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Photo: Jo-Anne McArthur / Eyes On Animals / We Animals Media
The issue of climate change grows more pressing with every passing day. Repeatedly, research and reports have shown that dietary change is a necessary part of altering our current trajectory toward climate catastrophe. That is, even if emissions are halved by 2030 and net zero carbon emissions achieved by 2050, “but dietary patterns see no shifts, the world will fail to meet the Paris Agreement.” Given meat’s caloric inefficiency, and the profound impact that production of meat of all types has on the climate, there is an extremely clear case for us to switch to eating more plant-based foods and transition away from consuming meat.
The impact of meat production on the climate is massive. Conservatively, our food systems are responsible for one-third of human-caused greenhouse gas emissions. The factory farms that we use to house the billions of animals who are slaughtered every year for meat have a disproportionate representation (57 percent) within this total. In addition, these facilities contribute heavily to pollution, deforestation, and the use of land and water. The United Nations Intergovernmental Panel on Climate Change (IPCC) recognizes a sustainable diet as one that is high in grains, nuts, seeds, fruits, vegetables, and pulses, and low in animal-sourced foods such as meat.1
Beef—specifically beef that is the product of herds of cattle raised solely for meat—is undoubtedly one of the most resource-intensive foods. For every kilogram of beef produced, 99.48 kilograms of carbon dioxide is released into the atmosphere. Just 1,000 calories worth of beef requires 119.49 square meters of land and 994 liters of fresh water. When you consider these numbers in light of the 2.81 million individual cattle slaughtered for beef in just one month in the United States alone—equating to over 1 billion kilograms of meat—the staggering environmental impacts of the beef industry become clear. Because of dramatic statistics like these, you may have heard that just cutting out beef is enough to adequately reduce the negative environmental impacts of our diets, but unfortunately this is far from the truth.
Though beef may have the biggest impact of all animal-derived foods on climate change and environmental degradation, other animal-derived foods aren’t far behind. Lamb and mutton require the most land to produce a single kilogram of meat: 369.81 square meters. Seafood requires the most fresh water use per 1,000 calories of meat, with farmed shrimp requiring 3,413 liters of water and farmed fish needing 2,062 liters of fresh water. Even when we consider the categories where beef ranks first, the impact of other meat products is clear. For example, in terms of greenhouse gas emissions per kilogram of meat, lamb and mutton are second (39.72 kilograms), followed by beef from dairy cattle (33.3 kilograms) and shrimp (26.87 kilograms).
In all of these comparisons, one animal raised for meat is notably absent: chickens. Though chickens do not rank first when it comes to land or fresh water use, and may even compare well to meats as terrible for the climate and environment as those listed above, chicken production is nevertheless still a much larger contributor to climate change than most plant-based foods. Chicken meat, like other types of meat, is calorically inefficient. Chickens require nine times more calories than their meat contains. It would be far more efficient to dedicate the land and resources used for raising chickens to instead grow food for direct human consumption.
Perhaps one of the areas of gravest concern when it comes to chickens’ impact on climate change and the environment relates to feces and urine. Chicken droppings are rich in nutrients such as phosphorus, nitrogen, and potassium. Chickens are raised in such immense numbers that manure makes its way into waterways near chicken farms, polluting river environments and worsening dangerous algal blooms. A report from the Environmental Integrity Project found that in the Chesapeake Bay, 24 million pounds of nitrogen pollution entered the water from the surrounding poultry farms in 2018 alone. Just maintaining chicken farming at its current scale is detrimental to the environment, and a dangerous driver of climate change.
Policymakers, farmers, academics, and activists alike acknowledge that meat production contributes significantly to climate change; this is the driving force behind proposed management strategies such as methane digesters and feeding seaweed to cattle. However, these solutions are not enough in the face of the impending threat of climate change.
According to the Food and Agriculture Organization of the United Nations (FAO), animal agriculture is responsible for 8.1 gigatons of carbon dioxide-equivalent greenhouse gas emissions. Of this total, only 26 percent actually consists of carbon dioxide; about half is methane and another quarter nitrous oxide, both more potent greenhouse gasses than carbon dioxide, though they remain in the atmosphere for a far shorter period. According to the FAO, roughly 40 percent of these emissions can be tied back to the production of feed for the animals on factory farms.
Methane is the most prominent greenhouse gas emission from animal agriculture, comprising half of the 8.1 gigatons released every year by the industry. Two of the largest producers of methane within animal agriculture are the digestive systems of the animals themselves and manure.
Deforestation is a significant cause of climate change. Meat production, and especially cattle ranching, has proven one of the largest drivers of deforestation . In the Brazilian Amazon rainforest alone, 65 percent of all deforestation can be tied back to cattle ranching.2
Shifting away from diets heavy in meat and focusing on eating plant-based foods such as legumes, fruits, vegetables, and whole grains was suggested as a policy solution for climate change by a recent IPCC report. Per the report, making this shift could free up several million square kilometers of land and provide technical mitigation potential of up to 8 gigatons of carbon dioxide-equivalent greenhouse gas emissions every year.
The United States has committed to cutting greenhouse gas emissions by 50 to 52 percent from 2005 levels by 2030, as well as to reduce emissions from agriculture in general and methane in particular. Shifting what we eat will be a necessary step toward achieving this goal. With the animal agriculture industry producing 32 percent of human-caused methane emissions every year, it is no surprise that one of the key steps to reduce methane emissions is shifting away from diets that are high in animal-derived products.3
Yes. Given the massive toll of animal agriculture on the environment and climate, reducing and preferably eliminating meat from our diets is a necessary step to prevent the continued warming of the planet. Repeatedly, reports from international governing bodies including the IPCC and the Climate and Clean Air Coalition have recognized the need for dietary change as a means to combat the environmental toll of animal agriculture.
In lower-income countries, animal agriculture often plays an important role in the lives and economies of many households. Animals provide a means of securing food and often also provide a source of income. However, these households are not the ones that are driving climate change, and their diets do not tend to contain a large amount of meat. Rather, higher-income countries such as those in Europe and North America are primarily responsible for the overproduction and overconsumption of meat. For example, the average U.S. citizen consumes 215 pounds of meat every year.
In higher-income countries, those most at risk from a mass shift away from meat and toward plant-based alternatives are farmers who grow crops for animal feed, farmers who raise pigs, chickens, and other birds, and the employees of meatpacking plants. Yet the demand for plant protein sources to be used in alternative proteins—including legumes, peas, oats, and mung beans—is likely to increase significantly as part of such a transition, providing some opportunity for farmers to switch to new products. If the transition is well-managed there is the potential for other opportunities to grow in rural communities alongside the plant-based economy.4 Some farmers have already begun away from raising animals toward cultivating mushrooms or other crops.
The farmers, companies, and academics invested in continued beef production have come up with a variety of ways to reduce the environmental impacts of the industry. However, none of the tactics that they have suggested are enough to sufficiently lessen the industry’s contribution to climate change.
Methane digesters are one supposed method for reducing the amount of methane released into the atmosphere. The digesters, however, can only be used on certain types of factory farms, and digesters at best capture only the additional methane created by the adoption of factory farm practices in the first place. Further, methane digesters are very expensive and lack economic viability—when they are used, they tend to be subsidized.
Another proposed solution is regenerative agriculture, in which crops and cattle are raised together on the same land. While this method of farming is an improvement over monocrop systems of production, promising to reduce greenhouse gas emissions from agriculture and allow improved soils to store more carbon, regenerative methods also require more than double the amount of land of other farming systems, and the extra carbon stored does not fully offset the emissions caused by farming animals.
In recent years, leading climate change researchers and policy recommendations have highlighted the importance of moving away from consuming meat and instead eating more plant-based foods. Despite this, the global beef industry is projected to increase in size within just the next year, and the U.S. market for chicken, turkey, and pork is expected to expand. We cannot reach the goals set in the Paris Agreement unless dietary patterns evolve. The research is clear; one of the most effective things institutions and individuals can do to mitigate climate change is to shift our food choices.
P.R. Shukla, J. Skea, R. Slade, R. van Diemen, E. Haughey, J. Malley, M. Pathak, J. Portugal Pereira (eds.), Technical Summary, 2019, Climate Change and Land: an IPCC special report on climate change, desertification, land degradation, sustainable land management, food security, and greenhouse gas fluxes in terrestrial ecosystems, in press November 14, 2022, p. 58, https://www.ipcc.ch/site/assets/uploads/sites/4/2020/07/03_Technical-Summary-TS_V2.pdf.
F. Recanati, et al., “Global Meat Consumption Trends and Local Deforestation in Madra de Dios: Assessing Land Use Changes and Other Environmental Impacts,” Procedia Engineering 118 (2015): 630–638, https://doi.org/10.1016/j.proeng.2015.08.496.
A. R. Ravishankara et al., “Global Methane Assessment” (Climate and Clean Air Coalition, UNEP, 2021), https://www.ccacoalition.org/sites/default/files/resources/2021_Global-Methane_Assessment_full_0.pdf.
Peter Newton and Daniel Blaustein-Rejto, “Social and Economic Opportunities and Challenges of Plant-Based and Cultured Meat for Rural Producers in the US,” Frontiers in Sustainable Food Systems 28 (January, 2021), https://doi.org/10.3389/fsufs.2021.624270.