air pollution are reducing U.S. crop production by 5 to 10 percent (Brown 1996).  This pollution has many causes, including methane released from animal wastes and the global reduction of conversion of carbon dioxide to oxygen due to deforestation. 

As greenhouse gases (including methane and carbon dioxide) increase in the atmosphere, the temperature around the globe swells.  The past two decades have included the 11 warmest years since recording began in 1866.  The heat affects crop production, especially that of grains.  In 1988, high temperatures and drought caused grain production to fall below consumption levels for the first time in the history of the United States (Brown 1996).  Methane is released into the atmosphere from the manure and flatulence of livestock. A study conducted by the German Bundestag which found that 80 percent of methane released into the atmosphere comes from livestock wastes (The Swiss Union for Vegetarianism 1998).  Thus, by eliminating livestock production, the relative amount of methane in the atmosphere would drastically decrease.  It is important to note that methane has 11 times the global warming capacity of carbon dioxide (Connor 1998). Since its concentration in the atmosphere is significantly smaller than that of carbon dioxide, even a small reduction would have a large impact (Teisler-Rice 1998). Furthermore, methane returns to the earth in precipitation and can negatively affect land and aquatic ecosystems. 

 

Deforestation

 FIGURE 3: Change in pasture and forest cover, Central America, 1965-1988

Source: Modified from Durning 1991

Deforestation is a leading cause of many environmental problems present today.  The land used to grow livestock feed, as well as that used for grazing, was in many cases old growth forest originally.  Each year forests are converted to cropland, and the crops that replace the old growth trees do not process as much carbon dioxide as their predecessors, contributing to the greenhouse effect.

Deforestation also leads to “increased runoff, more destructive flooding, and greater soil erosion.” (Brown 1996).  Earthcare (1998) notes that in South and Central America, 5 million acres of rain forest are felled each year to create pastures (Figure 3).  The fertile, biologically diverse forest is destroyed in order to produce inexpensive beef, primarily for the United States  Since the Amazon rain forests provide thirty percent of the world's oxygen, this destruction has a global impact (Lahmer 1996).  In the United States, over half of our trees have been cut down to plant crops in the last three centuries.  These crops are used in a large part to feed livestock (The Vegetarian Society, Inc. 1998).

 

Crop allocation

 

Commodity

Use

Million tons

Percent of total

Growth Rate

 

feed

631.6

44.55

2.0

Cereal

food

786.2

55.45

2.4

 

total

1417.8

 

2.3

 

feed

345.3

51.85

2.0

Grains

food

320.6

48.15

2.1

 

total

665.9

 

2.1

Coarse

feed

303.3

79.31

1.5

Grains

food

79.1

20.69

0.4

 

total

382.4

 

1.6

TABLE 2: Utilization of cereals, 1986. 

Source: Modified from United Nations (FAO) 1989

 

One of  the less obvious but most drastic causes of environmental damage is the use of land to raise livestock feed instead of food for human consumption.  Not only is the land depleted of its minerals, but growing feed grain also uses a significant amount of water.  In California, the United States’ leading dairy state, feed production accounts for almost one-third of all water used for irrigation.  These crops are grown on land that was once forests or prairies or which could be used to grow crops for human consumption (Durning 1991). 

Marcus (1998) cites a study which found that 38 percent of the grain raised around the world is used to fatten livestock, which is a lower estimate than that of the United Nations’ estimated 52 percent (Table 2).  The calories in this grain could sustain nearly 10 billion people (Teisler-Rice 1996). Grain alone cannot provide a nutritionally balanced diet, but the land currently used to grow feed could easily be used for other crops.  Some, like Dr. Carl Phillips of the University of Michigan, may argue that world hunger stems from “local shortages of wealth, not global shortages of food” (Marcus 1998).  Yet by eliminating livestock subsidization by governments of wealthy countries, funds would be freed up that might be used to feed poor areas of the world.  Phillips emphasizes that distribution of crops is a primary setback in feeding the world’s population, and few additional crops need to be grown.  Thus much of the land used to grow feed could be returned to its original state (primarily forests) which would in turn preserve biodiversity and reduce carbon dioxide in the atmosphere. 

 

Conclusion

            By looking at the state of the world today, it becomes apparent that the production of meat is harmful to the environment in many ways.  If livestock raised for human consumption were phased out, and the land used for grazing were returned to its original state, the world would benefit.  Not only would the atmosphere and water be more clean, the soil would retain its naturally fertile top layer.  The world’s growing population would be more easily fed using funds once devoted to livestock subsidies.

One of the greatest benefits stemming from the elimination of animal products in the human diet is the preservation of biodiversity.  By returning range land and feed crop land to their natural states, both plants and wildlife would be able to reclaim the land they require for migration, feeding, and reproducing.  Currently range land is fenced off, not only keeping the cattle in, but keeping the wildlife out.  While this is deemed necessary by ranchers, the processes of nature are interrupted (Marcus 1998). 

Maintaining biodiversity for these somewhat moral reasons may not seem pragmatic.  However, biological diversity has many implications that affect even the most self-interested humans.  Tropical rain forests of Central and South America are home to millions of species of plants and animals, most of which have not been identified and catalogued.  Because these forests are populated by such a large number of species, it is especially critical to preserve them (Srivastava 1996).  In converting an acre of rain forest to crop land, an entire species might be eliminated.  This is significant because there is potential untapped medicinal value in plants in these areas (Srivastava 1996).  This is simply another example of how the land has much more to offer than simply crops and livestock.

Man is indeed an amazing animal.  His interests lie more heavily on the dinner table than in the well being of those who will inherit his leftovers.  Each hamburger consumed has an impact reaching far beyond its source.  While the global elimination of meat from the human diet is not likely under the current popular opinion, in may become necessary as natural resources on Earth are contaminated and depleted.

 

About the Author

            Katharyn Jeffreys has a Bachelors degree in Environmental Engineering at the Massachusetts Institute of Technology in Cambridge, MA.  She has been a vegetarian for over seven years.

 

References

Brown, Lester R.  Tough Choices. New York: W. W. Norton, 1996.

Connor, Steve. “The Environmental Impact of Meat.” <http://www.vegsoc.org/Campaign/meatimp.html>

(9 Nov 1998).

 

Cox, George W. and Atkins, Michael D.  Agricultural Ecology.  San Francisco: W. H. Freeman, 1979

 

Durning, Alan B. and Holly B. Brough. Worldwatch Paper 103: Taking Stock: Animal Farming and the

Environment. Worldwatch Institute, July 1991.   

 

Earthcare. “Environmental Protection, Conservation, Biodiversity”  <http://www.earth.org.hk/eng-greenissues.html>

(9 Nov 1998).

 

Harkin, Tom.  Animal Waste Pollution in America: An Emerging National Problem. Comp. Minority Staff of the

United States Committee on Agriculture, Nutrition, & Forestry.  December 1997.

 

Harris, Mark.  “How Green is your plate? A plant based diet takes a smaller bite out of the environment.”      Vegetarian Times 228 (1996): 56.

 

Lahmer, Reuel. “Trees.” 1996. <http://www.ivu.org/evu/news961/trees.html> (9 Nov 1998).

 

Marcus, Erik.  Vegan: The New Ethics of Eating.  New York:  McBooks Press, 1998.

 

Messina, Virginia K. and Kenneth I. Burke. “Position of The American Dietetic Association: Vegetarian  diets.”

<http://www.eatright.org/adap1197.html> (9 Nov  1998).

 

Mindel, Eric.  “Comparing Foods’ Vitamin Content.”  <http://www.vegweb.com/articles/vitamins.shtml> (9 Nov

1998).

 

National Cattlemen's Beef Association.  “12 Myths & Facts About Beef Production.”

<http://www.beef.org/librfacts/myths_facts.htm> (1 Dec 1998).

 

Physician’s Committee for Responsible Medicine. “Calcium in Plant Based Diets.”

<http://pcrm.org/health/VSK/VSK5.html> (9 Nov 1998).

 

Srivastava, Jitendra, et al.  World Bank Technical Paper Number 321: Biodiversity and Agriculture: Implications for

Conservation and Development.  Washington, D.C.: The World Bank, 1996.

 

Swiss Union for Vegetarianism. “The Ecological and Economical Consequences of a Meat Orientated Diet.”

<http://www.vegetarismus.ch/info/eoeko.htm> (9 Nov 1998).

 

Teisler-Rice, Pamela.  “101 Reasons Why I Am Vegetarian (1996 Edition).”

<http://www.earthbase.org/vivavegie/vv101/101reas96.html>  (9 Nov 1998).

 

---. “101 Reasons Why I Am Vegetarian (1998 Edition).” <http://www.earthbase.org/vivavegie/vv101/101reas98.html>  (9 Nov 1998).

 

United Nations.  Food and Agriculture Organization.  Commodities and Trade Division.  “Aspects of the world feed-

livestock economy.” FAO: Rome, 1989.

 

United States Department of Agriculture. National Agricultural Library. Food and Nutrition Information  Center. 

“The Food Guide Pyramid: A Guide to Daily Food Choices.” <http://www.nal.usda.gov:8001/py/pmap.htm> 

(9 Nov 1998).

 

Vegetarian Society, Inc. “The Link between Vegetarianism and Environmentalism.”

<http://www.veg-inc.org/reference/ref_envinfo.htm> (9 Nov 1998).