Credit: Unsplash / Nathan Dumlao

Food production is responsible for 25% of worldwide greenhouse gas emissions. It’s a huge factor in our personal environmental footprints, and in the environmental footprint of humanity as a whole. The production of animals for food has the most impact of all food types, responsible for approximately 15% of our worldwide greenhouse gas emissions.

That means that an action as simple as which type of milk you choose to drink in your coffee can add up to a significant amount of your daily greenhouse gas emission. This may seem counter intuitive initially — surely it matters more that we have a modern, energy efficient kettle, and only fill it with the amount of water we need, in order to make our coffee eco-friendly? In reality, though, if you take milk in your coffee, that will account for two-thirds of the carbon footprint of the drink.

A cup of coffee made with cow’s milk has produced around 53g of carbon dioxide equivalent (CO2e). The same coffee without milk equates to around 21g of CO2e — less than half the footprint. Studies estimate that switching to non-dairy milk will roughly half the emissions of that food item, so by swapping dairy milk for non-dairy that cup of coffee’s footprint reduces to around 26.5g CO2e. Again this may seem counter intuitive: non-dairy milks require much more processing to produce, and therefore surely use more energy? In this article we’ll delve into this, and look into why non-dairy milks are actually better for the environment.

“I suspect that most consumers underestimate the greenhouse gas emissions saved by switching from dairy milk to plant-based milk such as soy milk.” Dr Adrian Camilleri, a psychologist at the University of Technology Sydney.

We’ve been trained since we were children to view cow’s milk as a nutritious option, necessary for the development of our bodies, so it’s unsurprising that the reality of the impact of cow’s milk can be shocking — it’s a food item that we see as normal, necessary, and everyday. It’s also why it’s so difficult for people to accept that the dairy industry is unbelievably cruel and ultimately unethical. Think of advertising campaigns like ‘Got milk?’, which presented us with images of bodybuilders, rock stars and even Superman and told us that if we wanted to be strong like them, we needed to consume milk. Think also of the free or subsidized milk given to schoolchildren every day.

So let’s explore beyond the marketing and look at the facts of the environmental impact of different types of milk, dairy and non-dairy.

Cows milk

A 2018 study by researchers at Oxford University concluded that producing a glass of cow’s milk has at least three times more environmental impact than producing a glass of any non-dairy milk.

This is due to a combination of:

Greenhouse gas emissions : around 0.6kg per 200 ml glass. Cows are a major producer of methane (via their burps) which is thought to be around 20x more potent than carbon dioxide as a greenhouse gas.

: around 0.6kg per 200 ml glass. Cows are a major producer of methane (via their burps) which is thought to be around 20x more potent than carbon dioxide as a greenhouse gas. Land use : there are around 270 million dairy cows worldwide. That requires a hell of a lot of land space. Add on top of that the feed crops (mainly soy) needed to keep those 270 million cows alive, and the land required for that.

: there are around 270 million dairy cows worldwide. That requires a hell of a lot of land space. Add on top of that the feed crops (mainly soy) needed to keep those 270 million cows alive, and the land required for that. Water use: a litre of cow’s milk uses around 1050 litres of water to produce.

Soy milk

For a long time soy was the only, or at least the most readily available, option for the non-dairy milk drinkers amongst us. When compared to the environmental impact of cow’s milk, soy definitely comes out on top.

Greenhouse gas emissions : a 200ml glass of soy milk is responsible for around 0.195kg of CO2e. Research by scientist David Pimentel concluded that 1 calorie of milk protein requires 14 calories of fossil fuel energy to produce. In comparison, it takes just 0.26 calories of fossil fuel to make 1 calorie of milk from organic soybeans.

: a 200ml glass of soy milk is responsible for around 0.195kg of CO2e. Research by scientist David Pimentel concluded that 1 calorie of milk protein requires 14 calories of fossil fuel energy to produce. In comparison, it takes just 0.26 calories of fossil fuel to make 1 calorie of milk from organic soybeans. Water: a litre of soy milk uses around 297 litres of water to produce. This may sound like a huge amount of water, and it is, but it’s less than a third of the water needed to produce cow’s milk.

Land use is the potential downfall of soy milk, because it uses a lot of our land space currently. Significantly, parts of the Amazon rainforest are being deforested specifically to produce soy plantations. This is definitely concerning, but it’s important to remember that 85% of soy beans are currently used to feed animals and produce oil, rather than to make soy milk.

Almond milk

In terms of impact from emissions, almond milk could be a good choice:

Greenhouse gas emissions: a 200ml glass of almond milk is responsible for around 0.14kg of CO2e, making it a less impactful option than cow’ milk or soy milk in terms of emissions.

However, the issue with almond milk is the land and water use needed to produce it. Roughly 80% of almonds are currently grown in California, USA (although this may start to change, with the UK increasing growth recently), Farmers in the area have seen huge increases in demand in recent years, with around 44% more land being used for almond trees now than 5 years ago.

The major issue with almonds is that they’re an incredible thirsty crop: one almond needs on average 14.5 litres of water to produce. This amount of water consumption would be an issue anywhere, but in a state like California which is dry, arid, and very prone to droughts, it becomes magnified.

Oat milk

Greenhouse gas emissions : a 200ml glass of oat milk is responsible for around 0.18kg of CO2e. That’s slightly more than almond milk, but less than soy or cow’s milk.

: a 200ml glass of oat milk is responsible for around 0.18kg of CO2e. That’s slightly more than almond milk, but less than soy or cow’s milk. Water : a litre of oat milk needs about 48 litres of water produce. In terms of water, then, oat milk is much lower impact than other milks.

: a litre of oat milk needs about 48 litres of water produce. In terms of water, then, oat milk is much lower impact than other milks. Land: oats use 80% less land to grow than dairy milk requires.

Swedish oat milk producer Oatly put the greenhouse gas emissions of a litre of their oat milk at 0.34kg, which is a lot less than the general estimate above of 0.18kg per 200ml. This is largely due to their efforts towards sustainable packaging, transport etc — it’s just worth being aware that within each milk type, different manufacturers will also have more or less impact.

So which milk should I buy?

As you can see from the figures here, there’s a fair amount of variability between different types of milk when it comes to environmental impact. Judging from current data, it seems like oat milk is the most sustainable option, so that would be my best recommendation.

The key take away here, though, is that in terms of food the biggest thing that you can do for the environment is to start to reduce the amount of animal products in your diet, and dairy milk is a simple place to start with this.