With veganism on the up, the plant-milk industry has grown hugely over the past few years. But it’s not only vegans who are turning to plants for their milk. Promoted as a ‘healthy’ alternative, plant-milks are becoming trendy. Some go as far to say they could be a solution to the ever worrisome issues of climate change and environmental destruction. The truth about the environmental impacts of cow’s milk and it’s plant alternatives needs exposing.
CLIMATE CHANGE – should we be worried?
The answer is yes, we should be. Global CO2 emissions are still rising despite efforts being made to halt them. Agriculture contributes to 24% of human-induced emissions worldwide. Environmental impact of agriculture, however, is not limited to greenhouse gas emissions – the subjects of global deforestation and water depletion are highly relevant. With the growing population, the consequences of our farming habits will continue to escalate at alarming rates unless we take action by changing how we produce our food and adjusting our diets accordingly.
But what’s wrong with milk?
Although the meat industry is topping the charts in terms of greenhouse gas emissions, the dairy industry is pretty high up there and, consequently, has considerable scope for cutting emissions.
Cow’s milk has a Global Warming Potential (GWP, kgCO2-eq/L) of 1.39. GWP is a comparative measure used by analysts when studying the greenhouse gas emissions of different products. This probably won’t mean much to most people, but it’s useful way to compare the environmental impact of different milks (see Figure 1).
The emissions generated in cow’s milk production come from direct and indirect sources. These include manure storage, animal feed production and, most prominently, methane produced by cow farts.
Are plant-milks really that much better for the environment?
Each plant-milk has varying impacts on the environment. It can be hard to decide which one to buy, but with the assessments made here, a more informed decision can be made.
Soya milk has been the leading milk substitute for years. Unlike many of its competitors, soya milk has a nutritional profile most similar to cow’s milk, with high levels of protein and calcium (see Figure 2). Therefore it is considered a more suitable substitute for children and those at risk of nutrition malnourishment.
Soya milk has a GWP of 0.88, just over half that of cow’s milk.
As the 4th largest crop worldwide, soybean farming is responsible for a huge amount of deforestation, particularly in South America. The environmental impact of deforestation is significant, leading to soil and water degradation, biodiversity loss and considerable carbon loss. As a result of this, soya milk receives a large amount of criticism.
However, the majority of soybeans grown are used in producing animal feed – a fact often neglected. Of the 33.9 million tonnes of soya imported into Europe in 2013, over 90% was used for animal feed. In fact, on average, 33g of soya goes into to producing a litre of cow’s milk. This seems rather a lot considering that soya milk has only between 100-200g of soya per litre (depending on recipe/production). You may also be interested to know that for each kg of beef, 456g of soya is used in animal feed for the cow, with chicken using a whopping 1.09kg of soya per 1kg chicken.
In this respect, soya milk maybe shouldn’t receive as much criticism as it does.
In recent years, almond milk has become incredibly popular. Although almond milk has a relatively low GWP of 0.42, its water footprint surpasses its competitors. Roughly 80% of the world’s almonds are grown in California and there has been high concern over the vast quantities of water involved in the farming of almonds, putting the state under high stress.
There is limited data on the water footprint of processed almond milk. The water footprint of shelled/peeled almonds alone is a huge 16,095 m3ton-1 (cow’s milk has a water footprint of 1,020m3ton-1). However, the composition of almond milk is mostly water – Alpro almond milk contains only 2.3% almond. So, despite the water footprint of almonds being very high, almond milk itself has a water footprint less than you might expect.
COCONUT, OAT and the rest…
There is relatively little data available for other milk alternatives. Coconut milk was shown to have a relatively low GWP of 0.42, whereas oat milk has an even lower estimated GWP of 0.21. But what about hazelnut, cashew, rice and hemp milk? Few reliable studies could be found detailing the environmental impact of these milks. With the recent rise of plant-milk sales and the call for more-environmentally friendly diets, the need for more reliable research is great.
So what does this mean?
All the plant milk alternatives shown here have considerably lower GWPs than cow’s milk. But which is the best? Oat milk comes top in terms of low GWP and it doesn’t fair too badly nutritionally as a substitute for cow’s milk. You can even make your own at home with little effort. Soya milk is supposedly the worst of the the plant-milks for environmental impact in terms of GWP. BUT, as a direct milk substitute, it should still be considered. Taking into account almond milk’s water footprint it should probably best be avoided.
Although each plant-milk has its own disadvantages, a shift towards non-dairy products is a valid action in reducing our environmental impact. Other dietary modifications may be considered first if wishing to make the biggest differences. The most obvious of these would be to reduce meat consumption – specifically beef. Keep this happy cow smiling!
 Chen, S. (1989). Principles of soymilk production. Food Uses of Whole Oil and Protein Seeds, 40-86.
Feature image sourced from BreastHealth.org