Course:CONS200/2021/Environmental Footprint of Cow's Milk vs. Plant-based Milks

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Cow's milk has been a part of human nutrition for more than 8000 years[1]. However, with emerging issues like lactose intolerance, dairy allergies and increasing concerns about the environmental impact of cow’s milk, there has been a growing demand for plant-based milk alternatives. With plant-based milks being able to come from a variety of plants they have been increasing in popularity over the last several years. For individuals who want to make a change in their lifestyle whether it be for growing concerns over climate change, choosing not to consume animal products or for those who cannot consume dairy products, plant-based milks have become a welcome alternative.

History of Cow's Milk & Plant-based Milks

Image of cow's milk versus plant-based milks.

Following the advent of agriculture, cow's milk has been a well-known beverage choice around the world. It is a staple in the human diet and is considered an influential dietary recommendation worldwide[1]. Additionally, milk is an excellent source of vitamins and minerals and provides valuable nutrients such as calcium, proteins, fats and carbohydrates[2]. These nutrients play an important role in supporting healthy development. For instance, calcium helps strengthen bones and teeth, as well as benefiting muscle movement and decreasing rates of osteoporosis into adulthood[3]. Potassium is key for a healthy human heart, decreasing blood pressure, as well as the risk of further heart diseases[3]. Cow's milk also contains all the essential amino acids needed for body functioning[3]. In addition to these benefits, cow's milk acts as a protective factor against some types of cancers, such as colorectal, bladder, gastric and breast cancers[4]. Although nutrient-rich cow's milk can benefit humans of all ages, it is particularly supportive for children whose growing bodies require high levels of these nutrients in order to maintain healthy development[3]. Even one study has shown that ingesting cow's products like milk can actually reduce the risk of child obesity[4], which is a growing issue in western society today. While there has been some research that has brought up concerns about the levels of saturated fats and cholesterol in cow's milk, which can increase risk of heart disease[3], most research studies have found very few unfavourable health effects of milk consumption[4].

Unfortunately, cow's milk is not a healthy and suitable option for all individuals. Lactose intolerance, the inability to break down lactase, is common in human populations, impacting a predicted 65% of the general population[3]. Therefore, lactose intolerant individuals must find other dietary sources to provide the valuable nutrients found in cow's milk. Nevertheless, one of the major drawbacks of cow's milk is the fact that dairy production has significant negative environmental impacts such as high water usage, requires larger amounts of land for production[5], production of other byproducts[6] and is a leading contributor of greenhouse gas emissions[7]. These problems have caused society to rethink whether their choices in cow's milk consumption is sustainable or plant-based milk is a better alternative.

With the growing number of dairy allergies, lactose intolerance and environmental concerns, plant-based milks have been identified as a more healthy, environmentally-friendly option and have been gaining huge popularity in western society[8]. The first plant-based milk was soy milk which originated in China about 2000 years ago[9]. Plant-based milks have become popular in part because they are advertised as "sustainable" and it best fits consumers' ideal lifestyle[8]. The most popular motives behind plant-based milk consumption occur due to many individuals partaking in a more "plant-focused" lifestyle and a variety of ethical, social, environmental and economic reasons influence them too[1]. Furthermore, many studies show animal welfare, particularly for vegans, is the key basis to pursuing a more plant-focused lifestyle and mindset as it focuses more on wellness and health[1]. Hence, consumption is mainly for its dietary values and ability to be fundamentally better and more eco-friendly compared to cow's milk.

Economically the success of plant-based milks has been growing at a rapid pace and with a wide range of milk options. The three main plant-based milks categories are grains, nuts and legumes. The plant-based milks that can be found in supermarkets worldwide are made from either almond, coconut, hazelnut, soy, hemp, rice, oat, walnut, pea, flax, sesame and pistachio[3][9].Though it must be noted that these plant-based milks do not provide enough nutrition to people's diets and the usage of new and advanced non-thermal processing technologies such as ultra-high pressure homogenization, ultra-high temperature treatment and pulsed electric field processing have been used to combat the problem[9]. These technological advancements have further been able to increase plant-based milks shelf-life, nutritional completeness, sensory acceptability and emulsion stability[9]. Yet, these plant-based milk products have become an inexpensive alternative and trend in developing countries that lack the supply of cow's milk[9]. Ultimately with society's growing preferences of plant-based milks, they could eventually replace the cow's products which will result in a huge reduction of environmental impacts. However, plant-based milks come with major environmental concerns of high water and land usage, and high overall carbon footprint.

Environmental Impacts of Cow's Milk

Comparison of the different environmental impacts of milk.

As mentioned previously, despite the health benefits, cow's milk production has a number of adverse effects on the environment, which has led to a growing demand for other more sustainable alternatives, such as plant-based milks. Some of the major environmental issues in cow's milk production is carbon dioxide and other greenhouse gas emissions, and land and water usage. Due to the amount of resources required to sustain dairy cows, and the byproducts that result from the production of the milk itself, dairy farms emit a large amount of greenhouse gases. In fact, in 2007, it was estimated that international dairy production was responsible for 4% of all human-made greenhouse gas emissions[10]. Therefore, emissions from cow's milk production is disproportionately large, considering the amount of anthropocentric activities that contribute to greenhouse gas emissions. For instance, the United States, which is responsible for 12% of the world's cow milk production, has a dairy industry that is responsible for 2% of the country's total greenhouse gas emissions[5]. According to Poore & Nemecek, one litre of cow's milk will produce 3.3kg of CO2 equivalent emissions, a much higher emission rate than plant-based alternatives[7]. In addition, the resources to produce one litre of cow's milk will use over 8.9m2 of land, and use 600 L of water to produce[7]. The growing demand for plant-based milks can be understood because the environmental impact of cow's milk is so much larger than milk alternatives such as soy milk, which only produces 1.0kg of CO2 equivalent emissions and requires considerably less water and land to produce[7].

Dairy cows require a large amount of resources to sustain them, such as large amounts of land for feed and grazing, which contributes to deforestation and high levels of water use[7]. Unfortunately, this contributes to the negative environmental impact of cow's milk, as it has been estimated that deforestation practices are responsible for 10% of carbon dioxide emissions globally[10], making land use an area of concern for the future of sustainable dairy production. Furthermore, an unsustainable amount of money and land is used to support dairy cows in food production as about 25% of the total cow's milk production costs in the European Union go towards paying for feed[11]. Additionally, in the United States, 9% of all the land set aside for growth of crops is used for feed production for just dairy cows[5]. Another example from a study of a dairy farm in Sweden found that 200 hectares of land were used for feed production for 100 cows over three years[12]. When this statistic is compared to the only 50 hectares used for the pasture and grazing[12], we can see that a large amount of land usage for dairy production is merely to sustain the cattle population, illustrating how using animals for food production can be particularly unsustainable in that they require a large amount of land to produce feed. Land use is becoming an increasing area of environmental concern as it is a limited resource that is also being threatened by numerous factors, such as growing world populations, increasing pressure for conservation areas, and other forms of food production, so efficient land usage for dairy production is an important area for future research[10]. Water usage has also become a notable issue in the dairy industry, as, in the United States, an estimated 144 gallons of water are needed to produce only 1 gallon of milk[5]. Once again on the subject of feed production, of these 144 gallons, nearly 135 gallons go toward producing feed for dairy cows[5]. Large amounts of electricity are also required to sustain dairy milk production. The Government of Ontario website shows that Ontario dairy farms will use 800-1400 kilowatts per hour per cow per year, on average[13]. The source also shows that levels of energy consumption for milk systems and milk cooling make up 44% of the average energy use for Ontario dairy farms[13].

Dairy cows and dairy production also have various other byproducts that impact both local and global environments. Dairy cows produce methane, which is then released into the atmosphere. Unfortunately, methane makes up half of all greenhouse gas emissions caused by dairy production in Western nations and contributes to global climate change[6], having further negative effects on the environment such as rising sea levels. Another byproduct of dairy farming is manure, which has been shown to have a negative impact on water bodies nearby farms[14]. Each day, a dairy cow produces about 17 gallons of manure and urine[5]. Manure has multiple negative environmental effects including releasing greenhouse gases into the atmosphere, and being a pollutant to both water, air, and surrounding environments[5]. Specifically, manure spreading releases nitrogen and phosphorus emissions into the environment which has effects on water quality for humans and animals, especially if impacting commonly-used water basins[6].

Luckily, some changes are being made around the world to create more sustainable dairy production practices and to lower greenhouse gas emissions. For example, in the United Kingdom, there is a movement to more accurately measure the carbon footprint of cow's milk in order to limit carbon emissions[15]. This project will help guide dairy production to become more sustainable in the future, involving limiting cow's methane emissions[15]. Moreover, a study in Denmark predicted that if future Danish cow's milk production prioritizes minimizing greenhouse gas emissions and energy-usage, there will be no economic trade-off[16], which points to the possibility of introducing more sustainable dairy production practices in the future. Another study in Sweden has explored the environmental benefit of sourcing feed for cattle locally rather than importing it from other European nations, which could lower greenhouse gas emissions in cow's milk production[17].

It is important to note that although cow's milk is one of the products with the highest greenhouse gas emissions[12], it is just one product contributing to unsustainable food production practices. Overall, food production makes up 26% of anthropogenic or human-produced greenhouse gas emissions[7]. Much of the greenhouse gas emissions caused by food production is due to deforestation for agricultural land[7]. Agricultural land for food systems covers 37.4% of the ice or desert-free land on Earth, which takes a significant portion of land away from native plant and animal species in order to make space for feed and grazing for domesticated animals[7]. Due to these issues, plant-based milk alternatives have begun to gain popularity as a more sustainable option for the environment.

Environmental Impacts of Plant-based Milks

Environmental impacts of plant-based milks are more predominant than most think, each with their own specific downfall. With the large variety of plant-based milks that have grown beyond the traditional soy milk to include other plant-based alternatives like almond, oat, coconut, pea, hemp, and other grains, seeds, nuts, and legumes comes different environmental impacts for each. Every milk alternative has a downside, some more than others. When producing plant-based alternatives three of the major environmental concerns are water use, land use and carbon footprint.

According to research, plant-based milks are overall a better consumer and agricultural decision in terms of milk production when considering environmental impacts. However, there are a few circumstances in which some plant-based milks are just as costly for the environment as cow’s milk. A popular example is the revolutionary almond milk, first popularized for its potential to change the face of how dairy products impact the planet and offer a “greener” way of living, is actually the plant-based milk that requires the most water to produce. Almonds require 15 gallons of water per 16 almonds to produce[18]. Due to this almond farming has been placed in areas with large wetlands[18]. One popular almond farming location is the San Joaquin Valley in California. Due to the increase of almond production upon their wetlands , the valley has experienced drastic groundwater depletion causing the land to sink and damage the underground water tables, consequently closing off the city’s freshwater supply[18]. The second most environmentally unfriendly plant-based milk is rice milk. Rice production, similar to almond production, requires the flooding of grasslands, therefore is the milk product that requires the third largest amount of water[7]. Rice milk, in comparison to the other plant-based milk options, emits the largest quantities of CO2 and other greenhouse gas emissions (GHGs) such as methane; emitted during the flooding process of rice fields.

Soy milk is one of the very first plant-based milks ever produced, and an option highly preferred in Asian countries both as a beverage and in their cuisine. This plant-based milk uses the least amount of water in comparison to almond, rice, oat and cow’s milk[7]. It also produces less than a third of the GHGs than cow’s milk and requires substantially less land use[7]. Though environmentally beneficial and efficient in these ways, soy milk is also one of the leading culprits for the Amazon’s deforestation. Soy production within the Amazon was initially produced to use in farming as cattle, sheep and salmon food[19]. However, due to soy production for its milk, more and more land within the Amazon is being deforested to accommodate the rising interest and demand for soy milk[19].  

Besides the well-known plant-milks; almond, soy, rice and oat, there are many other varieties being produced today and available at your local coffee shop and store. Such varieties include hemp, coconut, hazelnut, walnut, pea, flax, cashew, sesame and pistachio milk[20]. These options are lower in popularity yet are still being consumed by the general public. Though lower in popularity, these milks can arguably be better for the environment as they are produced in lower quantities and require less land and water use overall[7]. One instance of a mostly environmentally-friendly and highly popularized option is coconut milk. Very common in south eastern cooking, it is one of the plant-based milks that require the least land use[21]. As they have a large yield of milk per coconut tree, they require both little maintenance to grow and to harvest without having to deforest the area and natural landform says Sujatha Bergen[21]. Though highly efficient and eco-friendly in its production, it falls as a detriment to the environment due to the amount of CO2 emitted whilst being exported all across the globe from the hotter and more humid climates the coconut trees thrive in[21]. The rise of the climate movement and an interest in plant-based lifestyles within society, whether it be for health or personal preferences, has provoked an increase in the production of these plant-based milks. Plant and cow farming are two very different methods of production; resulting in two particularly different systems of side effects. Cow farming impacts the environment through a system that goes from the grass and through the cow whilst in plant production side effects are to plots of land used for production themselves. This can include eutrophication, deforestation and acidification of nearby water sources as the upkeep of plant agriculture is much more straining on the land itself[7].

Despite these plant-based milks having substantial negative impacts on the environment, they are still exponentially better for the environment than cow’s milk. The greatest difference is seen in land use. Cow’s milk requires 3.9 times more land (m2) per litre of milk than oat, rice, almond and soy milk combined[7]. Cow’s milk also produces up to 3 times more GHGs than any single plant-based milk, giving cow’s milk the highest global warming potential[7][22]. In comparison to plant-based milks cow’s milk produces between 1.14 to 2.5 kilograms of CO2 per litre of milk whilst a plant-based alternative produces between 0.42 to 0.75 kilograms of CO2 per litre of milk[7]. Thus, any progress made in the transition from cows milk to plant-based alternatives is going to be beneficial for the environment in the long term.  

Conclusion

Cow’s milk has been a staple of the human diet for thousands of years. Due to its high nutritional value, cow’s milk can support healthy development and offer many valuable health benefits. Nevertheless, with rising numbers of lactose intolerance, dairy allergies, and increasing concern for the environment, plant-based milks have emerged as a popular alternative. When compared to plant-based alternatives, cow’s milk emits a significantly larger amount of greenhouse gases and requires more land and water to produce. Moreover, dairy cows also require a large number of resources to sustain them and produce various byproducts that can be damaging to both local and global environments, such as methane and manure. Although changes are being made to create more sustainable practices in the cow milk industry, plant-based milks have been identified as being a more environmentally-friendly alternative. The level of sustainability varies between different types of plant-based milks. Even though almond milk is more sustainable than cow’s milk, it uses a greater amount of water throughout the process of growing and production than other plant-based milks such as oat or soy milk. Every milk option, whether it be cow’s milk or plant-based milk has an environmental impact, but it is ultimately up to the individual consumer to select the option that works best for them based on their nutritional needs and personal values.

References

  1. ↑ 1.0 1.1 1.2 1.3 Haas, R.; Schnepps, A.; Pichler, A.; Meixner, O. (2019). "Cow milk versus plant-based milk substitutes: A comparison of product image and motivational structure of consumption". Sustainability (Basel, Switzerland). 11(18): 5046 – via MDPI.
  2. ↑ Paul, A. A.; Kumar, S.; Kumar, V.; Sharma, R. (2020;2019;). "Milk analog: Plant based alternatives to conventional milk, production, potential and health concerns". Critical Reviews in Food Science and Nutrition. 60(18): 3005–3023 – via Taylor & Francis Online. Check date values in: |date= (help)CS1 maint: extra punctuation (link)
  3. ↑ 3.0 3.1 3.2 3.3 3.4 3.5 3.6 Ware, M. (2020, March 16). "What to know about milk". Medical News Today. Check date values in: |date= (help)
  4. ↑ 4.0 4.1 4.2 Kongerslev Thorning, T.; Raben, A.; Tholstrup, T.; Soedamah-Muthu, S.S.; Givens, I.; Astrup, A. (2016). "Milk and dairy products: good or bad for human health? An assessment of the totality of scientific evidence". Food & Nutrition Research. 60 – via Taylor & Francis Online.
  5. ↑ 5.0 5.1 5.2 5.3 5.4 5.5 5.6 "Milk's impact on the environment". World Wildlife Fund. Winter 2019. Retrieved April 1, 2021.
  6. ↑ 6.0 6.1 6.2 Arvidsson Segerkvist, K.; Hansson, H.; Sonesson, U.; Gunnarsson, S. (2020). "Research on environmental, economic, and social sustainability in dairy farming: A systematic mapping of current literature". Sustainability. 12: 5502 – via ProQuest.
  7. ↑ 7.00 7.01 7.02 7.03 7.04 7.05 7.06 7.07 7.08 7.09 7.10 7.11 7.12 7.13 7.14 7.15 Poore, J.; Nemecek, T. (2018). "Reducing food's environmental impacts through producers and consumers". Science (American Association for the Advancement of Science). 360: 987–992 – via SpringerLink.
  8. ↑ 8.0 8.1 Clay, N.; Sexton, A. E.; Garnett, T.; Lorimer, J. (2020). "Palatable disruption: the politics of plant milk". Agriculture and human values. 37(4): 945–962 – via AAAS.
  9. ↑ 9.0 9.1 9.2 9.3 9.4 Sethi, S.; Tyagi, S. K.; Anurag, R. K. (2016). "Plant-based milk alternatives an emerging segment of functional beverages: A review". Journal of Food Science and Technology. 53(9): 3408–3423 – via SpringerLink.
  10. ↑ 10.0 10.1 10.2 Flysjö, A.; Cederberg, C.; Henriksson, M.; Ledgard, S. (2012). "The interaction between milk and beef production and emissions from land use change – critical considerations in life cycle assessment and carbon footprint studies of milk". Journal of Cleaner Production. 28: 134–142 – via ScienceDirect.
  11. ↑ Sakari, H. L. (2015). "Evaluating adaptation and the production development of Finnish agriculture in climate and global change". Agricultural and Food Science. 24: 219–234 – via DOAJ.
  12. ↑ 12.0 12.1 12.2 Röös, E.; Patel, M.; Spångberg, J. (2016). "Producing oat drink or cow's milk on a swedish farm — environmental impacts considering the service of grazing, the opportunity cost of land and the demand for beef and protein". Agricultural Systems. 142: 23–32 – via ScienceDirect.
  13. ↑ 13.0 13.1 "Using less energy on dairy farms". Ontario.ca. September 2010. Retrieved April 3, 2021.
  14. ↑ Paudel, K.; Gauthier, W.; Westra, J.; Hall, L. (2005). "Dairy programs to reduce manure-related environmental problems: The case of the louisiana milkshed". Journal of Environmental Systems. 31: 367–383.
  15. ↑ 15.0 15.1 "Dairy industry gets pat on the back for green initiative". The Guardian. 7 August 2009. Retrieved April 3, 2021.
  16. ↑ Oudshoorn, F. W.; Sørensen, C. A. G.; de Boer, I. I. J. M. (2011). "Economic and environmental evaluation of three goal-vision based scenarios for organic dairy farming in denmark". Agricultural Systems. 104: 315–325 – via ScienceDirect.
  17. ↑ Sasu-Boakye, Y.; Cederberg, C.; Wirsenius, S. (2014). "Localising livestock protein feed production and the impact on land use and greenhouse gas emissions". Animal. 8: 1339–1348 – via ScienceDirect.
  18. ↑ 18.0 18.1 18.2 Fleischer, D. (2018, January 1). "Almond Milk is Taking a Toll on the Environment". UCSF Sustainability. Check date values in: |date=, |archive-date= (help)
  19. ↑ 19.0 19.1 Fraanje, W.; Garnett, T. (2020, January 20). "Soy: food, feed, and land use change". Table. Check date values in: |date= (help)
  20. ↑ Hooke, A. (2020, July 9). "17 Different Plant Milks You Need To Try". Switch4Good. Check date values in: |date= (help)
  21. ↑ 21.0 21.1 21.2 Krietsch, B. (2020, January 7). "The Best Milk Alternatives For Your Health (And The Environment)". The Huffington Post. Contribution by: Sujatha Bergen. Check date values in: |date= (help)
  22. ↑ Marinova, D.; Bogueva, D. (2020, October 14). "Which 'Milk' Is Better For The Environment? The Answer May Surprise You". Science Alert. Check date values in: |date= (help)


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