There are many reasons to go vegan: some people do it for ethical considerations, some do it for their health, and some people do it for the environment. However, with respect to the environment, there is sometimes confusion about the effects of veganism on the climate and the planet in general. Rumors circulate that diet has no effect on the environment, and even that a meat-based diet is better for the environment. Our diet as a species has a remarkable impact on our planet, and in some ways has been very harmful, due to the meat we consume. Because of the systematic ways in which we get our food, we can cause major shifts in the planet’s ecosystem and climate by how we decide to use the land and ocean we dominate, whether that be through the continuation of current practices, or a shift to a more sustainable diet. To be clear, a plant-based diet is better for the environment than a meat-based diet, and a vegan diet is best.
It might not be obvious to everyone how the effects of an animal-inclusive diet harm our future, but in a time when unprecedented heat waves are sweeping the Pacific Northwest of the United States, it becomes increasingly important to understand.
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How does a meat-inclusive diet harm the environment?
Animal agriculture accounts for 14.5-18% of greenhouse gas emissions (4). That’s more than all the transportation exhausts worldwide, including the transportation exhausts spent on food (4). Transportation accounts for less than 10% of greenhouse gas emissions related to food (4). In just the European Union, 83% of greenhouse gases contributed by the human diet are from animal products (4). With our ever-expanding population as a species and our technological prowess, our diet has a huge impact on the future of the world we live in.
It is clear that our current farming practices used for raising animals for food are energy-intensive and contribute significantly to global warming. Although it is not readily apparent how raising animals for slaughter harms the environment, studies have shown that our food system produces harmful greenhouse gases in order to support the growth of animals from which we harvest meat and dairy.
For example, a 2014 study by Peter Scarborough et al. was conducted on the greenhouse gas emissions produced by different diets, measured in kgCO2e (greenhouse gas in kg weighted by how much global warming one kg can cause over the course of a century). The study included 55,504 participants aged 20-79, divided into 29,589 meat eaters, 8,123 pescetarians, 15,751 vegetarians, and 2,041 vegans (7). It was found that a high meat content diet produced 7.19 kgCO2e per day, a medium meat content diet produced 5.63 kgCO2e per day, a low meat diet produced 4.67 kgCO2e per day, a pescetarian diet produced 3.91 kgCO2e per day, a vegetarian diet produced 3.81 kgCO2e per day, and a vegan diet produced 2.89 kgCO2e per day (7).
According to these results, a diet high in meat content produces more than twice the greenhouse gas emissions of a vegan diet. Even the low meat diet produces over one and a half times the climate-changing gases than a vegan diet. This means that you can more than double your own positive effect on our future as a species just by going vegan.
Where do the emissions of these diets come from?
Most of the greenhouse gas emissions caused by a meat-based diet are not directly from the diet itself; they are caused by the system that produces the food. A huge part of it is the effect of the immense amount of agriculture needed to sustain diets for the animals raised for human consumption. Our food supply chain causes 13.7 billion tons of carbon dioxide equivalents, accounting for over a quarter of anthropogenic greenhouse gas emissions (5).
These emissions are caused by the methane produced by animal feed growth and by animals’ digestive systems. Far more detrimental to the climate of the planet than carbon dioxide, methane has a kgCO2e measurement of 25, compared to the much lesser but still powerful kgCO2e value of 1 for carbon dioxide.
How efficient is a meat-inclusive diet?
More than a quarter of Earth’s iceless land is being used for the grazing of farmed animals, accounting for 83% of all agricultural land, and in the UK alone, that number is over 85%, accounting for almost all of the total land there (4). Compare that to the US, where 45% of its 3,797 square miles is used for agriculture (4). About 91% of that land is used for animal agriculture, leaving only 4% of the total land in the United States for growing food for a plant-based diet for humans (4). On top of that, about half of that 45% of land used for raising cow meat alone (4).
One would think that this meat must comprise most of the American diet, then. However, it only accounts for 3% of the total consumed Calories (4). Greenhouse gas emissions from beef can be 105 kg of carbon dioxide equivalents per 100 g of protein (5). The United States has a per capita meat consumption rate much greater than the rest of the world, by over three times. If Americans were to collectively change their diet to a more plant-based option, they could reduce food-based greenhouse gas emissions by 73% (5). (That’s a lot of power coming from one place, but it doesn’t mean that non-Americans’ diets don’t matter!)
The United States is not the only place where making cow patties is a pastime to be reckoned with. In Brazil, cattle ranching is responsible for 80% of the loss of the Brazilian Amazon, and fires in the Amazon are heavily correlated by the vicinity to cattle ranching (4). These forests are incredibly important to the ecosystem of the planet at large, sequestering carbon and providing oxygen for all of us animals to filter through our systems and keep us alive, as well as keeping the global climate at a sustainable level. The ranching, then, if curtailed, could help save the Amazon.
Given that information, we can see that we are looking at a vast imbalance when it comes to the benefits versus the costs of raising animals for the purpose of human consumption. According to Earthling Ed, “animal farming is the leading cause of rainforest deforestation, the single largest driver of habitat loss in general” (2021).
In a broad view, 24,000 of 28,000, or over 85%, of species at risk of extinction are in that endangered zone as a direct result of animal farming practices (4). This is because animal farming takes up so much land that it must encroach on and destroy thriving habitats.
People usually think of veganism when they hear “soy,” which is a common dairy alternative and the main ingredient in tofu, a popular source of protein for vegetarians and vegans alike (4). However, only 6% of whole soybeans produced is used for human consumption, and 75% is given to farmed animals for them to eat (4). What if the land used to produce soybeans for animal feed was used for something more efficient and less hazardous to our planet?
The current meat-based food system in the U.S. is not efficient in feeding the people who depend on it. A 2019 study by Harwatt, H., and Hayek, M.N. found that if using the same amount of land that is currently used for animal feed were to be used for growing food for a healthy plant-based diet, it could feed 350 million more people—more than the population of the entire nation (4).
The UK is in a similar situation. If one-third of the UK land currently used for producing animal feed were used to produce vegetation for people, more than 60 million extra people could be fed by that land (4). When taking into account the amount of environmental damage caused by animal farming, it becomes even more worth it to change our practices and embrace veganism.
If the worldwide land used for agricultural animal feed were used for a human plant-based diet instead, we would only need 25% of the current farmland currently in use (5). This is “the equivalent size of China, Australia, the US, and the entire European Union combined.” (4). Imagine the expanse of homogenous ruminant habitat being converted to the biodiverse ecosystems these areas could be. This process could remove a significant portion of carbon dioxide from our atmosphere and save our future (4).
Right now, our global population is approaching 8 billion and is projected to reach 10 billion within three decades (4). The meat industry in the UK alone has increased its supply from 69.2 kg/person/year to 84.2 kg/person/year between 1969 and 2013 (7) Meat in the human diet is increasing, and it is expected that animal-based foods will increase by 70%, and the environmentally hazardous ruminant-based diet, in particular, will increase by 88%, requiring even more land to support this lifestyle (593 million hectares, to be more precise) (4). In anticipation of this trend continuing, we need to seriously slow our meat intake.
What about seafood?
We can see that a diet of terrestrial animals harms the planet and makes it less habitable for us, but what about a diet that relies on sea animals for protein? Unfortunately, science supports the idea that a worldwide human diet dependent on sea life is not sustainable. Where we used to see the ocean as a mysteriously unending supply of food, things have changed. Although the ocean is still mysterious to us, as we have explored less than 10% of it (3), we are seeing a trend of depletion in the life we can take from it.
It is estimated that “food production creates ~32% of global terrestrial acidification and ~78% of eutrophication” (5). Acidification is an increase in the number of hydrogen atoms in the environment and can cause a once-thriving place to be uninhabitable to the life that evolved to dwell there. Eutrophication means an excess of nutrients that ultimately cause the ceasing of life for animals in a marine environment. What this means for us as humans is a reduction in food productivity and marine biodiversity (5).
How is marine food productivity decreased through… well, food productivity?
There are two main types of ocean fishing: bottom trawling and longline fishing. Bottom trawling is when a large net is dragged along the bottom of the ocean to pick up whatever is there. Usually, there is a target species, but the net knows nothing about this and picks up everything in its path. Bottom-trawling disrupts the marine ecosystem by catching unintended species indiscriminately and disrupting the seafloor. This disturbance mixes already present pollutants in with the plankton, resulting in disruptions such as algal blooms and dead zones caused by deficient oxygen (2).
Longline fishing also catches indiscriminate species, including animals we don’t normally eat, such as “whales, dolphins, seals, sea lions and turtles” (3). About 650,000 of these animals die each year just because they got caught by a hooked line that can span from 50-100 kilometers (3). In addition, about 50 million sharks are caught by accident each year (3). These senseless deaths are disturbing in and of themselves, but they also have far-reaching consequences on the ocean’s biodiversity.
Biodiversity isn’t just for fun. Biodiversity in marine systems is positively correlated with the ability to withstand disturbances (8). This means that with enough biodiversity, a small change in the environment is no big deal; it will bounce back. However, with little biodiversity, a small change could easily set off an immense and unpredictable chain of events, like a trail of dominoes or a house of cards.
A 2006 study found that vital processes such as “primary and secondary productivity, resource use, nutrient cycling, and ecosystem stability” were greatly decreased by a lack of marine biodiversity (8). The difference is stark, with up to an 80% swing in productivity based on biodiversity (8). This means that the entire system of the ocean is changing based on our appetite for crustaceans and fish, to the point that we may not be able to sustain it. The same study found that if trends continue, we will have out-fished the ocean by the middle of the century. When we consider that 50-80% of the planet’s life is in the ocean, this news is alarming (3). It could have disastrous effects on not only our diets if we don’t slow down, but it could also have unpredictable effects on the carbon dioxide exchange between the ocean and the atmosphere. The ocean may seem separate from us, but this illusion is dispelled by the fact that about 50-85% of the oxygen we breathe is created by marine phytoplankton (3).
When marine biodiversity changes, there can be disastrous unintended consequences (8). Unfortunately, with our current fishing habits, we are creating an unpredictable whirlwind of change in an environment we haven’t even fully explored. We have damaged “estuaries, coral reefs, and [entire fish communities]” (8). Studies by Danielsen et al. and Adger et al. show that because so many people live and are moving to coastal areas, it is vital to maintain control over the nearby marine environment (8).
Consider also, for a moment, that fishing has also contributed to the garbage patch in the north Pacific—a brig of floating refuse—by adding 86% of the macroplastics there in the form of fishing nets (3).
What about fish farming?
Even though industrial fishing is harmful, farmed fish are not the answer. This is because most of the fish we are familiar with have a high trophic level. This means that they eat other fish that eat other fish, etc… Because so many fish that humans eat rely on other fish for their nutrient intake, farmed fish still must be fed with ocean wildlife taken with nets and hooks via trawling and longline fishing (3). When buying fish, there is no escaping industrial fishing. Fish farming also produces an insane amount of waste; some farms produce the same amount as half a million people (3).
With all this in mind, it can still seem unnatural to maintain a vegan diet. Questions arise about protein sources and nutrition in general. People often assume that a vegan diet cannot be healthy.
Veganism can be better for you
It is worth noting that there are, in fact, health benefits to a plant-based diet. A smattering of studies by Davey et al. (2003), Ferdowsian and Barnard (2009), and Berkow and Barnard (2006) showed that a lower BMI and healthier lipid content is associated with lower animal product intake (7). This could be due to the balance of nutrition found in a plant-based diet: The authors of this study note that as animal consumption decreased among the participants, so did the consumption of saturated fat, while the consumption of fiber, fruit, and vegetables increased (7). It is established by Crow et al., Huang et al., and Key et al. that better heart health is associated with lower animal product intake (7).
From this, we see that our future, both individually and collectively, is dependent on the dietary choices we make today.
How can we help?
Unfortunately, a lot of damage has been done to the planet already. It is not a secret that we have been depleting Earth’s resources for over a century without much forethought to the consequences, despite innumerable warnings from scientists. We are currently seeing the effects of that with the melting of ancient ice, and feeling the effects with unprecedented heatwaves. What we are experiencing now is expected to be just a taste of what will come within this century, and the survival of our current habitats where we live is in question. What we need now is not hemming, hawing, debating, or half-effort. Simply reducing our consumption of meat will not be enough at this point. It is time for the species that has let its glut go unchecked for far too long to go full vegan.
References & Footnotes
- “Biodiversity is a finite resource, and we are going to end up with nothing left … if nothing changes,” said Boris Worm, an assistant professor of marine conservation biology at Dalhousie University in Halifax, Canada (Roach, 2006).[↩]
- Chestney, N. (2012, September 5). Trawling could harm oceans like ploughing land: scientists. Reuters. https://www.reuters.com/article/us-trawling-oceans-idUSBRE88416820120905 [↩]
- Earthling Ed. (2020, August 30). What eating fish does to the planet, explained [Video]. YouTube. https://www.youtube.com/watch?v=UfZ4vCx3pF4[↩]
- Earthling Ed. (2021, May 28). Veganism could save the planet. Here’s why. [Video]. YouTube. https://www.youtube.com/watch?v=QnrtRaM28cY[↩]
- Poore, J., & Nemecek, T. (2018). Reducing food’s environmental impacts through producers and consumers. Science, 360(6392), 987–992. https://doi.org/10.1126/science.aaq0216[↩]
- Roach, J. (2006, November 2). Seafood may be gone by 2048, study says. National Geographic. https://www.nationalgeographic.com/animals/article/seafood-biodiversity[↩]
- Scarborough, P., Appleby, P.N., Mizdrak, A., Briggs, A.D.M., Travis, R.C., Bradbury, K.E., & Key, T.J. Dietary greenhouse gas emissions of meat-eaters, fish-eaters, vegetarians and vegans in the UK. (2014) Climatic Change. 125, 179-192. https://doi.org/10.1007/s10584-014-1169-1[↩]
- Worm, B., Barbier, E.B., Beaumont, N., Duffy, J.E., Folke, C., Halpern, B.S., Jackson, J.B.C., Lotze, H.K., Micheli, F., Palumbi, S.R., Sala, E., Selkoe, K.A., Stachowic, J.J., Watson, R. (2006). Impacts of biodiversity loss on ocean ecosystem services. Science, 314(5800), 787–790. https://doi.org/10.1126/science.1132294[↩]