The Vegetarian Solution to Water Pollution

Based on the United Nations Report "Livestock's Long Shadow"

In 2006, the United Nations released a report assessing livestock raising and its impact on the environment. Henning Steinfeld, senior author of this report, announced, “Livestock are one of the most significant contributors to today’s most serious environmental problems.… Urgent action is required to remedy the situation.”

Livestock’s Long Shadow: Environmental Issues and Options represents a breakthrough in the literature on animal agriculture as it relates to environmental issues. This report directly establishes and quantifies causeeffect relationships between livestock production and environmental problems on a problem-by-problem basis on a global level. With Livestock’s Long Shadow, an international body clearly shows the connection between diet and major environmental problems.

In light of a projection that global meat production will more than double by 2050, Livestock’s Long Shadow warns, “The environmental costs per unit of livestock production must be cut by one half, just to avoid increasing the level of damage beyond its present level.” In June 2008, Yvo de Boer, head of the United Nations Framework Convention on Climate Change (UNFCCC), summed up a way to solve this problem quickly. He said, “The best solution would be for us all to become vegetarians.”

In this Vegetarian Journal article, The Vegetarian Resource Group (VRG) examines the information covered in Livestock’s Long Shadow, Chapter Four, which is titled “Livestock’s Role in Water Depletion and Pollution.”


The U.N. notes that most decision-makers work under the assumption that a very small estimate (< 1 percent) of all freshwater is used by livestock (mostly for drinking). The report asserts that this is “a considerable underestimate” of the actual amounts that raising livestock, both directly and indirectly, uses over all stages of production. Besides water for drinking and servicing animals (e.g., cleaning and cooling facilities, washing animals, and flushing waste), there are many other ways that livestock production uses water. The major ones include slaughtering, meat and milk processing, and leather tanning, all of which “result in high water usage and consequently high wastewater generation.”

The major indirect water use in livestock production is irrigation water, which is used to grow the feedcrops that support animal agriculture. Taking this indirect water use into consideration, the U.N. report cited estimates “that the livestock sector may account for some 45 percent of the global budget of water used in food production.”


Most of the freshwater that the livestock industry uses goes back into the environment as manure and wastewater (pollution). Pollution is divided into two groups: ‘point’ and ‘non-point’ source pollution.

  • Point Source Pollution

    Point source pollution usually comes from a discharge pipe and goes directly into a waterway. Livestock’s Long Shadow states that intensive animal production is becoming commonplace all over the world. Operations concentrate large numbers of animals into small areas that cannot support their cultivation. In developed countries such as the United States, where regulations may exist, “rules are often circumvented or violated.” In developing countries where most intensive animal operations are close to cities, direct discharge of animal wastes into waterways is very common. If regulations are in place, they are often not enforced. As a result, the lack of data makes a global assessment of livestockgenerated point source pollution impossible.

    Livestock processing at slaughterhouses pollutes water locally through direct discharge of wastewater into waterways or through surface runoff. This is true especially in developing countries because slaughterhouses are usually located in populated areas without appropriate rendering and waste treatment facilities.

  • Non-Point Source Pollution

    Non-point source pollution is spread over a wide area (e.g., manure spreading on fields). The ‘principal’ non-point source water pollutant related to agriculture is soil erosion, such as through hoof and grazing impacts on pastures and rangelands. Each year, erosion sends 25 billion tons of sediments into waterways, and the sediments are not replaced easily or quickly. (Natural replacement takes hundreds of years.) Without rich or sufficient topsoil, farmers begin a cycle of adding chemical fertilizers to get what soil they do have to produce high grain yields. In the process, they end up destroying the land even further.

    Nutrients and chemicals reach waterways by leaching, surface runoff, and soil erosion. Estimates of the costs needed to correct some of the problems (e.g., controlling erosion or removing nitrates from drinking water) range in the millions or even billions of dollars every year.

    Both point source pollution and non-point source pollution contain large amounts of substances that were not initially present in the water before it was used for agricultural purposes. These substances include nutrients (especially nitrogen and phosphorus, which are chemicals often found in fertilizers), disease-causing agents (such as bacteria), drug residues, and heavy metals (e.g., lead).

    Water may be contaminated with large amounts of nitrogen and phosphorus when fertilizer is applied to fields. In addition, the U.N. report points out that approximately 75 percent of the nitrogen and phosphorus that farm animals eat they eventually excrete as waste. The report estimates that, each year, grazing cattle add millions of tons of nitrogen and phosphorus to the environment through their manure. This value is “greatly underestimated” because it represents only “pure” grazing systems, not systems where livestock spend part of the year on feedlots.

    Both fertilizer and animal waste introduce a huge surplus of these nutrients into an environment that cannot easily handle them. These excesses degrade surface water (e.g., streams and lakes) as well as groundwater (e.g., wells). Fresh waterways become damaged or die because too much algae form on their surfaces. In addition, high levels of nitrogen in water, in the form of nitrates, are known public health hazards. In the United States, 4.5 million people drink well water containing nitrates above the accepted standards. Other public health hazards include large numbers of bacteria (e.g., Salmonella and E. coli), viruses, and parasites.

    Drug residues, especially antibiotics and hormones found in manure and wastewater, also contaminate freshwater. Livestock’s Long Shadow states that at least half of all antibiotics produced in the United States is used on animals and that 80 percent of antibiotics used in the livestock industry is administered for disease prevention and growth promotion. The animals who drink the contaminated fresh water and even the humans who consume resulting meat products can develop a bacterial resistance. This renders antibiotics ineffective when sick animals or people really need them. Furthermore, hormones, which are commonly released into the environment through manure and wastewater, have negative effects in wildlife, including sex reversals in fish, and contribute to higher rates of certain cancers in both wildlife and humans.


There are two major ways by which animal agriculture influences the water cycle (i.e., the never-ending movement of water on, above, and below the earth as vapor, rain/snow, or liquid water):

  • Extensive grazing is responsible for degrading 70 percent of rangelands throughout the world. The degradation occurs when the animals repeatedly trample the earth and lowers the amount of water available throughout the region. Grazing also negatively influences the natural vegetation, reducing the number of plant types as well as their quantity.
  • Land conversion heavily influences the water cycle. The livestock sector is responsible for converting large areas of pasture into land used to grow feedcrops and for clear-cutting forests to make way for feedcrops. This has happened in the Amazon basin in South America. Global rainfall patterns are likewise affected.


The U.N. report describes several approaches that could result in reducing water pollution caused by livestock production. Some of these include the following:

  • Improving irrigation efficiency (i.e., less irrigation water is wasted)
  • Boosting water productivity (e.g., increasing crop yield)
  • Improving waste management through technological options (e.g., using readily absorbable feed ingredients that aren’t excreted or enzyme/vitamin supplementation)
  • Improving manure collection processes (e.g., better animal housing design, manure storage, and manure processing improvements)
  • Improving manure utilization practices (e.g., timely manure dosing on farmland done in accordance with crop requirements)
  • Properly controlling grazing season

Chapter 4 of Livestock’s Long Shadow concludes by pointing out that these technical options are not widely applied. Since they are long-term solutions, they are not viewed by the livestock industry as “cost effective.” The report calls for a policy framework of environmental standards by which the listed strategies could be effective.

In Chapter 6, titled “Policy Challenges and Options,” the report suggests better ways of using water, such as introducing full-cost pricing for water


In April 2008, the Union of Concerned Scientists (UCS) published a comprehensive report on confined animal feeding operations (CAFOs) titled CAFOs Uncovered: The Untold Costs of Confined Animal Feeding Operations. It examined ways of reducing the impact of animal agriculture on water. The Pew Commission on Industrial Farm Animal Production, funded by the Pew Charitable Trusts, published a similar document titled Putting Meat on the Table: Industrial Farm Animal Production (IFAP) in America in May 2008. Both of these documents generally followed Livestock’s Long Shadow in scope but analyzed the problem on a national level rather than on a global scale.

All three of the reports are alike in that animal agriculture is identified as a major source of water pollution and depletion. They differ with regard to the amount of importance placed (1) on various ways of reducing water pollution most effectively and maintaining a clean water supply most sustainably, and (2) on reasons given as to why animal agriculture has become such an intensive business. For instance, the UCS report shows that the confinement system is “driven … by the market power held by large processors” and “deliberate government policies that cost taxpayers billions every year.” On the other hand, the Pew report “firmly believes that many of the problems associated with IFAP are unintentional.” Because of differing premises, the two U.S. reports reach somewhat different conclusions.

(i.e., no free or reduced-cost water, especially to the agricultural industry) and taxes to discourage large-scale livestock concentration close to cities. It also advises the removal of “perverse” subsidies that devalue water, the development of legal water rights, and the development of an economic water market. Included among the proposals for better water pollution control are the establishment of water quality standards and enforced control measures, as well as the decentralized industrial production of livestock (i.e., fewer large operations).


The U.N. report shows that livestock’s contribution to water scarcity and pollution is “on a massive scale”; it, as well as all major environmental issues, “needs to be addressed with urgency.” However, the report asserts that the damage that livestock production does to water, and to all of our natural resources, can be only “partially offset” by scientific knowledge and technological capability.

The report states that “ultimately environmental issues are social issues.” It discusses how future generations and even the survival of the planet as a whole depend on how countries negotiate and allocate “common” resources, such as water that runs through two or more countries and thereby serves as grounds for political and legal conflicts, especially in times of water scarcity and pollution. The Food and Agriculture Organization (FAO) predicts that two-thirds of the global population will face water shortages by 2025. That’s more than today’s 1.2 billion people who live in areas with insufficient and/or polluted water.


Livestock’s Long Shadow discusses the marked increase in meat and milk consumption, often as fast food, among people with rising incomes, and these consumption patterns have been observed throughout the world. Increasing urbanization has lead to more industrial production of animals, has placed larger demands on natural resources in more concentrated areas, and has created waste disposal issues on a grand scale.

This discussion leads the report’s authors to make direct and indirect references to vegetarianism as an answer to the escalating environmental problems that animal agriculture has created. Even the “Introduction” to the report states that consumers are “increasingly influenced by growing concerns about health, the environment, ethical, animal welfare, and development issues.… A class of ‘concerned consumers’ has emerged who tend to reduce their consumption of livestock food products.… The growing trend towards vegetarianism … is another manifestation of this trend.”

The authors elaborate further on this point in Chapter 6. In that chapter’s last paragraph, they state, “A different pathway to addressing the environmental impact of feedcrop production is to reduce demand.”

Nevertheless, the report, rather than developing the idea that an increase in plant-based diets would reduce demand for livestock production and the crops used to feed livestock, discusses feed efficiency technologies and trade barriers. Absent is a discussion of how much these proposed remedies will cost or who should pay for them. However, it should be noted that the FAO Director-General, Jacques Diouf, has recently called for a minimum of $30 billion per year for “global agricultural restructuring.”

The final chapter of Livestock’s Long Shadow, titled “Summary and Conclusions,” clearly advocates the “reduction in demand.” It states, “While not being addressed by this assessment, it may well be argued that environmental damage by livestock may be significantly reduced by lowering excessive consumption of livestock products among wealthy people. International and national public institutions (e.g., the World Health Organization) have consistently recommended lower intakes of animal fat and red meat in most developed countries.”

The last chapter also asserts a conclusion often discussed by those who argue for vegetarianism based on world hunger concerns: “Livestock actually detract more from total food supply than they provide. Livestock now consume more human edible protein than they produce.… As the livestock sector moves away from using feed … that has no alternative value towards using crops and other high value inputs, it enters into competition with food … it raises overall demand and prices for crops and agricultural inputs.”

In addition, the report directly and positively refers to vegetarianism as a solution to the environmental problems propagated by animal agriculture. It suggests that vegetarianism and eco-labeling are “reasons for optimism that the conflicting demands for animal products and environmental services can be reconciled.… The relatively affluent, middle- to high-level income class, which is no longer confined to industrialized countries ... is probably ready to use its growing voice to exert pressure for change and may be willing to absorb the inevitable price increases. The development of markets for organic products and other forms of eco-labeling are precursors of this trend, as are the tendency towards vegetarianism within developed countries and the trend towards healthier diets.”

Livestock’s Long Shadow is not telling everyone to be vegan. However, in light of the report’s conclusions, some who advocate vegetarianism may call for the elimination of most or all animal food products as a way to solve our environmental problems. These people would agree with Rajendra Pachauri, the Chairman of the Nobel Prize-winning Intergovernmental Panel on Climate Change (IPCC). In September 2007, he was asked, “What do you personally do for climate protection?” He responded, “I have become a vegetarian.”


David Pimentel, Ph.D., is professor of ecology and agricultural science at Cornell University. In 2008, he and his wife Marcia, a lecturer in nutrition at Cornell, published the third edition of Food, Energy, and Society, a book considered by many to be one of the best for information linking overpopulation, energy requirements, and food production.

Pimentel states that, in the U.S. every year, 253 million tons of grain are fed to livestock, requiring a total of 250 x 1012 (250 trillion) liters of water.

This would be like filling up 100 million Olympic-sized swimming pools. (Global figures are three times higher for both grain and water.)

“The amount of grain fed to U.S. livestock [annually] is sufficient to feed 840 million people who are plant-based vegetarians,” Pimentel states. The U.S. population is currently approximately 301 million people.

The table below, based on Pimentel’s work, contains other estimated amounts of water required to produce crops and livestock.

Table 1 - Water (L/kg) Used to Produce Crops and Livestock
Crop or Livestock Water Used (L/kg) Crop or Livestock Water Used (L/kg)
Millet 272 Broiler chicken 3,500
Corn 650 Pig 6,000
Wheat 900 Beef (feedlot) 43,000
Rice 1,600 Beef (rangeland) 120,000 - 200,000
Soybeans 2,000 Milk 990 L/L milk
Note: One kilogram (kg) is approximately equivalent to 2.2 pounds. One liter (L) is approximately equivalent to 1.06 quarts.

Table 2 - Major Findings of the United Nations Food and Agriculture (FAO) Report
  • The livestock sector produces more greenhouse gases (18 percent), as measured in carbon dioxide equivalents, than all cars, trucks, and SUVs combined.
  • The livestock sector is one of the top contributors to water pollution and land degradation.
  • The livestock sector uses
    • 30 percent of the earth's entire land surface for grazing.
    • 70 percent of the earth's agricultural land to produce feed.
    • 8 percent of freshwater.
    • 37 percent of all pesticides used in the United States.
    • 50 percent of all antibiotics used in the United States.
  • The livestock sector produces:
    • 65 percent of human-induced nitrous oxide, a greenhouse gas that is almost 300 times more powerful than carbon dioxide in heating up the globe.
    • 37 percent of methane, a greenhouse gas that is 23 times more powerful than carbon dioxide in heating up the globe.
    • 68 percent of human-induced ammonia, contributing significantly to acid rain.
  • The livestock sector causes
    • deforestation in Latin America, responsible for 70 percent of forests cleared for grazing in the Amazon.
    • 20-70 percent of pasture degradation, resulting in overgrazing, soil loss, soil compaction, and desertification (i.e., when pasture or agricultural land becomes infertile desert).
    • 55 percent of soil erosion in the United States (global figures unavailable).

Table 3 - Water Use and Depletion Facts: United States and World Comparisons
  • Americans use 300-400 L of water/ person/day.
  • Eighty-three other countries report an average below 100 L of water/ person/day.
  • In terms of all freshwater usage in the United States, including that for irrigation of feedcrops for livestock and other crops, 5,700 L of water is used per person per day.
  • Worldwide, the average water usage (including that for irrigation of food eaten), is 1,970 L of water/person/day.
  • Approximately 40 percent of U.S. freshwater is unfit for recreation or as drinking water because of water pollution. (A global figure for water pollution is unavailable.)

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