Which is the most environmentally friendly milk?

Cutting back on dairy

More and more people are switching to plant-based milk as they switch from dairy. With the average person in the UK drinking almost 250 litres of milk every year, and dairy contributing 4% of total greenhouse gases worldwide, it’s a switch that can help cut our personal carbon footprints.

But with so many alt-milks now on offer, many people want to know the best switch. 

We look at the carbon footprint and water usage of each of the main plant milks to answer this question and the results are clear. Oat and soya have the best combination of low carbon emissions and lower water usage of all the plant milks while also offering considerable savings compared to dairy.

If you’re looking for the most environmentally friendly alternative to dairy milk, then oat or soya is the answer. Here’s why.

Why Carbon and water matter

To get any type of milk to your home, it needs to be grown, harvested, processed, packed and delivered to the supermarket. Each of these steps can create carbon emissions, and on the farm, you’ll need water. 

Compared to dairy, plant-based milk typically emits less carbon, and uses less water, because the process is direct – grow, harvest, process. However, for dairy, not only do animals need to be fed, requiring crops to be grown and delivered to the farm, but cows also emit methane, a powerful greenhouse gas. That’s why dairy has a bigger carbon footprint than the entire aviation industry.

However, each plant-based milk, from almond to oat, is different, creating surprising differences in how they affect the environment. 

Oat milk

Oat milk is a good option for both low carbon emissions and water use compared to dairy. Academics have found that oat milk emits 70% less carbon than dairy for each litre of milk and uses more than 90% less water. Over a year, this can save hundreds of kilos of carbon for the average person. What’s more, oat milk now often matches, and even beats, dairy in taste tests and goes particularly well with coffee and cereal, two of the biggest uses for milk.

If you’ve not tried plant-based milk before, then oats are a great place to start and available in most shops and many cafés. You can use our handy try plant-based step to help you.

Soya milk

Soya is another popular plant-based milk that combines lower carbon and water use. Like oats, a lot of the soya used for milk is grown in Europe, and although its carbon footprint is just above oat milk, it makes up for it with lower water usage using an astonishing 95% less water than dairy. 

There are concerns about soya more broadly as a lot of deforestation in the Amazon is linked to soya production. However, 95% of Amazon-grown soya is for animal feed, and the other 5% not used for plant milk products. Indeed, it’s such a highly contentious area that some producers, including fellow B Corp Alpro, state clearly on the pack where their soya originates. 

Rice and almond milk

Two other plant milks need a mention. Rice is a good alternative with a lower carbon footprint than dairy but higher than oat or soya. This is because rice is grown in paddy fields, a process that creates methane which is a powerful greenhouse gas. Because rice is grown in water, it also has a much higher water footprint than oat or soya, using over 250 litres for every litre that makes it to your table. 

Almonds win out on the carbon emissions because almond trees remove carbon from the atmosphere as they grow and helps to reduce the overall carbon footprint as it counters the emissions from harvesting, producing, and transporting it. However, almonds need loads of water – over 370 litres for each litre. So just one glass of almond milk needs the same water as a 13-minute shower. Almonds are typically being grown in hot areas, such as California and Spain, putting further pressure on areas that are already feeling the effects of droughts exacerbated by climate change. 

The more unusual kinds of milk

Some shops now also stock coconut milk. Like almonds, coconut trees soak carbon into their trunks, branches, and roots as they grow. However, coconuts are typically grown in tropical areas, which are also home to much of the world’s rainforests. As a result, coconuts come with deforestation risk and so, if you are choosing coconut, check out the company you are buying from to make sure they source their coconuts sustainably. 


It’s not just the product of milk that creates emissions but also how it’s packaged. Most plant milk now comes in recyclable packaging, so to keep your footprint as low as possible, recycle it all the time. Recycling saves energy compared to making new packaging which means lower carbon emissions.

Some companies such as Milk and More, and Riverford, even offer oat milk in glass bottles now, so you can reuse them again, again, and again.

What next?

Now ready to take a step, so sign up to Giki Zero and try plant-based. If you want to try something new, you could go plant-based for a day.

If plant-based is already your thing, then maybe show someone else the benefits by making a plant-based meal for a friend

If you’re back in the office, share this article with your Office Manager or whoever orders the milk. We can make a greater impact if we help show the organisations we work for a way to cut carbon at home, and at work. Whatever you choose, enjoy your alt-milk and send us your recipe ideas using #ThinkCarbon.