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The Rise of Veganism: An Environmental Perspective

(Woodyatt, 2019)

Environmentalists have long underscored the meat industry’s environmental impact. Alongside production that has tripled over the last four decades, veganism has become more popular than ever with a global proportion of 1%. In the United States, the number of vegans rose by 600% between 2014 and 2017, and it is estimated that the global vegan industry will reach $13.5B USD by 2026. This is a summary of my AP Seminar Independent Research Report that discerned the environmental impact of meat and vegan alternatives by analyzing GHGEs, land use, water use, and food waste.

(The Economist, 2020)

Greenhouse Gas Emissions (GHGEs)

GHGEs are a critical determinant due to their direct correlation to climate change through the trapping of heat. One study concluded that “food consumed by high meat eaters is associated with 2.5 times more GHGEs than that consumed by a vegan” and “a complete switch to a vegan diet could reduce CO2 by 17%, NO2 by 21%, and CH4 by 24%.” As explored by Petrovic et al. from the Institute of Meat Hygiene and Technology in Serbia, “Beef and dairy farming operations produce the greatest amount of CH4 from human-related activities.”

The high GHGEs associated with the meat industry manifest three-fold. First, animals’ digestion of plants through “enteric fermentation” causes the release of potent gasses and manure byproducts, which contain high concentrations of methane, a gas 80 times more potent than CO2. Secondly, the fertilization of livestock feed requires the application of synthetic fertilizers, which emit high levels of nitrous oxide, a gas 300 times more potent than CO2. Thirdly, significant fossil fuels are required for the processing of meat. A study published in The American Journal of Clinical Nutrition found that broiler chickens are the least energy-demanding, with 4 kcal of fossil energy per kcal of protein, while beef cattle and lamb require 40 kcal and 57 kcal of fossil fuel per kcal of protein respectively.

Though research shows the notable GHGEs associated with the meat industry, these results are diminished by other studies arguing that rather than replacing meat with fruits and vegetables, vegans more commonly compensate with highly processed and energy-demanding substitutes such as seitan burgers and soy yogurt. Other major concerns include agriculture’s mass deforestation, methane from rice, and vegetation’s short lifespan demands refrigeration.

(Dunne, 2020)

Land Use

According to Chai et al., for each gram of beef protein consumed, production demands 42 times more land than staple plant foods (rice, bean, potato, etc.), and livestock farming uses 70% of agricultural land and a third of all arable land. Evidently, intense meat production to meet the demands of omnivorous diets requires extensive land use. Pimentel & Pimentel found that if all meat and dairy products were replaced with plant-based alternatives, land use could be reduced by over 50%. Costa’s study affirms this by concluding the vast amount of land required for meat production not only increases competition within the agriculture industry but also between industries–like tourism and real estate–which also require immense land. This amplifies the tension between preserving natural environments, sustaining biodiversity, and meeting the demands of civilians.

Land use isn’t limited to area, but also the way land is used. The availability of arable and productive soil is decreasing due to the rapidly growing rates of soil erosion, degradation, and land encroachment. In fact, “each year about 90% of US cropland loses soil at a rate 13 times above the sustainable rate of 1 ton/ha/y.” Overgrazing and erosion are exacerbated by popularizing practices like genetically modified organisms (GMOs) and pesticide overuse. Marlow et al., affirms stating that non-vegetarian diets use “13 times more fertilizer and 1.4 times more pesticides,” contributing to land pollution and biodiversity loss.

However, one argument that diminishes the preceding arguments is that the increasing number of vegans is coupled with harmful practices of deforestation and monoculture. Specifically practiced for staple crops, deforestation results in catastrophic environmental damage, and the death of thousands of animals and plants. One study found that “at least 25 times more sentient animals [are] being killed per kilogram of useable protein” due to decreasing availability of arable land and “at least 55 sentient animals die to produce 100 kg of usable plant protein.” Additionally, the dominant practice of monoculture–employed on 442 million acres in the U.S.–exacerbates lack of crop biodiversity and decreases soil nutrition.

Water Use and Waste

Water is used in all stages of meat processing. One study concluded that a kilogram of beef and a non-vegetarian diet requires 18 times and 2.9 times more water than a vegetarian diet respectively. Another study showed that a “vegan diet makes the lightest demands on the global water supply, requiring 14.4% less freshwater and 20.8% less ground water than the omnivorous diet.” In the U.S., agricultural production demands more freshwater than any other activity. However, when studying the data analysis from Ritchie & Roser in Our World in Data, variability is evident. It is imperative to not generalize “meat” and “vegetables” as water use greatly differs for specific food products. For example, per 1000 kilocalories of food product, tomatoes require almost twice the amount of freshwater than beef, which is the most water-consuming meat product, while if 100 grams of protein per food product were to be analyzed, nuts require almost twice the amount of freshwater than beef.

When analyzing water use, it is also important to observe production chains. Though livestock uses 1.3% of the total water used in agriculture, this statistic doesn’t consider the water used for forage and animal feed animal production. According to a paper from the Journal of Cleaner Production, “producing 1 kg of fresh beef may require about 13 kg of grain and 30 kg of hay.” and “on rangeland for forage production, more than 200,000 L of water are needed to produce 1 kg of beef.”

Another aspect of water use is waste. For meat production, this is caused by the “washing of livestock, carcasses and offal, cleaning of equipment and factories, workers’ personal hygiene, and truck washing.” Improper disposal of aqueous byproducts results in pollutants in the form of blood, fat, manure, undigested stomach contents, dirt, and cleaning agents. Slurry–the liquid form of manure–contains high levels of nitrous oxide, nitrate, and ammonia, which contributes to eutrophication and pollution. In fact, “78% of the global ocean and freshwater eutrophication is caused by agriculture,” demonstrating the significant environmental footprint of meat from a water perspective.

Food Waste

The two main types of solid waste include inedible products, such as bones, fat, heads, legs, skins, hair and offal, and packaging materials, mainly paper, plastic, and metal. Multiple studies have shown that waste produced by plant-based diets is a lot more climate-friendly than other food products. A study by Dr. Djekic from the University of Belgrade states “that fruits and vegetables which comprise 33% of food waste, account for only 8% of carbon dioxide emissions. Animal-based foods, in contrast, account for 33% of food waste by mass and 74% of carbon dioxide emissions.” Using this evidence, it is important to understand the different inputs and outputs of different components in a diet.


The environmental impact of veganism compared to omnivorous diets was explored using four overarching factors. Through this analysis, it was concluded that vegan diets have a significantly lower environmental footprint, however, certain variables diminish this conclusion. Future research should look into consumption rates of meat compared to plant-based alternatives, and the environmental impact of these alternatives, as vegan diets encompass many food products beyond fruits and vegetables. For example, one study found that chickpea-based mayo had a significantly higher environmental footprint than egg-based mayo due to high chemical and electricity input, while also concluding that legume pasta emits 35.5% less GHGEs than egg-based pasta. Observations of the environmental implications posed by different diets should be further explored as it’s imperative for guiding sustainable lifestyle shifts, the development of agriculture programs, and innovation within food science.


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