What are the environmental impacts of plant milks versus dairy milk? Which is the most sustainable?
The more popular plant milks get, the more they are attacked by the dairy industry, farmers and self-proclaimed experts. So how sustainable are they compared to cow’s milk? To accurately answer that question, let’s look at the environmental impacts of plant milks versus dairy milk
What is milk?
That might seem a strange question, yet it is one we really do need to carefully consider because we tend to make a lot of assumptions based more on habit than facts.
All mammals’ milk is a mixture of water and tiny droplets of fat providing a suitable environment for other nutrients and hormones that need to be delivered to the offspring.
All human babies need breastmilk – or formula as an alternative – so we are innately hardwired to like milk even though human milk is different to cow’s. We enjoy the taste and milk makes things nice and creamy. However, after weaning, we don’t really need milk – not even for calcium as there are many other sources – we simply like it.
Enter plant milks – and although we tend to think otherwise, they are not a modern invention! Historically, people have used all sorts of plant milks because they are easy to make and digest. Coconut, soya, and almond milks have been around for centuries if not millennia! They all have a few things in common: they contain no animal hormones, lactose or cholesterol and require much fewer resources than cow’s milk.
What goes into the production of cow’s milk?
It all starts with a calf. The calf needs to drink – usually a factory-manufactured milk substitute. Soon enough she needs to eat too and she eats a lot! Cows usually get a mixture of hay/straw and grass or silage and there’s also cattle feed made from wheat, barley, oats, corn, soya, fats and molasses.
Each cow inevitably burps and farts and because of how cattle digestive systems work, fermenting the food eaten, cows produce surprisingly large amounts of methane – a greenhouse gas 25-86 times more potent than CO2 in its climate change effect. Add that to it the urine and faeces cows produce, usually stored in ‘slurry lagoons’, emitting other greenhouse gases, and you may begin to understand why cow’s milk has 2.5-4.2 times bigger carbon footprint compared to plant milks.
How are plant milks produced?
All plant milks require small amounts of plant ingredients and some water. In general, there’s about 3-10 per cent of the plant, 90 per cent water and tiny amounts of other ingredients, such as calcium, natural stabiliser, sunflower oil or vitamins (in fortified versions). Cow’s milk contains a similar amount of water (87-90 per cent).
There are, of course, differences in how the crops for the milk are grown but it’s always a straightforward process. A crop is grown using water and sometimes fertiliser, harvested and used to make plant milk.
What’s the carbon and water footprint of dairy milk?
Because of all the above, cow’s milk has a much bigger impact on the environment than plant milks. Scientists have done all the hard work and calculated everything, so you can see it in this handy table (based on data from Poore and Nemecek, 2018):
To put it into perspective – to produce one litre of cow’s milk, you need 22 times as much water as what’s needed for one litre of soya milk and 18 times more land than for almond milk.
Many people find the figures surprising, but they do show very clearly that there is a dramatic different in the environmental impacts of plant milks versus dairy milk, especially when you consider the three most important elements of greenhouse gas emissions, water usage and land use.
Are some plant milks more sustainable than others?
There are many factors to consider in how sustainable a product is. However, all plant milks are more sustainable than cow’s milk – the evidence is clear.
Nonetheless, let’s consider the environmental impacts of the different plant milks.
Soya milk
Soya has received a lot of bad press because of the Amazon deforestation. Swathes of the rainforest have been cleared for cattle grazing and soya cultivation. However, nearly all of this soya is grown for livestock feed – fed to pigs, chickens and cows. On the other hand, most soya milk brands available in Europe use Europe-grown soya.
Sustainable soya cultivation in Europe is now the norm and is good for the soil too! Soya plants bind nitrogen in the soil, enriching it, and they require less fertiliser than many other crops.
Almond milk
Almond milk has also been subject to criticism because almonds are thirstier than many other plants. The world’s largest almond producer is California, which has been suffering severe droughts and that’s where the criticism comes from. However, dairy milk requires still more water than almond milk and California uses less water to grow almonds than it uses to grow alfalfa for livestock feed.
Spain is the second biggest producer with a long tradition of almond cultivation. Almond farmers use rainwater for irrigation where possible and have been reducing water usage in general to conserve resources (Expósito and Berbel, 2020). And let’s not forget that almonds are trees and as such capture CO2 and release oxygen, and their roots help to prevent soil erosion.
Rice milk
Rice is grown in flooded rice paddies and because those paddies produce methane, rice milk has a higher greenhouse gas impact than other cereal crops. Yet, it’s still less than a half of what cow’s milk produces (see the table above).
Oat, hemp and pea milks
All these crops are or can be grown locally, don’t require much irrigation or fertilisers and are beneficial to our health. There is no downside but if you want the most sustainable option, choose organic versions of these because that means no dangerous pesticides were used.
Coconut milk
Coconut plantations are scattered across subtropical coastal zones and while coconut growing is environmentally friendly, it’s the farmers that often struggle to make ends meet. Volatile market prices of coconuts mean they often don’t get paid enough. From this point of view, the sustainable choice is the one that keeps coconut farmers out of poverty – Fair Trade products.
The choice is yours
Whichever plant milk you choose, it’ll be a more sustainable option compared to cow’s milk. If you want to be super-sustainable, you can make your own and so reduce the use of transportation and packaging. But if you’d rather try a few more options, check out our Vegan’s guide to plant milks!
This article has been provided by Veronika Charvátová MSc, a biologist and Viva! Health researcher. Veronika has spent years uncovering the links between nutrition and good health and is an expert on plant-based diets.
Viva! is the UK’s leading vegan campaigning charity: registered charity number 1037486.
Viva!health is a major resource on vegan health and nutrition for health professionals and the public www.vivahealth.org.uk
References
Expósito A and Berbel J. 2020. The Economics of Irrigation in Almond Orchards. Application to Southern Spain. Agronomy. 10. 796.
Poore J, Nemecek T. 2018. Reducing food’s environmental impacts through producers and consumers. Science. 360 (6392): 987-992.