Environmental vegetarianism is the practice of vegetarianism when motivated by the desire to not contribute to the negative environmental impact of meat production. Livestock as a whole is estimated to be responsible for around 15% of global greenhouse gas emissions. As a result, significant reduction in meat consumption has been advocated by, among others, the Intergovernmental Panel on Climate Change and as part of the 2017 World Scientists' Warning to Humanity.
Other than climate change, environmental concerns about the production of animal products may also relate to pollution, deforestation, unsustainability and the use of water and land.
Environmental impact of animal products
Four-fifths of agricultural emissions arise from the livestock sector.
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".
A 2009 study by the Worldwatch Institute
argued that the FAO's report had underestimated impacts related to
methane, land use and respiration, placing livestock at 51% of total
global emissions.
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.
The environmental impacts of animal production vary with the method
of production, although "[overall] impacts of the lowest-impact animal
products typically exceed those of vegetable substitutes".
Methane
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.
Land use
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".
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".
Land degradation
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;
in China, for example, where vegetable-based diets were once the norm,
demand for meat will continue to be great in absolute terms, even though
demand growth will slow.
As countries are developing, incomes are increasing, and consumption of
animal products is associated with prosperity. This growing demand is
unsustainable.
A grazing-based production can limit soil erosion and also allow
farmers to control pests with less pesticides by 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.
Biodiversity loss
The 2019 IPBES Global Assessment Report on Biodiversity and Ecosystem Services found that the primary driver of biodiversity loss
is human land use, which deprives other species of land needed for
their survival, with the meat industry playing a significant role in
this process. Around 25% of earth's ice-free land is used for cattle
rearing. Other studies have also warned that meat consumption is accelerating mass extinctions globally. A 2017 study by the World Wildlife Fund attributed 60% of biodiversity loss to the land needed to rear tens of billions of farm animals.
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 the biomass 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.
Water
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.
Relation to other arguments
Massive reductions in meat consumption in industrial nations will ease the health care burden while improving public health; declining livestock herds will take pressure off rangelands and grainlands, allowing the agricultural resource base to rejuvenate. As populations grow, lowering meat consumption worldwide will allow more efficient use of declining per capita land and water resources, while at the same time making grain more affordable to the world's chronically hungry.Worldwatch Institute, an independent environmental research institute
Although motivations frequently overlap, environmental vegetarians
and vegans can be contrasted with those who are primarily motivated by
concerns about animal welfare (one kind of ethical vegetarianism), health, or who avoid meat to save money or out of necessity (economic vegetarianism). Some also believe vegetarianism will improve global food security, or curb starvation.
Health
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." A study in The Lancet
estimated that the "30% reduction in livestock production" by 2030
required to meet the UK Committee on Climate Change's agricultural would
also result in a roughly 15% decrease in ischaemic heart disease.
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 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).
Support
A 2018 report in Nature
found that a significant reduction in meat consumption is necessary to
mitigate climate change, especially as the population rises to a
projected 10 billion in the coming decades. According to a 2019 report in The Lancet, global meat consumption needs to be reduced by 50 percent to mitigate for climate change.
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 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.
The aforementioned Global Assessment Report on Biodiversity and Ecosystem Services also suggested that a reduction in meat consumption would be required to help preserve biodiversity.
Criticism
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. 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".
A PNAS model showed that if animals were completely removed from
U.S. agriculture and diets, U.S. GHG emissions would only be decreased
by 2.6% (or 28% of agricultural GHG emissions). This conclusion is on
the basis that, in the absence of animal manure from animal agriculture,
synthetic fertilizers would have to be produced, in order to meet a
plant based global food demand, which releases GHG emissions.
The study also contributes this to the disposal of byproducts, which
would otherwise be used as domesticated animal feed, and emissions from
growing crops on land previously used to rear agricultural animals.
Moreover, it is suggested that a conversion of the global population to a
plant based diet
may increase rates of nutrient deficiencies, particularly in the US,
because the types of crops suitable to be grown on US climate and soils
may not be sufficient for a balanced diet.