Environmental vegetarianism is the practice of vegetarianism or eating a plant-based diet based on the indications that animal-based industries are environmentally destructive or unsustainable. The primary environmental concerns with animal products are pollution—including greenhouse gas emissions (GHG)—deforestation, and the use of resources such as fossil fuels, water, and land.
Environmental impact of animal products
Four-fifths of agricultural emissions arise from the livestock sector.
Estimates on greenhouse gas (GHG) emissions attributable to animal products range from 18% to 51% of total global emissions.
However, a PNAS model showed that even if animals were completely removed from U.S. agriculture and diets, U.S. GHG emissions would be decreased by 2.6% only (or 28% of agricultural GHG emissions). This is because of the need replace animal manures by fertilizers and to replace also other animal coproducts, and because livestock now use human-inedible food and fiber processing byproducts. Moreover, people would suffer from a greater number of deficiencies in essential nutrients although they would get a greater excess of energy, possibly leading to greater obesity.
A 2017 study published in the journal Carbon Balance and Management found animal agriculture's global methane emissions are 11% higher than previous estimates based on data from the Intergovernmental Panel on Climate Change.
A study in Climate Change concluded "if ... average diets among UK adults conformed to WHO recommendations, their associated GHG emissions would be reduced by 17 %. Further GHG emission reductions of around 40% could be achieved by making realistic modifications to diets so that they contain fewer animal products and processed snacks and more fruit, vegetables and cereals."
According to the 2006 Food and Agriculture Organization of the United Nations (FAO) report Livestock's Long Shadow, animal agriculture contributes on a "massive scale" to global warming, air pollution, land degradation, energy use, deforestation, and biodiversity decline. The FAO report estimates that the livestock (including poultry) sector (which provides draft animal power, leather, wool, milk, eggs, fertilizer, pharmaceuticals, etc., in addition to meat) contributes about 18 percent of global GHG emissions expressed as 100-year CO2 equivalents. This estimate was based on life-cycle analysis, including feed production, land use changes, etc., and used GWP (global warming potential) of 23 for methane and 296 for nitrous oxide, to convert emissions of these gases to 100-year CO2 equivalents. The FAO report 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".
Some sources disagree with some of the figures used in arriving at the FAO estimate of 18 percent. For example, the FAO report estimates that 37 percent of global anthropogenic methane emissions are attributable to the livestock sector, and a NASA summary indicates about 30 percent. Because of the GWP multiplier used, such a difference between estimates will have a large effect on an estimate of GHG CO2 equivalents contributed by the livestock sector. Livestock sources (including enteric fermentation and manure) account for about 3.1 percent of US anthropogenic GHG emissions expressed as CO2 equivalents. This estimate is based on methodologies agreed to by the Conference of Parties of the United Nations Framework Convention on Climate Change.
A 2010 report from the United Nations Environment Programme's (UNEP) International Panel of Sustainable Resource Management stated:
Impacts from agriculture are expected to increase substantially due to population growth and increasing consumption of animal products. Unlike fossil fuels, it is difficult to look for alternatives: people have to eat. A substantial reduction of impacts would only be possible with a substantial worldwide diet change, away from animal products.
According to Cornell University scientists: "The heavy dependence on fossil energy suggests that the US food system, whether meat-based or plant-based, is not sustainable". However, they also write: "The meat-based food system requires more energy, land, and water resources than the lactoovovegetarian diet. In this limited sense, the lactoovovegetarian diet is more sustainable than the average American meat-based diet." One of these Cornell scientists has advised that the US could feed 800 million people with grain that livestock eat. He "depicted grain-fed livestock farming as a costly and nonsustainable way to produce animal protein", but "distinguished grain-fed meat production from pasture-raised livestock, calling cattle-grazing a more reasonable use of marginal land".
According to a 2002 paper:
The industrial agriculture system consumes fossil fuel, water, and topsoil at unsustainable rates. It contributes to numerous forms of environmental degradation, including air and water pollution, soil depletion, diminishing biodiversity, and fish die-offs. Meat production contributes disproportionately to these problems, in part because feeding grain to livestock to produce meat—instead of feeding it directly to humans—involves a large energy loss, making animal agriculture more resource intensive than other forms of food production. ... One personal act that can have a profound impact on these issues is reducing meat consumption. To produce 1 pound of feedlot beef requires about 2,400 gallons of water and 7 pounds of grain (42). Considering that the average American consumes 97 pounds of beef (and 273 pounds of meat in all) each year, even modest reductions in meat consumption in such a culture would substantially reduce the burden on our natural resources.
A 2003 paper published in the American Journal of Clinical Nutrition, after calculating effects on energy, land, and water use, concluded that meat-based diets require more resources and are less sustainable than lacto-ovo vegetarian diets. "The water required for a meat-eating diet is twice as much needed for a 2,000-litre-a-day vegetarian diet".
Another agricultural effect is on land degradation. Cattle are a known cause for soil erosion through trampling of the ground and overgrazing. Much of the world's crops are used to feed animals. With 30 percent of the earth's land devoted to raising livestock, a major cutback is needed to keep up with growing population. Demand for meat is expected to double by 2050; meat consumption is steadily rising in countries such as China that once followed more sustainable, vegetable-based diets.This is because, as countries are developing, incomes are increasing so the demand for animal products are seen as a luxury many can now afford. The demand for animal products is quickly increasing; "74 percent for meat, 58 percent for dairy products and 500 percent for eggs". This growing demand is unsustainable.
The environmental impacts of animal production vary with the method of production. A grazing-based production can limit soil erosion and also allow farmers to control pest problems with less pesticides through rotating crops with grass. However, in arid areas, this may catalyze a desertification process. The ability of soil to absorb water by infiltration is important for minimizing runoff and soil erosion. Researchers in Iowa reported that a soil under perennial pasture grasses grazed by livestock was able to absorb far more water than the same kind of soil under two annual crops: corn and soybeans. Corn and soybean crops commonly provide food for human consumption, biofuels, livestock feed, or some combination of these.
Animal production has a large impact on water pollution and usage. According to the Water Education Foundation, it takes 2,464 gallons of water to produce one pound of beef in California, whereas it takes only 25 gallons of water to produce one pound of wheat. Raising a large amount of livestock creatives a massive amount of manure and urine, which can pollute natural resources by changing the pH of water, contaminates the air, and emits a major amount of gas that directly affects global warming. As most livestock are raised in small confined spaces to cut down on cost, this increases the problem of concentrated waste. Livestock in the United States produces 2.7 trillion pounds of manure each year, which is ten times more than what is produced by the entire U.S. population. There are issues with how animal waste is disposed, as some is used as fertilizer while some farmers create manure lagoons which store millions of gallons of animal waste which is extremely unsafe and detrimental to the environment.
In November 2017, 15,364 world scientists signed a Warning to Humanity calling for, among other things, drastically diminishing our per capita consumption of meat. A May 2018 study stated that while wildlife has been decimated since the dawn of human civilization, with wild mammals plummeting by 83%, livestock populations reared by humans for consumption have increased. Livestock make up 60% of all mammals on earth, followed by humans (36%) and wild mammals (4%). As for birds, 70% are domesticated, such as poultry, whereas only 30% are wild.
Environmental vegetarianism can be compared with economic vegetarianism. An economic vegetarian is someone who practices vegetarianism either out of necessity or because of a conscious simple living strategy. Such a person may base this belief on a philosophical viewpoint, such as the belief that the consumption of meat is economically unsound or that vegetarianism will help improve public health, lead to global food security, and curb starvation.
Environmental vegetarians call for a reduction of first world consumption of meat, especially in the US. According to the United Nations Population Fund, "Each U.S. citizen consumes an average of 260 lbs. of meat per year, the world's highest rate. That is about 1.5 times the industrial world average, three times the East Asian average, and 40 times the average in Bangladesh." In addition, "the ecological footprint of an average person in a high-income country is about six times bigger than that of someone in a low-income country, and many more times bigger than in the least-developed countries".
The World Health Organization calls malnutrition "the silent emergency", and says that it is a factor in at least half of the 10.4 million child deaths which occur every year. Some[who?] argue that the adoption of an ovo-lacto vegetarian or entirely plant-based vegan diet is best, but may not be totally necessary, because even modest reductions in meat consumption in industrialized societies would substantially reduce the burden on natural resources. For developed countries, a CAST report estimates an average of 2.6 pounds of grain feed per pound of beef carcass meat produced. For developing countries, the estimate is 0.3 pounds per pound. (Some very dissimilar figures are sometimes seen; the CAST report discusses common sources of error and discrepancies among such figures.) In 2007, US per capita beef consumption was 62.2 pounds per year, and US per capita meat (red meat plus fish plus poultry) consumption totaled 200.7 pounds (boneless trimmed weight basis).
Bill Mollison has argued in his Permaculture Design Course that vegetarianism exacerbates soil erosion. This is because removing a plant from a field removes all the nutrients it obtained from the soil, while removing an animal leaves the field intact. On US farmland, much less soil erosion is associated with pastureland used for livestock grazing than with land used for production of crops. However, many crops are used to feed livestock in the meat industry. Robert Hart has also developed forest gardening, which has since been adopted as a common permaculture design element, as a sustainable plant-based food production system.
Some environmental activists claim that adopting a vegetarian diet may be a way of focusing on personal actions and righteous gestures rather than systemic change. Environmentalist Dave Riley states that "being meatless and guiltless seems seductively simple while environmental destruction rages around us", and notes that Mollison "insists that vegetarianism drives animals from the edible landscape so that their contribution to the food chain is lost".
Others assert that "the vegan diet wastes available land that could otherwise be used to feed more people", but still conclude that a dairy-friendly vegetarian diet is the most sustainable when compared to 9 other diets, some more influenced by vegetarianism than others.
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