Looking for Ways to Fight Climate Change? Consider Your Diet

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Whether we want to or not, it’s time to address an uncomfortable truth: Climate change is happening right before our eyes, and won’t be going anywhere unless we as humans collectively take action to reverse it. Another uncomfortable truth? Something as simple as changing our diets away from meat and animal products would have a profound impact on the health of the environment, yet the vast majority of the population is unwilling to accept that and adjust their lifestyles. This is evidenced by an upward trend of meat consumption in recent decades, with projections by the FAO of a global yearly consumption of nearly 100 lbs of meat and 210 lbs of dairy per person by the year 2030.

In reality, the meat industry emits more greenhouse gases (GHGs) than the global transportation sector combined, totaling 15-18% of all global emissions. Beyond GHGs, animal agriculture is directly linked to soil and water pollution, along with a significant loss of biodiversity worldwide. Compared with a plant-based diet, animal-based diets require 2.5-5.0x the energy inputs, 2-3x water consumption, 13x the fertilizer, and 1.4x the pesticide use per calorie produced. Perhaps the most shocking, livestock production accounts for 70% of all agricultural land and 30% of the land surface of the planet, with 26% of terrestrial Earth occupied by grazing and areas dedicated to feed crop production amounting to 33% of total arable land.

If you’re looking for meaningful ways to be a part of the fight against climate change, adjusting your diet for the well-being of the planet is a great place to start. Below, I’ll highlight major areas of environmental concern that can be significantly improved by adopting a plant-based diet.

Waterway Pollution

When concentrated animal feeding operations (CAFOs) were introduced in the late 1900s, livestock farmers were overjoyed to have found a solution to mass-producing meat and dairy while taking up as little land as possible in doing so. By the USDA’s definition, a “CAFO is an AFO [animal feeding operation] with more than 1000 animal units (an animal unit is defined as an animal equivalent of 1000 pounds live weight and equates to 1000 head of beef cattle, 700 dairy cows, 2500 swine weighing more than 55 lbs, 125 thousand broiler chickens, or 82 thousand laying hens or pullets) confined on site for more than 45 days during the year.” An additional qualification for a CAFO cited by the USDA is any animal feeding operation “that discharges manure or wastewater into a natural or man-made ditch, stream or other waterway,” regardless of size.

In the USA in 1966—before CAFOs had dominated the livestock industry—57 million pigs were distributed among 1 million farms. By 2001, those same 57 million pigs could now be raised on 80,000 farms, with over half raised in just 5,000 facilities. With such high concentrations of animals confined to a single farm, it’s no wonder that the resources used and waste created have dire environmental consequences for surrounding areas. In 2016, a report by Environment America revealed that Tyson, one of the largest meat producers in the world, is responsible for dumping 104 million pounds of pollutants into our waterways from 2010 to 2014—more than companies like ExxonMobil and Dow Chemical. A substantial portion of these discharges by Tyson are nitrate compounds, which contribute to algal blooms and dead zones from the Chesapeake Bay to the Gulf of Mexico, while also posing threats to human health and water viability. Tyson’s remaining pollution footprint includes manure from its contract factory farm operations, fertilizer runoff, and waste from its processing plants.

According to the FAO, livestock farming as a whole is likely the largest source of water pollution, contributing to eutrophication, dead zones in our coastal regions, degradation of coral reefs, human health concerns, emergence of antibiotic resistance, and more. Of these outcomes, the major causes of pollution from CAFOs are from animal wastes, antibiotics and hormones, chemicals from tanneries, fertilizers and pesticides used for feed crops, and sediments from eroded pastures. Per the FAO’s report, “In the US, livestock are responsible for an estimated 55% of erosion and sediment, 37% of pesticide use, 50% of antibiotic use, and a third of the loads of nitrogen and phosphorus into freshwater resources.”

Beyond contaminating our waterways, toxic pesticides and fertilizers used to grow feed crops for livestock pose significant health risks to humans including acute poisoning; long-term effects on the immune, reproductive, and nervous systems; and increased cancer risks. This affects not only the workers in CAFO operations, but neighboring communities who depend on freshwater resources infiltrated by livestock farms.

Land + Air Pollution

Speaking of excessive use of toxic fertilizers and pesticides, the industrial agricultural system also poses threats to public health owing to its unsustainable use of resources, waste, and environmental pollution. According to a Cambridge study, as of 1997, animals in the US industrial agriculture system produced a total of approximately 1.4 billion tons of waste, including manure, urine, carcasses, excess feed, and feathers. Though manure can be used on nearby fields as fertilizer in small operations, CAFOs produce far more waste than fields can absorb and levels of phosphorus and nitrogen in the waste quickly exceed what the soil can retain. To mitigate this, industrial farms often store waste in lagoons which they later apply to fields, untreated, in smaller increments. For a better understanding of how much waste we’re talking, Food and Water Watch estimated that the livestock and poultry on the largest factory farms in 2012 produced 369 million tons of manure—almost 13 times more than the 312 million people in the United States.

Another major complication of such high populations of livestock concern the pollutants from their feed and waste. Many feed ingredients used in CAFOs include heavy metals like arsenic, antibiotics, nitrogen, and phosphorus, which pass through the animals into their manure. This manure, in turn, passes these contaminants into the soil along with neighboring waterways connected to their waste lagoons. Manure also contains dust, mold, pathogenic bacteria, and bacterial endotoxins, which can gravely affect the health of workers on CAFOs who come in frequent contact with the material. According to a study in the journal Public Health Nutrition, as many as 30% of CAFO workers suffer from occupational respiratory diseases like acute and chronic asthma. In addition, a University of Iowa study has found that people living near large-scale pig farming operations report higher incidences of “headaches, respiratory problems, eye irritation, nausea, weakness, and chest tightness.” There is also evidence that children of CAFO operators in Iowa have higher rates of asthma than do other farm children. Most likely, these ailments are a result of air polluted with contaminants like ammonia, sulfur dioxide, mold, and dust from CAFOs.

Water Usage

120 liters of water is required to produce a single 200ml glass of cow’s milk ( University of Oxford ).

120 liters of water is required to produce a single 200ml glass of cow’s milk (University of Oxford).

When you think about reducing your water footprint, you might think of reducing your shower time, turning the faucet off while brushing your teeth, and finding more efficient ways to do the dishes. Though these are all valid efforts, one of the most impactful methods of reducing water consumption is by limiting or eliminating animal products like meat and dairy. According to a study in the journal Animal Frontiers, the consumption of animal products contributes to 27% of the water footprint of humanity—largely due to the water needed to produce their feed. The consequences of such extreme water usage dedicated to feed crops span far and wide to include the depletion of aquifers and draining of groundwater tables across the West, leading to concerns of wells drying up indefinitely. In Colorado, for example, alfalfa to feed cows consumes nearly 30% of the state’s water, which is much higher than the share taken by Denver. Similarly, in 1986, irrigated pasture in the state of California used to grow feed for cattle consumed about 5.3 million acre-feet of water—as much as all 27 million people in the state consumed, including water for swimming pools and lawns.

When looking at the numbers, it becomes apparent just how wasteful and resource-intensive the production of meat, dairy, and eggs are compared to plant-based food sources. Scientist Dr. Georg Borgstrom at the 1981 annual meeting of the American Association for the Advancement of Science concluded that it takes 2,500 gallons of water to produce a single pound of beef—a figure still referenced today, with estimates ranging from 442 gallons (purported by the cattle industry) to 8,000 gallons. In a 2018 study by the University of Oxford, it was reported that nearly 120 liters of water is required to produce a single 200ml glass of milk, compared to less than 20 liters required for a glass of oat or soy milk. Numbers like these span across meat, dairy, and egg production, with energy and resource inputs increased dramatically to produce these foods. According to researcher Joseph Poore at the University of Oxford, “Most strikingly, impacts of the lowest-impact animal products typically exceed those of vegetable substitutes, providing new evidence for the importance of dietary change.”

Greenhouse Gases (GHGs)

When climate change is discussed, most often, we hear about the rise of greenhouse gases like CO2 diminishing our ozone layers and threatening ecosystems across the globe as a result. What we don’t hear about as often as a major source of greenhouse gas emissions? Livestock farming. According to a 2015 paper published in Scientific American, the livestock sector accounts for 9% of CO2 emissions, 37% of methane emissions, and 65% of nitrous oxide emissions. It may seem reassuring that CO2 emissions are of the lowest value, but that’s far from the truth. In reality, methane contains 23x the global warming potential of CO2—warming the planet “on steroids” for a decade or two before naturally decaying to CO2. According to a study by Robert Howarth of Cornell, in those short decades, methane warms the planet by 86x as much as CO2 and is >100x greater than CO2 in absorbing heat.

Overall, it has been found that meat-centric meals generate on average 9x higher greenhouse gas emissions than plant-based equivalents, while animal-based products like beef and cheese cause 10-20x the environmental impact. A similar study by the University of Oxford revealed that greenhouse gas emissions from cow’s milk were almost 3x higher than vegan alternatives when comparing emissions, land, and water usage. Ultimately, all high-protein, plant-based foods in the study (tofu, beans, nuts) emitted less greenhouse gases than the lowest-impact animal proteins. As a result, the researchers argue that cutting meat and dairy products from your diet could reduce your carbon footprint from food by almost two-thirds. In line with this estimate, a study published in the journal Energy Policy calculates potential GHG savings of 22% and 26% made by changing from the current UK-average diet to a vegetarian or vegan diet.

Biodiversity Loss

With roughly 30% of the terrestrial surface of the planet dedicated to livestock feed and production, it’s no surprise that this has led to catastrophic consequences for native species in areas cleared for this purpose. Currently, livestock accounts for approximately 20% of the total terrestrial animal biomass, illuminating a startling asymmetry in the balance of animals present on Earth. What’s more concerning, demand for feed crops to sustain these livestock is still growing, resulting in global deforestation and biodiversity threats. As pointed out by the FAO, in addition to deforestation, the livestock sector is one of the leading drivers in “land degradation, pollution, climate change, overfishing, sedimentation of coastal areas and facilitation of invasions by alien species.”

Another overlooked consequence of the expansive livestock production industry is wild animals that are intentionally eradicated due to resource conflicts with pastoralists. While these animals suffer the indirect damage of meat-related deforestation, pollution, and climate change, they are also directly targeted by the meat industry and frequently killed to protect meat-production profits. In an example of these merciless efforts, grass-eating species such as elk, deer, and pronghorn have been relentlessly killed to reserve feed for cattle, while animals like beavers and prairie dogs have been decimated en masse for disrupting the homogenous landscapes laid out by livestock managers. In the same vein, the Center of Biological Diversity points out that a federal agency known as Wildlife Services “shoots, traps, and poisons millions of animals every year, including foxes and bears in National Forests, to make more room for cows and other ranched animals.”

Lastly—but certainly not least—it’s important to consider our oceans and the biodiversity loss concurrently happening there. With current consumption rates by humans, the depletion of fish from our oceans is above the level of population growth, with 57% of global fish stocks now fully exploited. At full exploitation, a population is at or very close to their maximum sustainable production. Even more concerning, we currently have 30% of global fish stocks overexploited and functioning beyond their maximum sustainable production. Altogether, this is contributing to devastating consequences for fish populations and the oceanic ecosystem as a whole.



Whew! That was a lot of information to take in, but here’s the thing: If anyone is going to do something about climate change, it needs to start with us. And when I say “us,” I mean us normal, everyday people who have the power to make profound impacts on the world around us with our consumption habits. By switching to a plant-based diet and eliminating—or at the very least, greatly reducing—animal products from your life, you’re instantly contributing to the healing of our planet and joining the essential fight against climate change.

As environmental researcher Joseph Poore states, “A vegan diet is probably the single biggest way to reduce your impact on planet Earth, not just greenhouse gases, but global acidification, eutrophication, land use and water use.” Hopefully, together, we can make this meaningful change for the better.

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