Science·What on Earth?

Why potato milk, a newcomer to plant-based dairy, may be the most sustainable option

In this week's issue of our environment newsletter, we look at the emergence of a new player in the non-dairy milk game and ways of greening the music industry.

Also: Have emissions gone up on Trudeau's watch?

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(Sködt McNalty/CBC)

Hello, Earthlings! This is our weekly newsletter on all things environmental, where we highlight trends and solutions that are moving us to a more sustainable world. (Sign up here to get it in your inbox every Thursday.)

This week:

  • Why potato milk, a newcomer to plant-based dairy, may be the most sustainable option
  • A playbook for greening the music industry
  • Fact check: Have carbon emissions risen under Trudeau?

Why potato milk, a newcomer to plant-based dairy, may be the most sustainable option

(Submitted by Eva Tornberg)

Non-dairy milks made from oats, almonds and soybeans have become commonplace in grocery stores and coffee shops, but this fall, a new competitor is making its way to select cafés in Canada: potato milk. 

The product was developed by Eva Tornberg, a professor with the department of food technology, engineering and nutrition at Lund University in Sweden. She says she saw an opportunity to create sustainable milk with potatoes because they contain high-quality proteins that are transformed into milk by adding rapeseed oil, chicory fibre and pea protein.

"Potatoes saved people from starving during the 19th century," said Tornberg, who is also head of innovation and development at Veg of Lund, the Swedish company behind potato milk, which is marketed as Dug. "It has everything: good protein, high starch content and high vitamin C content."

Potato milk is currently only available in Sweden, U.K. and China, but Tornberg said it's been a hit among consumers, and they've nearly run out of stock. She credits the milk's success to its creamy texture and rather neutral taste.

Potato milk might also be the most environmentally friendly milk option. Tornberg's research revealed it takes 56 times less water to grow potatoes than it does to produce almonds.

The potato is one of the most productive and easy-to-grow foods in the world. Potatoes are very water- and land-efficient, meaning they produce more food per square metre and use less water than many other plants.

But how sustainable is it? Let's compare it to other milks.


Tornberg said it requires 16,000 litres of water to produce a kilogram of almonds, compared to 270 litres for a kilo of potatoes. And about 80 per cent of the world's almonds are grown in California, which is experiencing a record-breaking drought. 

"Almonds are grown in Mediterranean[-type] climates, where there is a lot of sun and not a lot of water," said Alissa Kendall, professor of civil environmental engineering at University of California, Davis. "Almonds take a lot of water to grow and that water is often irrigated instead of rain-fed water. You end up using groundwater or surface water to grow the food."


Soy milk performs better in terms of water use, averaging around 2,500 litres of water per kilogram of soybeans, but studies have found that soy milk is the worst plant-based milk in terms of greenhouse gas emissions. That's largely because of the clear-cutting that can occur to make space to grow soy, which ends up releasing more carbon.

Kendall, who studies the environmental impacts of agricultural systems, said it really depends on where the soy is being grown. 

"Soy grows all around the world and is then turned into soy milk, so some of the really high numbers are generated from studies in Europe that assume that the soy is grown in Brazil and and has some responsibility for deforestation," said Kendall.

Soy milk can be more sustainable when grown in other parts of the world, she said, especially when it's grown closer to where you, the consumer, live.


Oat and potato milk have comparable carbon and water footprints, but according to Tornberg, growing potatoes is twice as efficient as growing oats in terms of land use. 

"Potatoes are more productive than other plant bases that are used in milk." 


Despite some of their shortcomings, Kendall said all plant-based milks perform better than dairy milk in terms of water use, carbon footprint and land use.

"With dairy, you have to feed cows a lot of feed, and on top of that, they generate methane while they metabolize all that feed and produce milk, so their carbon footprint is huge," she said.

Not only that, but she said growing cattle feed requires a lot of water and dairy processing is an energy-intensive process. 

Choosing the most sustainable milk

While potato milk seems like a strong, sustainable option, Kendall cautions that where and how your vegan milk is packaged can have a bigger impact on the environment than its production. 

"These plant-based milks are actually mostly water, meaning that there's not much of the plant in the milk," said Kendall. "So just like any product where most of the product is water, things like shipping and packaging are actually pretty important to think about."

Kendall recommends people check labels to see where plant-based milks are packaged. Some companies package the milk closer to where it is sold, which saves shipping and is thus better for the environment.

Maya Lach-Aidelbaum

Reader feedback

In our Aug. 26 issue, Emily Chung wrote about the proliferation of "free stores" that divert clothing and household goods away from landfills. Here's what you had to say:

Peter Koppisch, director of public works for Seguin Township, Ont. (near Parry Sound): "We have had a reuse centre at our landfill for many years. It has helped to divert tonnes of material from the landfill. Prior to COVID, we would accept donations for goods for the fire department or a charity. This option has not yet been reintroduced due to COVID."

Brian Lussin, near Enderby, B.C.: "Our community, with the help of the Kingfisher Community Society, operated the local dump, as it was called back before recycling was a 'popular' label. We built a small building and called it a reuse store. That was in the 1980s. When the local regional district took over the site and designated it a 'transfer station,' we agitated to keep the service. Their concern was liability (the common excuse for governments to undo or not provide services). However, we prevailed by not taking any dollar offerings or service at the site. When the district chose to accept public bidding [from] a private contractor, the reuse building and service just kept quietly going on. Today it is a popular stop for anyone in need or simply curious. The children's toy section is a big attraction, as are furniture, tools, books and clothing. What to this community has been a ... longtime acceptance of shopping for used goods, we have noticed has grown most everywhere. 'Hey, where did you get the patio furniture?' 'Oh that? At the dump!'"

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Old issues of What on Earth? are right here.

There's also a radio show and podcast! With just over a week to go until election day, What On Earth host Laura Lynch questions party candidates on climate change and climate action. What On Earth airs Sunday at 12:30 p.m., 1 p.m. in Newfoundland. Subscribe on your favourite podcast app or hear it on demand at CBC Listen.

The Big Picture: Greening the music industry

While this summer's extreme weather has been another reminder that climate change is upon us, worsening conditions are prompting people from all walks of life to take action — including some in the entertainment business. Members of the British group Massive Attack (see photo below), who have advocated ways to make live music more environmentally sustainable, recently released a plan to try to do exactly that. The report, which was produced in concert with the U.K.'s Tyndall Centre for Climate Change Research, lays out a variety of measures, including eliminating private jet use and prioritizing electrified transportation for musicians; standardizing equipment among venues so that not so much of it has to be shipped; and encouraging venues do whatever possible to tap low-carbon energy sources. The report says that overall, "super low carbon needs to be baked into every decision," and that includes "routing, venues, transport modes, set, audio and visual design, staffing and promotion."

(Maya Hautefeuille/AFP via Getty Images)

Hot and bothered: Provocative ideas from around the web

  • An English Premier League game later this month is aiming to be the first "net-zero carbon football match." For the game between Chelsea and Tottenham on Sept. 19, players will be riding buses powered by biofuel and eschewing plastic water bottles, while fans will be encouraged to bike and choose plant-based snacks from the concession stands.

Fact check: Have carbon emissions risen under Trudeau?

(Eddy Kennedy/CBC)

The NDP attacked Justin Trudeau and the Liberals' record on climate change earlier this week, asserting that in spite of big promises, the Grits have failed to lower greenhouse gas emissions (GHG) in Canada.

In a news release, the NDP said Trudeau ratified the Paris Agreement with a commitment to reduce emissions to 30 per cent below 2005 levels by 2030, but "since then, Canada's emissions have only grown – faster than any other G7 nation."

With climate change a top issue for many voters this election, CBC decided to fact-check that charge.

Strictly speaking, the NDP's statement is true when looking at the official data currently available. In 2016, Canada's GHG emissions were 707 megatonnes (Mt) of carbon dioxide equivalent, according to government data. In 2019, the most recent year data is available, that number was 730.

But there are some important nuances to the issue, experts say.

Kathryn Harrison, a professor of political science at the University of British Columbia who studies climate politics, said it's "very likely that [emissions] fell from 2019 to 2020, because of economic contraction during the pandemic — but we don't have that data yet."

It's important to note that GHG emissions have mostly levelled off since the turn of the millennium after rising steadily throughout the 1990s.

One might conclude, based on the veracity of the NDP's claim, that the Trudeau government's policies on climate change aren't effective at reducing emissions. But that's not necessarily the case.

Felix Pretis, an assistant professor of economics at the University of Victoria and co-director of the Climate Econometrics Research Project. cites the introduction of carbon pricing, which came into effect in 2019.

"We wouldn't expect to see a change in emissions in the same year," he said. "When you put this sort of mechanism in place ... it takes a couple of years until we really see a change."

He adds that as the price on carbon goes up — the party plans to raise it to $170 per tonne by 2030 — the policy will have even more of an impact.

Harrison also points out that the Liberals have never promised that emissions reductions would be linear — that a drop would start in 2016 and continue to the Paris Agreement target in 2030. In other words, the Liberals may still be able to claim that their plan to reduce emissions and combat climate change is ambitious and on track.

"When you're on an upward trajectory, policies that are working may initially only level off emissions," Harrison said. 

(Also of note: Since signing the Paris Agreement in 2016, the Liberal government has adopted a more ambitious target of 40 to 45 per cent by 2030.)

Pretis adds that while Canada has seen a small rise in absolute emissions from 2016 to 2019, per capita emissions have been roughly flat. Most of the growth, the two experts say, is because of changes in transportation and oil and gas extraction.

The NDP may have good reason to single out Canada within the G7, though. Many European countries have seen emissions fall in the past few years, an accomplishment Canada cannot claim. 

The U.K. saw emissions drop 2.8 per cent in 2019 compared with the previous year. The European Union, Harrison said, deserves particular praise in this area, having seen a 3.7 per cent decline in emissions from 2018 to 2019.

"The EU has really led in ambitious climate policies." 

The U.S. has seen a decline in emissions since 2005, but not because of a determined government plan — it's largely because coal has become less economical as a power source.

While both experts say there are caveats to the NDP's criticism, they still say it's important that Canada lower emissions and not just keep them steady.

"It's important to be forward-looking," Pretis said.

"We will need high levels of carbon pricing in order to see a substantial change in emissions, and that's ultimately where we have to get to if we want to reach net zero, which is something that we should all be doing."

Fact check: True.

Richard Raycraft

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Editor: Andre Mayer | Logo design: Sködt McNalty

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