Science·What on Earth?

Buildings made with fungi could live, grow — and then biodegrade

In this week's issue of our environment newsletter, we look at how mycelium could be used to make sustainable building materials and why RBC ranks so high on the list of banks funding the fossil fuel industry.

Also: The importance of protecting old growth forests

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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:

  • Buildings made with fungi could live, grow — and then biodegrade
  • Here's a carbon capture strategy: Protect old growth forests
  • RBC is one of the world's top bankers to the fossil fuel industry

Buildings made with fungi could live, grow — and then biodegrade


There's been buzz lately about mycelium, a material made from fungi that's being used as a greener substitute for leather and plastic in products such as clothing and packaging.

But more than a decade ago, designers were talking about mycelium's potential for another use — as a building material. This could lead to the construction of healthier buildings made of components that are grown instead of manufactured and can be triggered to biodegrade at the end of their life, instead of piling up as demolition waste in landfills.

Mycelium is the root network of fungi, which in nature help decompose materials like wood and leaves, recycling their nutrients and storing their carbon in the soil. 

But it can also be grown by humans from waste materials such as sawdust or agricultural residues such as plant stalks and husks, recycling them and generating a new material or product within weeks in a low-cost, low-energy process compared to traditional manufacturing. 

It can even be grown to a particular shape, similar to the way concrete is cast. 

Joe Dahmen, an associate professor at the University of British Columbia School of Architecture, said people first became interested in mycelium for construction about 15 years ago as a substitute for foam insulation, which isn't biodegradable and can pose a potential health hazard.

"There's a real tie-in here with healthy buildings," he said, noting that he became interested in mycelium as a replacement for formaldehyde-based glues.

Mycelium can be used for a variety of building elements. For example, the Italian firm Mogu already sells flooring tiles and soundproofing wall panels made from mycelium. The British biotech firm BIOHM is working to develop mycelium-based insulation panels.

A number of projects around the world have also used mycelium bricks as a construction material. They include Hy-Fi, a pair of two-storey cylindrical towers that won MoMA's Young Architects Program competition in 2014, and the Mycelium Martian Dome installation by Toronto artist Tosca Teran at the Ontario Science Centre in 2019.

In most such projects, the mycelium is no longer growing. But Dahmen has experimented with projects in which the fungi remained alive, fusing bricks together and even producing mushrooms. 

They include a brick wall and a set of benches created with his wife, Amber Frid-Jimenez, Canada Research Chair in Art and Design Technology at Emily Carr University, and their design studio, AFJD.

"As architects and designers, we were really interested in the idea of a material that might aggregate and continue to grow once it was in the shape or form of whatever it was we were designing to," Dahmen said. 

He said fungi can also go dormant to get through dry spells. Indoors, mycelium tends to dry out, becoming stronger and less spongy over time. 

"But that doesn't mean they can't reawaken later.… What seems exciting to me is the idea that we could include these materials in a building and they would be inert and non-toxic during the life of the building. Then, in the right conditions, they might reawaken and start digesting the materials."

Dahmen acknowledges it's important to be able to make sure it only happens at the right time, and the challenge of designing materials for long-term investments such as buildings is bigger than designing materials for products such as clothing.

"I'm also equally confident that we will ultimately get to building components made of these materials," he said. "It just might take a bit longer."

Emily Chung

Reader feedback

Larry Herr: "Thanks for [last] week's story on ethical travel. I decided to give up air travel by jet, for pleasure, seven years ago when I learned how damaging it is to the environment, due to its very high carbon footprint. I have since learned that one can travel virtually to almost anywhere on the planet via YouTube, with zero carbon footprint. While virtual travel is not good for the airlines and tourist businesses and all of their employees, it is great for the environment." 

Janet Duval: "We were taking one trip per year before the virus, and bought carbon offsets from Less, but still felt guilty about flying. Is there any ethical reason that it IS good to fly? We are in our 70s, and Life Happens, so we may not be able to wait for Richard Branson's low-carbon jet fuel."

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Old issues of What on Earth? are right here.

There's also a podcast! Host Laura Lynch gets reaction to the Supreme Court of Canada's ruling on carbon pricing. Subscribe to What on Earth on your favourite podcast app or hear it on demand at CBC Listen. What on Earth the radio show airs Sundays at 12:30 p.m., 1 p.m. in Newfoundland.

The Big Picture: Forest protection as carbon capture strategy

In recent years, it has become quite common to hear current and former titans of industry (see: Bill Gates) tout the importance and necessity of new technologies to sequester carbon to keep it out of the atmosphere. While many of these carbon capture and storage (CCS) concepts sound promising, they are still in their infancy and require a great deal of energy to operate. Many scientists say that more natural methods are preferable. While many have espoused the virtues of tree-planting, this essay suggests that protecting old growth forests is even more vital and effective in pulling carbon out of the air. Why? Trees that have reached maturity — from root to bark to canopy — deal better with climate variability than young trees and store more carbon on an annual basis. Some of the oldest trees around — such as the redwoods and Douglas firs of the Pacific Northwest — can live for 800 years, which makes them very effective at long-term carbon sequestration. But protecting them from clear-cutting requires constant vigilance — as activists in B.C., for example, know only too well.


Hot and bothered: Provocative ideas from around the web

  • Monday was World Water Day,  an annual United Nations initiative to remind us that many parts of the planet do not have dependable access to clean water. In its report this year, the UN noted that roughly four billion people experience severe water shortages for at least one month a year, and about 1.6 billion struggle to access a clean, safe water supply.

  • The Supreme Court of Canada has ruled that the federal government's imposition of carbon taxes on provinces that do not have their own pricing mechanisms is constitutional. Writing for the majority in the 6-3 ruling, Chief Justice Richard Wagner said carbon emissions are by their nature diffusive and "extraprovincial," and that excluding any province from a pricing scheme "would jeopardize its success in the rest of Canada."

RBC is one of the world's top bankers to the fossil fuel industry

Environmental groups are calling on the federal government to update the mandates of financial regulators to compel financial institutions to issue science-based climate reports and plans. (Mark Blinch/Reuters)

Canadian banks have a fossil fuel addiction. But it's not just a Canadian problem.

The latest study of corporate data from 60 of the world's largest banks shows that rather than cutting back on the funding of fossil fuel projects since the 2016 global agreement to limit greenhouse gases, they have increased that funding to $3.8 trillion US in the past five years.

The report outlining the data, titled Banking on Climate Chaos 2021, is the 12th annual tally of fossil fuel financing. It's compiled by a group of seven climate advocacy organizations, including Rainforest Action Network and the Sierra Club.

While a crash in the fossil fuel business during the pandemic led to a sharp drop in investment growth in 2020, the report's authors fear a recovery this year will lead to a "snap back to business as usual."

Although U.S. banks, including JPMorgan Chase, have committed to establishing emissions targets for their financing portfolios in line with the Paris climate accord, the report declares North America's biggest bank has also been "the world's worst fossil bank" over the past five years, lending $317 billion to the industry.

U.S. banks lead the pack, but Canada's Royal Bank has the dubious honour of punching above its weight. (Four Canadian banks are in the top 20, including RBC, TD Bank, Scotiabank and Bank of Montreal.) People close to Canada's banking industry say banks like RBC are having trouble changing direction.

"There's a lot in the Canadian psyche and history that is wrapped up in the fossil fuel economy, and we're feeling some of that inertia right now," said Laura Zizzo, co-founder and CEO of Manifest Climate, a Toronto company that advises financial institutions across North America on strategies to navigate climate change.

Working with Canada's big banks — though she wouldn't say whether RBC was a client — Zizzo said she is convinced people at the highest corporate levels are committed to change. It's just happening more slowly than climate activists would like.

Asked why Canada's biggest bank continued to lend large amounts to the fossil fuel industry — $160 billion over the past five years — RBC reaffirmed its commitment to net-zero emissions, including a promise of $500 billion in sustainable finance by 2025. It said it was also the first bank to commit to not lending to resource projects in Alaska's Arctic National Wildlife Refuge.

But in a country where there is so much political and economic pressure for oil and gas development, RBC said that to be successful, its move to net zero must be gradual. The transition "must be done in an inclusive manner that brings all sectors and communities along or we won't achieve the support we need to meet these goals," RBC said in an email.

Mark Carney, who was governor of both the Bank of Canada and Bank of England before becoming head of impact investing at Brookfield Asset Management, has warned that when financial institutions take a stake in long-term fossil fuel projects, it's not just bad for the environment.

He and others say a rush to get out of those investments as the climate crisis worsens could create a financial risk for the entire economy, including banks, pension funds and insurance companies. It also creates a risk for ordinary Canadians who depend on those institutions, as well as for investors and employees.

Zizzo said part of the difficulty for banks is that their normal investment horizons are two years or longer. That means "they are all still too short to think about the longer-term issues of climate," she said. "It's taking time before it actually percolates into the risk-management functions of these financial institutions."

She said that, so far, banks have been better at expanding investments in greener projects than in paring back on fossil fuels.

Adam Scott, director of Shift, a Toronto-based group that monitors pensions for climate risk, said many bankers fail to recognize that global warming requires a quick phaseout of fossil fuels.

"When you build new fossil fuel projects, you're locking in emissions for decades to come. So an investment today in new fossil fuel makes it harder to address the climate crisis," Scott said.

"The banks are pouring money into making this problem harder, and that just has to stop."

Don Pittis

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Editor: Andre Mayer | Logo design: Sködt McNalty

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