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Environmental vegetarianism is the practice of vegetarianism or veganism based on the indications that animal production, particularly by intensive farming, is environmentally unsustainable.〔(New York Time's Article: Rethinking the Meat-Guzzler )〕 The primary environmental concerns with animal products are pollution—including greenhouse gas emissions (GHG)—and the use of resources such as fossil fuels, water, and land. ==Environmental impact of meat production== (詳細はmonoculture is harvesting large quantities of a single food species, such as maize or cattle. Monoculture is commonly practiced in industrial agriculture, which is more environmentally damaging than sustainable farming practices such as organic farming, permaculture, arable, pastoral, and rainfed agriculture.〔Public health benefits of strategies to reduce greenhouse-gas emissions: food and agriculture http://www.sciencedirect.com/science/article/pii/S0140673609617530〕 According to the 2006 Food and Agriculture Organization of the United Nations (FAO) report ''Livestock's Long Shadow'', industrialized 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.〔Augenbraun, H., E. Mathews and D. Sarma. 1997. The global methane cycle. http://icp.giss.nasa.gov/education/methane/intro/cycle.html〕 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.〔EPA. 2011. Inventory of U.S. greenhouse gas emissions and sinks: 1990-2009. United States Environmental Protection Agency. EPA 430-R-11-005. 459 pp.〕 Data of a United States Department of Agriculture (USDA) study indicate that about 0.9 percent of energy use in the United States is accounted for by raising food-producing livestock and poultry. In this context, energy use includes energy from fossil, nuclear, hydroelectric, biomass, geothermal, technological solar, and wind sources. The estimated energy use in agricultural production includes embodied energy in purchased inputs.〔Canning, P., A. Charles, S. Huang, K. R. Polenske, and A Waters. 2010. Energy use in the U. S. food system. USDA Economic Research Service, ERR-94. 33 pp.〕 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. Another agricultural effect is on land degradation. Cattle are a known cause for soil erosion through trampling of the ground and overgrazing.〔C.Michael Hogan. 2009. (Overgrazing ). Encyclopedia of Earth. Sidney Draggan, topic ed.; Cutler J. Cleveland, ed., National council for Science and the Environment, Washington DC〕 Much of the world's crops are used to feed animals. With 30 percent of the earth's land devoted to raising livestock,〔Livestock Grazing- Combats or Spreads Desertification? http://www.kkl.org.il/kkl/english/main_subject/curb%20global%20warming/livestock%20grazing-combats%20or%20spreads%20desertification.x〕 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. 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.〔Bharati et al. 2002. Agroforestry Systems 56: 249-257〕 Corn and soybean crops commonly provide food for human consumption, biofuels, livestock feed, or some combination of these. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「environmental vegetarianism」の詳細全文を読む スポンサード リンク
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