The plant-based milk industry has expanded dramatically in recent years due to increases in the popularity of vegan milk options, which are usually made from plants like almonds, soybeans, and oats. While dairy milk sales are declining at a rate of 3% each year, sales of plant-based milk have grown 6% in just the past year, and made up 13% of the entire milk industry in 2019. The environmental impacts of cow and plant-based milk certainly have stark differences: on average, producing one glass of dairy milk costs the planet 3 times the greenhouse gas emissions, more than 10 times the land use, and 20 times the amount of water than producing one glass of oat milk. But for the extra environmentally conscious consumers, another important decision is the choice between different vegan milk options.
Comparing emissions, land use, and water use can provide a general idea of the environmental impacts of various milk alternatives, as shown in the following BBC graphic:
Though all alternatives are substantially less carbon and resource intensive than dairy milk, the statistics indicate disparity between the vegan options themselves.
Almond milk, generally made by soaking almonds in water and grinding them to create a creamy white liquid, is currently the most readily available vegan milk in grocery stores, coffee shops, and restaurants across the United States, with sales growing at a rate of 250% in the last 5 years. Although the production of almond milk emits slightly less greenhouse gas than some of its vegan competitors such as soy and oat, the production of almonds is very water-intensive: it takes five liters of water to grow one single almond, which adds up to 74 liters of water to make one glass of almond milk, an amount of water greater than the average kiddy pool. High water consumption for almond production can worsen existing environmental concerns, as 99% of the United States’ almonds, and 80% of the world’s almonds, are grown in the state of California, which is experiencing its most intense drought on record. A recent U.S. Geological Survey found that the Central Valley Aquifer, which stretches under the Sacramento and San Joaquin valleys, is rapidly depleting, the ground above it sinking at a rate of half an inch each month due to overpumping of the groundwater to provide water for agriculture. Almonds require such tremendous amounts of water that they contribute directly to this depletion of groundwater, which puts Americans at risk for food security because the United States relies so heavily on produce grown in this region. So, while almond milk may be popular and produce less greenhouse gas emissions than its alternatives, concerns over water use can make it a less attractive option when deciding which plant-based milk to purchase.
Soy milk, a high-protein vegan milk made from soybeans, was the very first vegan milk alternative in the world and still represents most of the global market share of plant-based milk. In comparison to almond milk, milk made from soybeans requires much less water and about the same amount of land. However, emissions from soy milk are higher than both oat and almond milk, at around 0.2kg of CO2 emitted to produce one 200mL glass of soy milk. Although its land use requirements are statistically similar to those of other plant-based milk options, a deeper analysis reveals that land use for soy milk is more complicated than a simple statistic. The Amazon and Cerrado regions of Brazil have experienced massive deforestation events in order to make way for soybean plantations. Between 2006 and 2017, 220,000 square kilometers of native Amazon and Cerrado vegetation were cleared, and the Cerrado region alone now uses up to 16 million hectares of its land to grow soybeans. In addition to deforestation having its own drastic effects on the global carbon budget due to reduced uptake of CO2 by vegetation, the majority of soy produced in Brazil is for export. Transportation of soybeans around the world via the ocean, land, and air contributes heavily to the emissions associated with the production of soy milk and increases the carbon footprint of the soybeans. 85% of all soybeans are used to feed animals and produce oil, so the problem lies in those industries as well. Nevertheless, the association of soybeans with deforestation and transportation emissions are critical to consider when making a decision about plant-based milk.
Does this mean oat milk, popular for its creamy texture, low sugar content, and richness in fiber, is the best option for the consumer who is concerned about their environmental impact? Not necessarily. Though oats require 6 times less water than almonds do, oat milk costs the planet more land and emissions than almond milk. South Dakota, North Dakota, and Wisconsin produce the most oats in the United States, which are mostly used to produce oatmeal and oat flour. The good thing about oats is that, unlike soybeans and almonds, oats are mainly grown in areas where it is reasonable to do so: in temperate, fertile areas known for high agricultural productivity, such as the American Great Plains and the other major oat-producing countries of the world—Russia, Canada, Finland, and Poland. Even though the majority of the world’s oats are used for animal feed, research suggests oat production is on the decline globally, with growers in the midwestern United States struggling to find markets to sell their oats. American farmers, especially in Corn Belt states like Iowa, want to break the cycle of only growing corn and soybeans by growing oats and other grains like alfalfa, which are more sustainable for the soil and water. Time will tell if the market for oats will become more accessible because, although it seems like the best choice environmentally, growth in oat milk sales has plateaued.
Finally, it is important to keep in mind that all manufacturers behave differently. For instance, Oatly, a Swedish oat milk brand, received backlash in late 2020 over its ties to a controversial private equity firm called Blackstone Group, which is associated with deforestation of the Amazon rainforest in order to build highways that facilitate the exportation of soybeans. Instances like this make decisions complicated. If the consumer wants to limit the water use associated with producing their milk, almond milk might not be the best option for them. If another consumer cares deeply about the Amazon and Cerrado rainforests in Brazil, they may have to say no to soy milk. The decision can be based on care for the environment, personal values, taste preference, and even simply the abundance of plant-based milk at one’s local supermarket. But one thing will remain certain: vegan milk is always better for the environment than dairy milk, and a little purchase can go a long way.
Asher, C. (2019, April 3). Brazil soy trade linked to widespread deforestation, carbon emissions. Retrieved March 1, 2021, from https://news.mongabay.com/2019/04/brazil-soy-trade-linked-to-widespread-deforestation-carbon-emissions/
Boxall, B. (2015, March 18). Overpumping of Central valley groundwater creating a crisis, experts say. Retrieved March 1, 2021, from https://www.latimes.com/local/california/la-me-groundwater-20150318-story.html#page=1
Eller, D. (2017, October 5). Iowa has the world’s largest cereal plant, but state’s farmers lack market for oats. Retrieved March 1, 2021, from https://www.desmoinesregister.com/story/money/agriculture/2017/10/05/iowa-has-worlds-largest-cereal-plant-but-states-farmers-lack-market-oats/690998001/
Guilbourg, C. and Briggs, H. (2019, February 22). Climate change: Which vegan milk is best? Retrieved March 1, 2021, from https://www.bbc.com/news/science-environment-46654042
Helmore, E. (2020, September 1). Activists sour on Oatly vegan milk after stake sold to Trump-linked Blackstone. Retrieved March 1, 2021, from https://www.theguardian.com/food/2020/sep/01/oatly-vegan-milk-sale-blackstone
Park, A. and Lurie, J. (2014, February 24). It Takes How Much Water to Grow an Almond?! Retrieved March 1, 2021, from https://www.motherjones.com/environment/2014/02/wheres-californias-water-going/
Plant Based Foods Association. (2019, July 12). U.S. Plant-Based Retail Market Worth $4.5 Billion, Growing at 5X Total Food Sales. Retrieved March 1, 2021, from https://plantbasedfoods.org/2019-data-plant-based-market/
Zwer, P.K. (2004). Oats in the Encyclopedia of Grain Science. Retrieved March 1, 2021, from https://doi.org/10.1016/B0-12-765490-9/00113-0