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The dairy industry has a problem: the 270 million dairy cows on earth burp too much. About 6% of methane emissions from human activity come from cows’ belches and other releases (sometimes the gas goes the other way), says the UN.

With evidence of the damage mankind is wreaking on the planet mounting (see the Amazonian wildfires and fast-disappearing glaciers in Greenland), more and more Brits are dodging dairy and switching to plant-based. Twenty-three per cent now buy milk alternatives, up from 19% a year ago [Mintel].

Yet while environmental concerns are driving dietary changes, milk made from soyabeans - the crop described by Greenpeace as the ‘leading cause of deforestation’ in the Amazon - is Britain’s bestselling alternative.

So how much greener are plant-based milks really? And how do they compare with each other?

Plantbased milk infographics

Cows milk

Cows milk does take a heavy toll on the planet. For every litre produced globally, 3kg of greenhouse gases (mostly methane) go into the atmosphere, according to an influential study by Poore & Nemecek. That’s roughly equivalent to driving 10 miles in an average-sized family estate car for every litre of milk we consume. An average of nine square metres of land and 628 litres of water are also required.

“On a climate change basis, I’d say any plant milk is better than cows milk,” says Professor Sarah Bridle, who heads up Food Network+, a Science & Technology Facilities Council initiative. “You can’t get away from it: 5% of the 70,000 calories cows consume every day are burped out as methane.”

First Milk Cows

For every litre of milk produced globally, 3kg of greenhouse gases enter the atmosphere

The carbon footprint of milk does vary from country to country. “The UK’s footprint of milk production has been placed at 1.25kg per litre, making the UK amongst the world’s best in sustainable milk production,” says Dairy UK CEO Dr Judith Bryans.

But that’s still greater than the emissions Poore & Nemecek attributed to any plant-based milk. Which is no big surprise, given recent headlines.

Soy milk

What is surprising is how well soy milk comes off in the study, given recent concerns over its sustainability credentials. Globally, production of a litre of milk from soyabeans emits a kilo of CO2 or equivalent gases. That’s 2kg less than cows, 200g less than rice and slightly more than oat and almond milk. Soy milk requires the least water and land to produce, too.

These numbers don’t include the huge emissions linked to deforestation in the Amazon, the planet’s largest carbon sink. But they are difficult to attribute to any single crop. In Brazil - the world’s biggest soyabean producer - cleared land is often grazed before being given over to soya. And the bulk of the country’s crop is used as animal feed. Most soy milk sold in the UK is made with beans from Europe or Canada.

Almond Milk

Almond milk has potentially bigger problems. It has the lowest greenhouse gas emissions and its raw materials require the least land to grow, but it is by far the thirstiest plant milk. Producing a single litre of almond milk requires a whopping 371 litres of water.

Cows milk requires nearly twice as much as that, according to Poore & Nemecek, but that’s on a global basis. “Dairy cattle in the UK are almost exclusively rain-fed, and do not contribute to issues of water scarcity,” says Bryans. “We know this is not the case for almonds, which cause huge issues in the hot and dry regions in which they’re grown, contributing to drought and soil erosion. The key thing is to consider the impact of the food we’re eating to its local surroundings.”

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Source: Unsplash

Some have blamed almond growers for exacerbating California’s drought and indirectly fanning wildfires

Indeed, some have blamed almond growers for exacerbating California’s drought and indirectly fanning the wildfires that have devastated the state in recent years, pointing out the industry takes about 10% of California’s water to produce its crop.

Califia Farms, which exports almond milk products to the UK from the US, rejects this. “California is still the number-one dairy producing state and it takes 40% less water to produce our almond milk than it does cows milk,” says sustainability manager Eli Steltenpohl, pointing to recent efforts that have yielded a 16% cut in Califia’s water usage. “It’s unfortunate how consumer perception has been tainted against almonds. But, ecologically speaking, it makes no sense.”

Alpro sources its almonds from Spain and other Mediterranean countries. “Cultivation in Mediterranean areas, the nearest source of supply to the UK, is a small-scale, traditional industry,” says sustainability manager Greet Vanderheyden. “These orchards are less affected by problems related to mass cultivation and most of the production is rain-fed.” 

“It’s unfortunate how consumer perception has tainted against almonds. But, ecologically speaking, it makes no sense”

Still, that rain is becoming scarcer and more erratic. Mediterranean growers are increasingly facing the same drought conditions as their Californian counterparts. Wildfires are becoming more common across Spain, the world’s second-biggest producer of almonds.

This is another limitation of the Poore & Nemecek study. Wildfires release vast quantities of carbon into the atmosphere. But exactly how much is difficult to calculate and, clearly, blame for fires cannot be laid at the feet of producers of just one crop. It’s therefore impossible to include the impact of wildfires when calculating the greenhouse emissions of any given milk.

You can take an educated guess, however. Wildfires in the Amazon rainforest in Brazil have been blamed on farmers who have used fire to clear land for cultivation of soya and other crops, and raising cattle. The fires have released thousands of tonnes of CO2 into the atmosphere, while destroying vast swathes of the world’s most biodiverse forest.

“Ideally, we would look at the impact on biodiversity when calculating the footprint of different foods but this is really difficult to quantify,” explains Bridle. “There are other metrics like animal welfare and farmer wellbeing we should also take into account. Soya, for example, is great because it binds to nitrogen so requires less fertiliser.”

Oat milk

Oat milk, meanwhile, fares well in terms of its CO2 emissions and water use in the Poore & Nemecek study. Oats grow in more temperate climes, so are less associated with loss of biodiversity and wildfires than other crops. And, while oats need more land to grow than rice, soya or almonds, they require far less than cows.

“We use just 10% of the land that dairy uses,” says Carina Tollmar, sustainability director at Swedish brand Oatly, which is now the UK’s bestselling oat milk player. “Consumers are often so far removed from primary production so they have no idea how much feed cattle require or how much CO2 they produce.”

On the front of every pack of Oatly sold in the UK there’s a tab showing how much CO2 was emitted to produce, package and transport the product to store. The brand is now calling on its peers to do the same.

Lab-made dairy

Plant milks may be less environmentally damaging, but they have a key disadvantage in the eyes of more than a third of consumers: they just don’t taste as good as the real thing. Thirty-four per cent of consumers told us that in a recent Streetbees poll.

That could soon change. “An interesting development is the use genetically modified yeast to produce whey and casein protein in laboratories,” says Professor Sarah Bridle, author of forthcoming book Food and Climate Change Without the Hot Air. “The proteins are produced by feeding the yeast nutrients. This gives a milky taste without the product having ever been anywhere near a cow.”

This summer, US brand Perfect Day launched ‘the world’s first animal-free dairy ice cream’. Available in Vanilla Salted Fudge, Milky Chocolate and Vanilla Blackberry Toffee, the ice creams were made by mixing plant-based fats with dairy proteins produced by using GM yeast to ferment sugar in a lab. The fermentation process creates milk proteins and the yeast is then filtered out, meaning no GM material remains in the finished product.

This is just the beginning. Fellow Californian biotech startup New Culture is producing what it calls ‘cow cheese without the cow’ by growing casein in a lab. The company says this dairy protein is what gives conventional cheese its distinctive flavour, mouthfeel and texture, elements that are often lacking in plant-based alternatives. Both companies claim their products emit significantly less CO2 and use less water to produce than the real thing.

But there’s one key hurdle to overcome. Perfect Day’s ice cream was sold directly through the brand’s website for a whopping $60 for three pints, in a reflection of sky-high R&D and production costs. It may have sold out within days, but to achieve truly mainstream appeal, prices will have to come down.

Packaging

Packaging can make a big difference to the green credentials of both milk and plant-based alternatives. Most would assume chilled products would have a larger carbon footprint than ambient ones, because of the energy required to keep products cold. But that is not always the case. “We found that the carbon footprint of our ambient product is slightly higher than the chilled (440g of CO2 per litre versus 360g to 410g) because to keep the product aseptic we currently need to use aluminium in the packaging,” says Tollmar. “Aluminium requires a lot of energy to produce.”

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Ambient plant milks must use aluminium packaging in order to remain aseptic

Nevertheless, the greatest savings can be made at the farms. Poore & Nemecek calculate that 61% of the 13.7 billion tonnes of CO2 and equivalent gases emitted by the global food supply chain come from the farm stage of production. “One interesting statistic from the International Panel on Climate Change is that if cows are eating grass, 6% of the calories they consume are turned into methane, but if they’re eating more refined proteins only 3% is,” says Bridle. “The savings that can be made from things like transportation are negligible compared to the savings that can be made in farming.”

Livestock farming, in particular. Dairy UK says it has already achieved a 24% cut in greenhouse emissions and water use since 2008 and an 18% improvement in energy efficiency across UK dairy farms. By next year, it wants to have achieved a 30% cut in emissions on 1990 levels and says 40% of the energy used on UK dairy farms will be from renewable sources.

But “producers have limits on how far they can reduce impacts,” concluded Poore & Nemecek. “Most strikingly, impacts of the lowest-impact animal products typically exceed those of vegetable substitutes, providing new evidence for the importance of dietary change.” That spells further difficulties for UK dairy. And more growth for plant-based milks.