The following is an excerpt from my master’s thesis, slightly edited for this forum. Special thanks to Dr. Keith McDade, my professor and mentor, for his support and assistance with this project. Enjoy!

INTRODUCTION

In recent years, there has been a growing interest in plant-based diets, including veganism, vegetarianism, and other lifestyle changes that involve a reduction in the consumption of animal products (Baum & Whiteman, 2017). These dietary changes have been proposed as a solution to multiple human health, environmental, and moral issues (Rossi & Garner, 2013, p. 1). This paper explores a subset of these issues utilizing an interdisciplinary approach.

Part 1 provides an overview of the environmental impacts of agriculture and the environmental benefits associated with transitions to plant-based diets. This is followed by an examination of veganism as a moral philosophy and how veganism can act as a strategy for sustainability in Part 2. Altogether, this essay presents a compelling case for not only reducing animal product consumption, but adopting veganism as both a social justice philosophy and a powerful strategy for sustainability. Importantly, this research is primarily relevant for developed countries in the western world. While the science and philosophy discussed here may have implications for developing nations, it is beyond the scope of this paper to thoroughly explore the issue of veganism and plant-based diets in the context of developing nations.

PART 1 — AGRICULTURE, FOOD HARVESTING, AND ENVIRONMENTAL DEGRADATION

Human influence on the planet has grown to unprecedented levels since the advent of the industrial revolution due to a dramatic rise in human population and consumption (Steffen, 2011). This has resulted in global changes and subsequent negative impacts on natural systems, including climate change, large-scale deforestation and land-use change, unsustainable freshwater use in many regions, phosphorus and nitrogen pollution, other types of chemical pollution, biodiversity loss, ocean acidification, marine and aquatic dead zones, and the degradation of ecosystem services (Steffen, 2011). Human systems are also experiencing degradation, including economic losses, human health impacts, declining crop production, and reduced access to freshwater resources due to the interconnected state of natural and human systems (Costanza, 2014; IPCC 2014: Impacts, Adaptation, and Vulnerability). These changes threaten human societies with rapid decline of economic productivity and human wellbeing, ultimately resulting in societal collapse (Steffen, 2011). This leads to the conclusion that humanity must make sweeping changes to our socio-economic-political systems and our relationship to the natural world if we want to avoid societal collapse and create a sustainable global society.

Producing food for humans through agriculture and other types of harvesting (e.g. fishing), while necessary for feeding the large human population, is one of the leading contributors to environmental degradation. In fact, research suggests that agriculture and food harvesting are key drivers of the three most dangerous environmental impacts disrupting the earth system: biodiversity loss, nitrogen cycle disruption, and climate change (Aiking, 2014, p. 485S; Rockström, 2009). According to researchers, between 21% and 24% of global greenhouse gas (GHG) emissions are attributed to agriculture and land-use change (Tubiello, et al., 2015; IPCC 2014: Mitigation). Moreover, agriculture covers roughly half of ice-free land area on Earth and is responsible for 92% of humanity’s freshwater footprint (Tilman and Clark, 2014; Gerber, 2013). Finally, producing food is the leading cause of biodiversity loss (Living Planet Report, 2016; Machovina, 2015). Given this reality, reducing the environmental impact of food production while feeding a growing human population is one of the greatest sustainability challenges of the 21st century.

Previous research has explored both supply-side (e.g. increasing agricultural yields) and demand-side (e.g. reduced food waste; dietary shifts) mitigation measures aimed at reducing environmental impacts of food production and increasing food security. While supply-side measures have been studied more thoroughly, research suggests that demand-side measures offer significantly greater potential for both reducing environmental impacts of food production and increasing food security (Smith, 2013). Possibly the most promising strategy for meeting this sustainability challenge is transitioning towards plant-based diets. Although agriculture as a whole has significant environmental impacts, animal agriculture is substantially more environmentally destructive than crop agriculture (Aleksandrowicz, 2016; Hoekstra, 2012; Machovina, 2015; Tilman & Clark, 2014). This will be explored in more detail in the following sections.

1.1 — Trophic Levels and Entropy

There is a simple explanation for the fact that animal products have significantly and consistently larger environmental impacts than crop products: the inefficiencies in energy transfer between trophic levels due to entropy. The 2nd law of thermodynamics states that systems always trend toward entropy, or disorder. Practically, this means that all systems that use heat to perform work can never be 100% efficient.

In the case of ecological trophic levels, the transfer of energy between trophic levels is highly inefficient. In fact, converting plant calories to animal calories results in only about 10% efficiency, although this depends on the types of crops and animal products (Cassidy, 2013). Currently, 36% of global crop calories are used as animal feed (Cassidy, 2013). Not surprisingly, roughly 80% of agricultural land is utilized for animal product production, yet meat only accounts for 15% of the global human diet (Smith, 2013, p. 2293).

1.2 — Land-use Change and Deforestation

Animal agriculture is the leading cause of deforestation and land-use change (Machovina, 2015). As previously noted, agriculture covers roughly 50% of ice-free land globally (Tilman and Clark, 2014). Moreover, the majority of agricultural land is used for animal agriculture (Cassidy, 2013; Smith, 2013). Animal agriculture makes up most of agricultural land because it requires significantly more land to produce animal products than plant products.

One study found a consistent relationship between animal product consumption and agricultural land-use in which consuming less animal products results in less land being utilized for agricultural purposes. The researchers found that a global vegan diet would require less cropland in the year 2050 than what was needed in 2000, even with significant population growth. Conversely, typical meat-based diets would require up to 52% more cropland in the year 2050 than what was needed in 2000 (Erb, 2016, p. 4). The larger body of literature reflects these findings. A systematic review of the literature that examined 63 studies found that vegan diets had the largest potential for reducing dietary land-use requirements, with 45% reductions compared to typical diets (Aleksandrowicz, 2016). Simply put, consuming crops as opposed to animals has the potential to significantly reduce the amount of land dedicated to agriculture, therefore halting deforestation and likely allowing large areas of the globe to revert to wildlands or natural areas.

1.3 — Nitrogen Pollution

Agriculture is the major driver of nitrogen pollution (Aiking, 2014; Erisman, 2013). This is the result of nitrogen being a key limiting factor for plant growth in the majority of global ecosystems. Modern industrial processes allow humans to create, through the Haber–Bosch process, far more reactive nitrogen than what is typically found in nature (Erisman, 2013). In fact, the human population was physically unable to exceed roughly 3 billion people before the advent of large-scale nitrogen fertilizer application (Aiking, 2014, p. 485S). Due to the inefficiencies inherent in producing animal products, transitioning to plant-based diets has the potential to significantly reduce nitrogen pollution as direct nitrogen pollution from livestock and the need to produce feed crops is gradually reduced. In fact, one study found that a 50% reduction of meat and dairy consumption in Europe would reduce nitrate inputs to surface and groundwater by 40% (Westhoek, 2014, p. 200).

While nitrogen pollution may not receive as much public attention as other environmental issues such as climate change and biodiversity loss, it is a key driver of global environmental impacts (Aiking, 2014; Erisman, 2013). Nitrogen pollution contributes to climate change, biodiversity loss, stratospheric ozone depletion, as well as various human health issues (Erisman, 2013). The rapid expansion of marine dead zones is a particularly troubling issue related to nitrogen pollution.

Marine dead zones occur when coastal marine systems experience significant reductions in dissolved oxygen due to nutrient pollution, particularly nitrogen and phosphorus. Dead zones now impact roughly 250,000 square kilometers, and are one of the primary drivers of marine ecosystem degradation (Diaz and Rosenberg, 2008). While shifting toward plant-based diets has the potential to reduce nutrient pollution (Westhoek, 2014), and is therefore a promising method for addressing dead zones, crop agriculture in general is a major source of nutrient pollution. Consequently, various methods for preventing nutrients from entering marine and aquatic systems (e.g. thick riparian buffers) are necessary for addressing dead zones (Diaz and Rosenberg, 2008, p. 926).

1.4 — Water Resources

Animal product production is a leading driver of both freshwater use and pollution. In fact, animal product production is responsible for 27% of humanity’s water footprint (Hoekstra, 2012, p. 3). The water footprint concept considers both water consumption and pollution. Of interest, research has found that vegetarian diets reduce water footprint by 36% in comparison to typical diets, although this is highly dependent on the types of animal products and plants being produced. Moreover, animal products have consistently higher water footprints than nutritionally equivalent crop products (Hoekstra, 2012, p. 6).

Concentrated Animal Feeding Operations (CAFOs), which produce the vast majority of animal products in western nations, also cause chronic and severe water quality impacts. One study that assessed water quality in a watershed dominated by CAFOs found elevated levels of fecal bacteria, Chlorophyll a, biochemical oxygen demand (BOD), and various nutrients, including ammonia, nitrate, and orthophosphate. These pollutants, and subsequent changes in water chemistry, result in negative human health and ecological impacts (Mallin, 2015). Importantly, both groundwater and surface waters experience negative impacts (Mallin, 2015, p. 10), and there was no significant difference between fecal coliform, ammonium, and nitrate concentrations during rainy and dry periods. This indicates that these impacts are chronic as opposed to only occurring during events that may increase pollution levels, such as during heavy rain (Mallin, 2015, p. 10). Overall, animal agriculture contributes to chronic and severe water use and water pollution.

1.5 — Climate Change

Animal agriculture is responsible for 14.5% of total global greenhouse gas (GHG) emissions (Gerber, et al., 2015, p. 15). In fact, animal agriculture contributes more GHGs than the entire transportation sector globally (EPA, 2016). This sizable impact is due to the fact that animal products contribute considerably more GHG emissions than crop products (Tilman and Clark, 2014). Tilman and Clark utilized 120 Life Cycle Analysis (LCA) publications that analyzed 555 LCAs on 82 types of crops and animal products to calculate GHG emissions associated with various foods (2014, p. 518). For instance, wheat and legumes, two primary crops that replace meat in a dietary shift towards plant-based diets, produce 0.06 and 0.02 grams of CO2 warming equivalent per kilocalorie of food, respectively. Ruminant meat produces 5.6 g/kcal, meaning that ruminant meat is 93 times more carbon intensive than wheat, and 280 times more carbon intensive than legumes. Even eggs, one of the animal products with the lowest emissions, produces 0.59 g/kcal. This means eggs are 10 times more carbon intensive than wheat and 30 times more carbon intensive than legumes (Tilman and Clark, 2014, supplemental table 3).

A separate article that reviewed 63 studies related to dietary GHG emissions found that the most influential factor determining dietary environmental impacts was the proportion of animal-based foods to plant-based foods. Vegan diets reduced dietary GHG emissions by 51% compared to typical diets, and resulted in the largest reductions in GHG emissions of any diet (Aleksandrowicz, 2016). The larger body of scientific literature corroborates these results, indicating that consuming plants is far less carbon-intensive than consuming animal products (Eshel, et al., 2016; Garnett, 2009; Scarborough, et al., 2014; Springmann, et al., 2016).

While this analysis reveals that plant-based diets have significant potential to mitigate GHG emissions, the studies cited here may actually undervalue the climate change benefits of transitioning to plant-based diets. A more thorough analysis requires scrutinizing the chosen timeframe for calculating the global warming potential (GWP) of methane, and considering the sequestration potential of rewilding land currently dedicated to agriculture.

1.5.1 — GWP and Methane

Global warming potential (GWP) is a metric used to compare the relative energy added to the climate for different greenhouse gases by using carbon dioxide as a baseline. The Intergovernmental Panel on Climate Change (IPCC) produces GWPs for 20-year and 100-year timeframes. A 20-year GWP considers the energy absorbed by the gas over 20 years, while a 100-year GWP considers the energy absorbed by the gas over 100 years. Methane is a powerful GHG that breaks down after just a few decades. This means that the 20-year GWP for methane is much higher than the 100-year GWP. In the most current IPCC report, the 20-year and 100-year GWPs for methane were 86 and 34, respectively (IPCC, 2013).

The 100-year GWP is typically used in climate change research. However, the IPCC explicitly states that the choice between different GWP timeframes is a value judgement that has no scientific basis (IPCC, 2013, p. 711). Some researchers argue that both the 20-year and 100-year GWPs are important for thoroughly understanding the relative climate change impacts of different GHGs (Ocko, 2017). The 100-year time frame is insufficient because it undervalues the warming of short lived gases like methane and suggests continued warming influence after the gas has been removed from the atmosphere. Conversely, the 20-year time frame is insufficient because it does not fully consider warming impacts after 20 years (Ocko, 2017).

The threat of climate tipping elements provides further justification for utilizing the 20-year GWP. Tipping elements represent irreversible and abrupt shifts in Earth’s major systems (e.g. seasonal monsoons). These shifts can have drastic consequences on ecological and human systems, causing serious reductions in human welfare (Lenton, 2008; Schellnhuber, 2009). Given that some of these tipping elements may be passed in decadal time scales, utilizing the 20-year GWP is valuable because it provides the most useful information regarding climate change drivers relevant to avoid passing climate tipping points.

Since animal agriculture is the largest source of human-caused methane emissions, producing 44% of global methane emissions (Gerber, 2013), the chosen time-frame for calculating GWP has large impacts on calculating the relative contribution of animal agriculture to climate change. If the FAO revised their finding that animal agriculture is responsible for 14.5% of global GHG emissions by using the 20-year GWP rather than the 100-year GWP to calculate climate forcing, the relative climate change contributions of animal agriculture would be higher.

1.5.2 — Rewilding, Reforesting, and Sequestration

Typically, calculations of land-use change driven emissions related to agriculture, like the FAO report “Tackling Climate Change Through Livestock,” only consider annual emissions (Gerber, 2013). However, a thorough analysis of the long-term climate benefits of shifting to plant-based diets should consider historical land-use emissions, and the subsequent sequestration potential of rewilding, reforestation, and afforestation of abandoned agricultural land. Determining historical land-use driven emissions and future afforestation driven sequestration potential involves a high degree of uncertainty. Nonetheless, it is a useful and necessary exercise.

The IPCC reports that roughly 32%, or 180 GtC (gigaton carbon), of total global GHG emissions from 1750–2011 can be attributed to land-use change (IPCC, 2013, p. 475). In addition, roughly 50% of ice-free land on the globe is dedicated to agriculture (Gerber, 2013). Therefore, a huge portion, if not the majority, of land-use driven GHG emissions are a result of agriculture. A review of the literature found that vegan diets could reduce dietary land-use requirements by 45% compared to typical diets (Aleksandrowicz, 2016). Thus, it is reasonable to assume, even if it is difficult to quantify with a high degree of certainty, that a global transition to plant-based diets would have significant mitigation potential. The literature that explores this issue supports this assumption.

A recent and unique study quantified the current global biomass carbon storage in terrestrial ecosystems and the potential biomass carbon storage in the absence of land-use changes (Erb, 2017). Current vegetation biomass stocks contain 450 petagrams of carbon (PgC), with a maximum range of 536 PgC. In the absence of land-use change, potential biomass stocks could contain 916 PgC, with a minimum range of 771 PgC. This suggests that current land-use has reduced the amount of carbon that could be stored in terrestrial biomass by around 466 PgC, with a minimum difference of at least 235 PgC (Erb, 2017, p. 74). Even this highly conservative estimate reveals significant sequestration potential given that anthropogenic emissions have increased atmospheric carbon by 240 PgC since 1750 (IPCC, 2013, p. 467). Moreover, the researchers found that restoring artificial pastures to 100% carbon storage potential could sequester roughly 108 PgC, and restoring cropland and artificial pastures to just 30% carbon storage potential could sequester roughly 61 PgC (Erb, 2017, Extended Data Table 4). Other research has also found significant sequestration potential. Smith and Rothwell examined historical and future land-use emissions, and utilized an optimistic future climate change scenario that assumed global reforestation throughout the 21st century. They found that 70 PgC are sequestered throughout the 21st century under this scenario (Smith & Rothwell, 2013). For reference, 4 PgC accumulated in the atmosphere annually from 2000–2009 (IPCC, 2013, p. 486).

It’s important to note here that scientists caution against relying on negative emissions technologies (including reforestation and afforestation) for effectively addressing climate change (EASAC, 2018). While reforestation and afforestation have significant potential to sequester carbon dioxide, there remain significant challenges. For instance, carbon sequestration from afforestation may be offset by nitrous oxide emissions if nitrogen fertilizer is used. Moreover, carbon sequestration from reforestation and afforestation is vulnerable in the long run due to changing political priorities and natural forest degradation (e.g. fire) (EASAC, 2018). Nonetheless, transitioning towards plant-based diets likely offers the greatest potential (although also involves significant barriers) to halt current deforestation and land-use degradation, and begin reforesting and rewilding natural areas.

1.6 — Biodiversity Loss

Biodiversity loss is primarily driven by habitat loss and overexploitation (unsustainable rates of hunting, fishing, etc.). Pollution, invasive species and disease, and climate change are secondary, although significant, drivers of biodiversity loss (Brook, 2008; Living Planet Report, 2017; Sala, 2000). Importantly, these drivers of biodiversity loss often have synergistic effects (Brook, 2008). For instance, habitat loss can reduce the ability of species to adjust to climate change as they have more difficulty moving into new regions that support necessary climatic conditions for survival (Living Planet Report, 2017).

As previously noted, animal agriculture is the leading cause of deforestation and land-use change (Aleksandrowicz, 2016; Erb, 2016; Gerber, 2013; Machovina, 2015). Therefore, it is also the leading cause of habitat destruction (Machovina, 2015). In addition, overexploitation is the leading cause of biodiversity loss in marine ecosystems (Living Planet Report, 2016). Furthermore, animal agriculture is a major driver of chemical pollution, and is a leading cause of nitrogen pollution and marine dead zones (Diaz and Rosenberg, 2008; Erisman, 2013). Finally, animal product consumption is one of the primary drivers of climate change, as discussed in detail in section 1.5 of this report (Aleksandrowicz, 2016; Tilman & Clark, 2014). Because consuming animals contributes to all these drivers of biodiversity loss to varying degrees, it is likely the leading cause of biodiversity loss (Machovina, 2015).

PART 2 — VEGANISM AND SUSTAINABILITY

The environmental impacts of animal agriculture reveal that animal product consumption must be significantly reduced to create a sustainable food system. Even though the science tends to provide evidence that fully plant-based diets result in the smallest ecological impact, there is uncertainty regarding how extensively animal product consumption should be reduced. Significant reductions in animal product consumption, rather than total cessation, may be sufficient from an environmental perspective. Given this reality, Part 2 explores the justifications for veganism as opposed to a simple reduction in animal product consumption.

Part 2 begins by analyzing veganism as a standalone social justice philosophy. Next, the definition of sustainability is explored before veganism is examined as a powerful strategy for promoting a sustainable culture. Finally, it is suggested that a complete and morally consistent definition of sustainability should include veganism as a guiding principle.

2.1 — Veganism as a Necessary Social Justice Philosophy

There are moral issues associated with the consumption and general use of animal products. Scholars have attempted to address these issues by proposing various approaches to animal ethics. Most prominent are the utilitarian and deontological philosophies described by Peter Singer (2009) and Tom Regan (1983), respectively. Other animal ethics approaches explore overlapping oppressions, analyzing the intersections between animal ethics, environmental ethics, feminism, anti-racism, anti-capitalism, and various other anti-oppression approaches (Harper, 2010; Kemmerer, 2011). Importantly, these intersectional animal ethics approaches may be supported by deontological or utilitarian philosophies, but expand the analysis beyond nonhuman animals. Because this paper is focused on veganism, the two most prominent deontological animal ethics approaches will be explored briefly in more detail.

While utilitarian approaches are interesting and valuable, they are not strictly vegan since veganism is fundamentally an anti-exploitation philosophy, and is therefore supported by deontological philosophies. However, it is important to note that many utilitarian animal ethics approaches, while not being strictly vegan in an academic sense, are largely vegan in practice. For instance, individuals may eschew consumption and use of all animal products primarily as a strategy for reducing suffering, rather than to respect the fundamental rights of nonhuman animals. Moreover, it is likely that many individuals are influenced by deontological and utilitarian philosophies simultaneously (Tanner, 2008), and may be influenced to boycott animal product consumption both as a strategy for reducing suffering and respecting the rights of nonhuman animals.

According to deontological philosopher Tom Regan, animals that meet the subject-of-a-life criteria, or “individuals who have an experiential welfare” (Regan, 1983, p. 262), have inherent value. If these individuals have inherent value, they are entitled to the respect principle. The respect principle states that as a matter of strict justice, any individual who is a subject-of-a-life must not be treated as having instrumental value, and instead must have their inherent value respected. Deriving from the respect principle, animals are also entitled to the harm principle. The harm principle states animals have a right to not be needlessly harmed, as doing so would violate the animal’s right to be treated as an individual with inherent value (Regan, 1983).

A similar approach to animal ethics was proposed by Anna Charlton and Gary Francione (2015). Instead of the subject-of-a-life criteria, they propose sentience as the criteria for receiving basic rights. They propose that sentience (the ability to subjectively perceive the world and feel pain and pleasure) grants those individuals the right to not be regarded as a commodity or the property of somebody else. If sentient animals must not be treated as property, then all animal use must be abolished (Francione & Charlton, 2015). While these two philosophical approaches to animal ethics have a few differences, they both propose the same lifestyle that respects the rights of nonhuman animals: veganism.

Veganism is defined as “a strict vegetarian who consumes no animal food or dairy products; also: one who abstains from using animal products (as leather)” (Merriam-Webster Dictionary, 2016). While this definition is functionally correct, it doesn’t fully capture the philosophical nature of veganism. For this reason, the definition used by the Vegan Society is preferred. “Veganism is a way of living which seeks to exclude, as far as is possible and practicable, all forms of exploitation of, and cruelty to, animals for food, clothing or any other purpose” (Vegan Society, 2016). In other words, veganism is a philosophy that rejects needless exploitation, violence, and death of nonhuman animals. At this point, it is important to explore the justification for including the word “needless” in this definition.

Making a distinction between needless and necessary exploitation in this context speaks to the definition of veganism which includes the phrase “as far as is possible and practicable.” The use and exploitation of animals is ubiquitous in western society. Even the most dedicated vegans likely contribute to animal exploitation, even if it is unintended or indirect. Moreover, less privileged individuals may experience greater barriers toward avoiding animal exploitation. For example, individuals living within food deserts have reduced access to healthy and affordable food (Beaulac, 2009). Consequently, the word “needless” highlights the reality that completely avoiding contributing to animal exploitation is virtually impossible for a variety of reasons.

From a strictly social justice perspective, the moral philosophy discussed above reveals the need for veganism as opposed to reductions in animal product consumption. Animal product consumption is a sustainability issue, but it is also a social justice issue since it involves sentient animals that are entitled to basic rights. While any reductions in animal product consumption is a positive outcome from a sustainability perspective, only reducing consumption of animal products, rather than total cessation, is problematic from an animal rights perspective. Therefore, veganism is the most effective lifestyle for simultaneously respecting the basic rights of nonhuman animals and addressing the sustainability issues related to animal product consumption.

2.2 — Defining Sustainability

Sustainability is a concept with conflicting definitions, largely influenced by the philosophical perspectives of those who use the term. Likely the most common framework that describes sustainability is the triangle of sustainability, sometimes referred to as the Three Pillars of Sustainability (Vinnari & Vinnari, 2013, p. 372–373). This framework suggests that sustainability can be cultivated by giving equal consideration to the social, environmental, and economic aspects at different scales, from individuals to global society. While this framework is useful, it fails to capture the fullest meaning of sustainability. For this reason, a more radical notion of sustainability is required. Therefore, sustainability can be considered “the possibility that human and other life will flourish on the planet forever” (Ehrenfeld, 2009).

What exactly constitutes “flourishing” for humans is not easy to determine, although Ehrenfeld provides further explanation. According to Ehrenfeld, producing the possibility of flourishing requires addressing the three domains of sustainability simultaneously: the human, the natural, and the ethical. The human refers to the need for humans to live free, authentic lives. In this context, authentic means being free from social norms and exploitation so you can make choices that bring true satisfaction. The natural refers to the fact that humans are a part of, rather than separate from, nature. Moreover, it refers to the need for humans to preserve the life support systems that support all life, and derive joy and inspiration from nature. Finally, the ethical refers to the need for humans to take responsibility for our actions (Ehrenfeld, 2009). Ehrenfeld only briefly explores what constitutes flourishing for other life on this planet (2009, p. 55–57).

Sustainability has been a largely anthropocentric concept, focusing on human well-being and society (Vinnari & Vinnari, 2013, p. 374). While some environmentalists believe ecosystems have inherent moral value, and most support the protection of ecosystems and biodiversity due to the instrumental value they provide human societies, few are concerned with the moral value of individual nonhuman animals (Kemmerer, 2015).

2.3 — A Required Culture Shift

Currently, western cultures, and the dominant global socio-economic system, are driven by a culture that propagates unsustainability. Given the unsustainable trajectory of modern society, sustainability will require broad and deep cultural shifts (Ehrenfeld, 2009). In fact, sustainability researchers acknowledge that sustainability transitions require long-term shifts in the values, norms, and ethics of the dominant culture (Vinnari & Vinnari, 2013). Due to the significant overlap between the values, beliefs, and norms that underpin both veganism and sustainability, veganism has the potential to support and hasten the culture shift necessary for cultivating sustainability.

There are various values that tend to underpin pro-environmental behavior. These may include self-transcendent values characterized by universalism, benevolence, altruism toward humans, and altruism toward the biosphere and other species, self-interest, both in the form of material benefits and intrinsic satisfaction, and ecocentrism, the belief that ecosystems have inherent value (Nordlund & Garvill, 2002; Stern, 1999; Young, 2000). Research suggests vegetarianism is also underpinned by a strong emphasis on altruism and the harm/care moral dimension, and a rejection of traditional values such as the benefits of social hierarchy and the authority/respect dimension (Allen, 2000; Allen & Baines, 2002; Backer & Hudders, 2015; Kalof et al., 1999). More specifically, it is likely that veganism involves strong altruism toward other species.

A novel paradigm has emerged since at least the 1970s called the New Ecological Paradigm (NEP) (Dunlap, 2000). The NEP is characterized by pro-ecological beliefs related to humanity’s right to dominate nature, the reality of limits to growth for human civilization, and the ability of humans to disrupt the balance of nature. Importantly, individuals who receive a high score on the NEP scale, indicating a pro-ecological orientation, are more likely to accept and adopt broad pro-environmental beliefs and attitudes (Dunlap, 2000). Moreover, acceptance of the New Ecological Paradigm (NEP) has a positive relationship with support for the environmental movement and the adoption of pro-environmental behavior (Stern, 1999, p. 85). Belief about human right to dominate nature is particularly relevant to veganism. As previously noted, vegetarians tend to reject the benefits of social hierarchy and authoritarianism (Allen, 2000; Backer & Hudders, 2015). In fact, one study found that individuals who reported an opposition to social hierarchy and human dominance over nature were found to have less favorable attitudes toward meat, and increased their consumption of fruits and vegetables (Allen and Baines, 2002).

Finally, research suggests that personal norms, moral norms, and feelings of guilt are important, although indirect, predictors of pro-environmental behavior (Bamberg & Möser, 2007; Nordlund & Garvill, 2002; Stern, 1999). Thus, promoting veganism may increase the likelihood of an individual eliminating animal product consumption as they recruit greater levels of guilt and an additional moral norm, in this case animal rights, that supports the desired behavior change. On the other hand, social norms and perceived behavioral control also predict pro-environmental behavior (Bamberg & Möser, 2007). Given that veganism is a deviant behavior and has various barriers, the additional behavioral motivation provided by feelings of guilt and an animal rights-based moral norm may be somewhat counteracted.

There is considerable overlap between the values, beliefs, and norms that underpin both vegetarianism and pro-environmental behavior. Unfortunately, the available literature has not investigated a causal relationship indicating that the adoption of veganism supports the adoption of sustainable cultural characteristics. It is possible that individuals who adopt vegetarianism have already accepted the values, beliefs, and norms that drive pro-environmental behavior. However, multiple studies have found that environmental motivations were rarely cited as an initial reason for adopting vegetarianism, but vegetarians recruited environmental motivations after initial adoption (Fox & Ward, 2008; Rozin et al., 1997). Therefore, it is possible that the adoption of veganism contributes to a cultural shift conducive for cultivating a sustainable society. It is also important to note that many of the relationships presented here between veganism and sustainability likely apply to other meat-reduction behaviors such as vegetarianism and flexitarianism, although to a lesser degree. Due to the radical nature of veganism, it likely has a larger impact on the cultural changes required to cultivate sustainability.

2.4 — Flourishing for Nonhuman Animals

If sustainability is characterized by the possibility of all life, not just humans, having the ability to flourish on this planet (Ehrenfeld, 2009), a conversation about what constitutes flourishing for nonhuman animals is required. Moreover, this discussion should consider both wild animals and domesticated animals.

First, both human and sentient nonhuman animal flourishing should include the ability to live free and authentic lives. What constitutes “free and authentic” is of course different for nonhuman animals. For instance, nonhuman animals are not influenced by social norms to the same degree humans are, if at all. However, nonhuman animals can be, and routinely are, exploited for human purposes. Sentient nonhuman animals have inherent interest in their lives, mirroring the human condition in this regard. Therefore, breeding and using them for human purposes against their will constitutes exploitation, just like it would in the case of humans. Considering wild animals, environmental degradation (through the destruction of habitat), live capture, and killing of “pest” species reduces or eliminates their ability to live authentic lives in their natural habitat. Domesticated animals, by definition, are bred for human purposes. If they are bred for human purposes (i.e. exploited), they do not have the ability to live authentic lives.

Reconnecting with the ethical sphere, and taking responsibility for our actions, is a necessary component for human flourishing. This suggests we must consider our ethical obligations to nonhuman animals as well as humans. Humans have ethical obligations to moral patients, or individuals that do not have the ability to make moral decisions but can be impacted by decisions made by moral agents. Moral patients may include human infants, humans with severe mental disabilities, and the majority of nonhuman animals (Regan, 1983).

Therefore, a sustainable culture should allow all sentient beings the possibility to live authentic lives, and must take seriously the ethical responsibility humans owe toward nonhuman animals. If human exploitation of nonhuman animals removes their ability to live authentic lives, and therefore removes their ability to flourish, truly cultivating sustainability requires a rejection of nonhuman animal exploitation. In practice, this suggests that veganism (i.e. rejecting needless exploitation of nonhuman animals) is a necessary component of sustainability.

2.5 — Overview of Intersections Between Veganism and Sustainability

While the science analyzing the intersections between veganism and sustainability is slim to nonexistent, an interdisciplinary approach utilizing moral philosophy, the natural sciences, and the social sciences can begin to shed light on the sustainability benefits of veganism. First, there is a clear scientific consensus that significantly reducing animal product consumption is one of the primary strategies for creating sustainable food systems and addressing most of the primary global environmental issues. In fact, consuming animal products is one of the most ecologically destructive human behaviors. Furthermore, it is likely that the adoption of veganism promotes a cultural shift that positively influences the cultivation of a sustainable society. In addition to these benefits, the adoption of veganism is desired from a social justice perspective. Avoiding the needless exploitation of nonhuman animals is required to respect their basic rights. Finally, a morally consistent sustainability approach should strive to create the possibility of flourishing for all life. In the case of sentient nonhuman animals, this means adopting veganism as a philosophy that rejects the needless exploitation of nonhuman animals.

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