Plant-Based Milk Alternatives | Environmental Footprints
August 13, 2019 Katharina Kropshofer By Katharina Kropshofer Follow

Plant-Based Milk Alternatives | Environmental Footprints

Many of us already choose plant-based alternatives to dairy products, others might be wondering which option to buy. But how can you know, which one is best for you and the environment?

Just when we think we might have figured it out, the solution often turns out to be a bit trickier than expected: with vegan, plant-based milks, one might–literally–trust their gut and go for the best-tasting alternative (I’m team oat milk!). Yet, if the reason for your choice of plant-based alternatives is driven by environmental concerns, the sustainability differences between the available options is significant.

Joseph Poore is an environmental scientist at the University of Oxford. Together with his colleague Thomas Nemecek, an agricultural scientist at Swiss Institute Agroscope, he produced one of the biggest studies comparing environmental impact of agricultural products. To do that, they compiled data from 3,000 studies for about 40 different products.1

Sustainable Diets

Even though some of the studies’ messages are surprising and complex, one message comes across very clearly: eating less or no animal products is the single biggest way to avoid impact on the environment.

You’ve likely heard this before, but why? The problem lies not only between high CO2 emissions, vast water consumption and flatulent cows (meaning, more atmospheric methane), but also in its poor land use. Livestock only provides 18% of the calories we need, yet it takes up 83% of our worldwide farmland. Additionally, all animal products–even if they are produced with the smallest environmental impact–lead to higher levels of CO2 emissions than plant-based products.

Sustainability of dairy milk

Let’s take a look at cow milk. In comparison, the environmental effects of one liter ranks worse than any plant-based alternative, no matter which aspect you choose to look at. Three times as many greenhouse gases are emitted compared to the production of soy, rice, oat or almond milk alternatives. Looking at land use, cow milk is doing eight times worse. And when it comes to the usage of water, results seem even more dramatic: 120L of water are needed to produce 1L of milk. 

But which plant-based alternatives are more sustainable?

If you think that all milk alternatives are equally sustainable, I might have to disappoint you. Joseph Poore took a closer look and compared four plant-based milk alternatives,2 and we added extra information on another crowd favourite: coconut ‘milk’. Here is a quick summary of the environmental pros and cons of the five most common milk alternatives:

1. Almond

Looking at almond ‘milk’, the factor of water plays a big role. With 371L of water needed to produce 1L of almond ‘milk’, this milk alternative ranks far behind rice, soy or oat ‘milk’. Since its almonds are often grown in arid areas like California, which are already suffering from water scarcity, almond production can lead to environmental problems. But when we take a look at greenhouse gas emissions and land use, almond ‘milk’ actually ranks better than its plant cousins.

2. Soy

For many, soy ‘milk’ is the first stop when looking for milk alternatives. In contrast to almond ‘milk’, it has other strengths and pitfalls: we can see the best results in terms of water usage, and its land use is also comparatively lower in impact. When it comes to greenhouse gas emissions, however, it falls behind oat and almond ‘milk’ with about 0.7kg of CO2 equivalents emitted for every liter. And here is something else to factor in: international soy farming has a devastating impact on the rainforest, especially in the Amazon. Since soybeans also grow well in many European countries, a look at the label of origin can be useful.

3. Rice

Poore and Nemecek also calculated the effects of rice ‘milk’, a further tasty alternative. It ranks best in land use with less than 0.3 m2 needed to produce 1L. But it is just doing a little bit better than almond ‘milk’ when it comes to water use and produces the most greenhouse gas emissions out of the four plant-based milk alternatives. Rice farming is estimated to account for 2.5% of current anthropogenic warming due to emissions of methane. Massive amounts of nitrous oxide (N2O), another long-lived greenhouse gas, is also emitted during the flooding process of the rice fields. Studies show though, that climate impacts of rice cultivation could be reduced by 90% if we manage to select the most climate-friendly water management regimes.3

4. Oat

Which leads us to the last alternative the two scientist made calculations for: oat ‘milk’. We can see quite a small impact in terms of land and water use. In terms of greenhouse gas emissions, it ranks behind almond ‘milk’ with less than 0.8kg of CO2 equivalents emitted per 1L. Good news also comes from the way oats are grown. In an interview with The Guardian,4 Michaelis Hadjikakou, a researcher from Deakin University (Melbourne, Australia), says that it is often grown as a winter cereal and mainly fed from rainwater rather than irrigation.

5. Coconut

Coconut trees grow in tropical areas like Thailand, Sri Lanka or the Pacific with plenty of water available. Yet, just like palm oil trees, they are often grown in deforested areas, leaving a high impact on tropical biodiversity. On a good note: ecosystems based on coconut trees enhance carbon sequestration in agroecosystems.5

It is not easy to make a choice and there does not seem to be a satisfying answer to the question of “what is the right milk alternative”. But here is a suggestion: why not mix it up a bit? In the end, moderate consumption has often proved to be a smart solution.

Additionally, to the links and sources provided, the author has interviewed both Joseph Poore and Thomas Nemecek for other projects.


Created by Kirstyn Byrne

August 13, 2019 Katharina Kropshofer By Katharina Kropshofer Follow

References

  1. Poore, J, Nemecek, T (2018): Reducing food’s environmental impacts through producers and consumers. Science Vol.360, Issue 6392, pp.987-992. Accessed 8 July, 2019.
  2. Poore & Nemecek (2018) Science; additional calculations for plant milks, milk chocolate, and pasta. Accessed 14 August, 2019.
  3. Kritte, K et al. (2018) High nitrous oxide fluxes from rice indicate the need to manage water for both long- and short-term climate impacts. Proceedings of the National Academy of Sciences of the United States of America. 115 (39 (pp.9720-9725)).
  4. Spring, A (2018). 'Milk' mania: why most alternatives aren't great – but camel milk just might be. The Guardian. Accessed 14 August, 2019.
  5. Ramachandran Nair, P K et al. (2019). Climate Change, Carbon Sequestration, and Coconut-Based Ecosystems. Springer: The Coconut palm – Research and Development Perspectives (Namppthiri K, ed.). pp. 779-799
  6. Chalupa-Krebzdak, S et al. (2018). Nutrient density and nutritional value of milk and plant-based milk alternatives. Elsevier: International Dairy Journal, Volume 87, pp 84-92.