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Animal Agriculture's significant role in the degradation of the environment

A review of the available scientific literature

Humanity, as a species, is widely accepted to be in a league of its own regarding the ability to think critically, logically and with imagination. However, as a species, many of us have forgotten, choose to ignore, or simply are unaware of our place within a functioning planet-scale ecosystem that requires good environmental health. Environmental degradation is driven by many factors but the role of dietary choices is often overlooked.


With the human population on Earth racing towards 8 billion people, the pressures that humanity places on the environment are becoming increasingly exacerbated. The importance of the environment is unparalleled; food, oxygen, microbiomes and chemical interactions, these all require the presence of a healthy, functioning environment. Scientific literature suggests that a healthy environment contributes to an increase in positive human-health outcomes (Gentry-Shields & Bartram, 2014, p.306; Oguntoke & Adeyemi, 2017, pp.538; Waring et al. 2018pp.64), benefits to global and local economies long-term (Gonzalez-Redin et al. 2018, p.2), as well as reducing damage brought on by stochastic events such as floods, cyclones and drought (Das & Crepin, 2015, p.98; Narayan et al. 2016). As numerous studies indicate that humanity has begun a mass extinction event (McCallum, 2015, pp.2497; Ceballos et al. 2017), as well as triggering climate tipping points and subsequent feedback (IPCC, 2018), discourse surrounding necessary change has commenced. Reducing meat and dairy consumption is one of the most significant actions an individual can make to mitigate their impact on the environment. This article will explore discourse surrounding land use, climate change, water scarcity and waste as a means of highlighting the role of environmental degradation as a direct result of animal agriculture.

The sheer prevalence of livestock is the initial concern. Mammalian biomass on earth is now 60% livestock, predominately cattle and pigs; whereas for birds, 70% of all avian biomass is poultry (Bar-On et al. 2018, pp.6506). This dominance of animals bred for consumption over wildlife is contributing to environmental destruction. Machovina (2015, pp.419) emphasizes that the leading cause of habitat loss globally is in fact livestock and feedstock production, both of which are increasing as demand and population expand. The leading cause of species and biodiversity loss around the world is the removal of habitat (Portugal et al. 2016 pp.44-54; Venter et al. 2016); without habitat, flora and fauna struggle to survive beyond the next generation. Unfortunately, animal agriculture requires a vast amount of land to produce the same nutritional output as a plant-based diet; a study of almost 40,000 farms suggests that agricultural land use would be 75% less if (where applicable) humanity adopted a plant-based diet (Poore & Nemecek, 2018, pp.987–992). Livestock uses just shy of 80% of global agricultural land (60% of this is for beef alone), and yet produces only 20% of humanities calorie consumption (Alexander et al. 2018). Therefore, the unnecessarily large amount of land wasted begins to highlight the role of animal agriculture and environmental degradation. When this is compounded with greenhouse gas emissions and water usage, the personal justifications required to consume meat and dairy become even more laborious.

This issue of meat and dairy consumption is an ever-increasing matter, since 1960 the human population has doubled, meat consumption has tripled and egg and dairy have increased four-fold (Blattner, 2020). With climate change being an immensely serious issue that humanity needs to solve rapidly, reducing greenhouse gas emissions is vital. Animal agriculture is responsible for 18 percent of all global greenhouse gas emissions (Grant, 2017, pp.744; Jankielsohn, 2015, pp.1145), again, beef is the worst offender. Therefore, as the population continues to increase and meat consumption continues to increase even faster, solving the climate crisis becomes an increasingly difficult task. A literature review of 21 peer reviewed articles undertaken by Gonzalez-Garcia et al. (2018, pp.77–94) explains that western diets rich in meat, especially ruminant meat, have low nutritional scores and high carbon footprints, whereas Mediterranean and Indian diets had higher nutrients and a lower carbon footprint. International bodies such as the UN have tasked themselves with advocating policy implementation and individual actions to mitigate the climate crisis. Coupled with a transition from fossil fuels to renewable energy, reducing meat consumption is highlighted as just as pivotal by the UN (Blattner, 2020). A recent literature review into the comparison of emissions in diets found that a plant-based diet reduced an individual’s dietary greenhouse gas emissions by ~50% (Fresan & Sabete, 2019). This notion of emissions is compounded when the land use is further critiqued, for example, if the aforementioned land used for animal agriculture was available, the carbon sequestration potential through reforestation projects would be immense!

The discourse surrounding climate justice issues is equally as imperative within this discussion. Alexander et al. (2016) states that to consume the quantity of meat consumed in the USA or Australia, it is ecologically impossible for the entire world to do the same. These nations have particularly high carbon footprints, expressing 16.24 tonnes and 16.9 tonnes per capita respectively (Richie & Roser 2017), as well as eating over 115kg of meat on average each year (Richie & Roser 2017). Whereas countries like Bangladesh produce only 0.53 tonnes per capita and eat under 5kg of meat per capita (Richie & Roser, 2017). This notion of climate justice is highly tangible as it is developing nations that have lesser responsibility for the climate crisis but will suffer more. For example, Davis et al (2018) have produced models that indicate rising sea levels will displace millions in Bangladesh by the end of the century. Additionally, Bangladesh will experience an increase in tropical cyclone frequency and strength, and a surge in mosquito and water-borne diseases as a result of the rising sea levels. Under-developed nations such as Bangladesh will both experience the effects of climate at a higher rate and simultaneously be less climate-resilient than the countries with greater responsibility. As the discourse of environmental degradation is explored, the notion of inter-connectedness becomes increasingly apparent; climate change among other environmental concerns exponentially increase other issues, such as water insecurity.

Without water, life as we know it simply cannot exist. Unfortunately, fresh water is a finite resource and is very precious to functioning environments and human diets. Therefore, to ensure a healthy functioning environment, humanity must mitigate its impact on water consumption and water quality health. An animal’s body is comprised of 60-70% water, and biochemical and physiological process require and use water (Legesse et al. 2017, pp.2003). The additional steps required to produce and consume animal products, plus the need to eat plant-feed themselves, are more water-intensive than a plant-based diet. A study in California, USA, stated that a diet with an average consumption of animal products required an additional 10,252 litres per week more than that of a nutritionally adequate diet with less animal products (Harold et al. 2015). Additional research comparing a standard western diet and a Mediterranean diet found that by consuming a Mediterranean diet which is comprised of less meat, particulary red meat, could reduce an individual’s water footprint by a massive 1,629 litres per day (Blas, Garrido & Barbara, 2016). In countries with drier climates such as Australia, consuming red meat and dairy is putting harmful, unnecessary stress on the fragility of an increasingly difficult climate. To visualise this concept of water required, 1kg of beans requires 2.5m3 of fresh water whereas 1kg of beef requires 20.2m3 of water (Fresan & Sabete, 2019, pp.380). An even better mode of contrasting is protein content, which again, beef requires 10 times more water than beans to produce the same level of protein content (Fresan & Sabete, 2019, pp.380). Climate change is expected to increase water scarcity globally, leading to conflict between those effected (Gosling & Arnell, 2016, pp.371-385). Once more, humanities compounding pressures placed on the environment benefit from a reduction of meat and dairy consumption. These pressures continue to build when the inefficiency of current food practices is considered.

One third of all food produced is wasted (Schanes et al., 2018, pp.978–991). This unnecessary wastage was examined further by Shepon (2018, pp.3804–3809) who explains that, factoring in nutritional and protein content, juxtaposing plant and beef expresses a twenty-fold increase in food waste opportunity, negatively in favour of beef. The aforementioned food waste revolves around food not eaten, however, genuine waste products such as excrement are considerable pollutants and a focus of concern too. 2500 cows produce the same amount of excrement as 411,000 humans in the USA (Baroni, Denise & Silvia, 2018, pp.160). This waste infiltrates the finite freshwater environments, causing eutrophication among other degradational effects. As powerful as nature is, the fragility correlating to human impacts is beginning to put pressure on our lifestyles that require a healthy, functioning environment.

The detrimental impacts of animal agriculture put forward within this argument draw on science, logic and ethical considerations. The impending climate emergency being by far the biggest concern results in the need to mitigate individual emissions juxtaposed with industrial changes is beyond necessary. Land use concerns correlating to the likes of the unfolding mass extinction event suggest that we need to ensure we act on reducing our land use size and impacts. With potential conflict arising from water scarcity, as well as continually compounding impacts on the environment from said water scarcity, again, humanity must reduce its impact. The ethical implications of consuming animal products which very clearly have highly detrimental impacts on the environment are profound. This argument could absolutely be expanded upon and examine the factors not included in this paper, however, the authors believes the aforementioned arguments are more than enough for an individual to reduce their meat and dairy consumption; are taste and pleasure truly more important than the environment which allowed your very existence?

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