Bamboo skyscrapers and the future of the built environment 🎋🏗️
An interview with RIZOME co-founder Troy Carter
Today’s issue is all about the built environment, and especially the role bamboo will play in the decarbonization of building materials. We talk to RIZOME co-founder Troy Carter about the company he is building and why bamboo may just be a sleeping giant for both construction and deforestation. Key topics covered in this newsletter:
✅ Scope of emissions impact from building materials and construction
✅ Possible avenues to decarbonization in cement, steel, and bamboo
✅ Why bamboo isn’t a major building material today and why that will change
✅ A prediction for when we’ll see the first bamboo skyscraper 🏢
Thanks for reading!
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Embodied carbon represents ~10% of global energy-related emissions
Embodied carbon is defined as the cumulative GHG emissions impact from the mining, harvesting, processing, manufacturing, transportation, and installation of buildings. Essentially it accounts for the non-operational portion of carbon emissions from buildings (e.g., doesn’t include the ongoing impact from powering buildings). According to the World Green Building Council, buildings account for roughly 40% of global energy-related emissions, with roughly 10% attributable to embodied carbon.
In a recent interview, CarbonCure CEO Rob Niven said he expects the built environment will double over the next 40 years. That will require a massive amount of building materials and rapidly accelerate global warming if we keep the status quo.
Possible solutions to the built environment’s dirty footprint
The vast majority of embodied carbon’s footprint is attributable to cement and steel. Thus, one obvious path to decarbonization involves cleaning up the footprint of those two materials.
CarbonCure is one such company working on decarbonizing cement. The release of carbon in the process of creating cement is unavoidable. Cement is created by heating limestone, clay, and sand in a kiln at high temperatures. Due to the chemical makeup of limestone, CO2 is released during the heating process and typically emitted into the atmosphere as exhaust. CarbonCure’s solution is to close the loop by storing captured CO2 into concrete during the mixing process (note: cement is the primary ingredient of concrete). Though CarbonCure uses gas suppliers today, it’s easy to envision a future where cement exhaust is captured and subsequently put back into concrete with CarbonCure’s technology.
Steel is the other big pillar of the built environment’s footprint. Traditionally steel is made by super-heating coal. Recent efforts to clean up steel’s sustainability have focused on removing coal from steel production altogether. Boston Metal is one of the companies championing this cause with molten oxide electrolysis, a process that substitutes electricity for coal. To date, the company is able to produce alloys, which are nearing commercial viability. In the next five years, the company hopes to successfully produce zero-emission steel.
While decarbonizing concrete and steel are important endeavors, the assumption that they will continue to be the dominant building materials is worth interrogating. Though many consumer goods companies pride themselves on their bamboo products, it’s less common to hear the treelike grass mentioned as a possible solution to decarbonized buildings. Let’s find out why that’s the case and why it won’t be for long 🐼
Why bamboo needs to be a bigger part of the solution: An interview with RIZOME co-founder Troy Carter 🎙️
Troy Carter is Chief Strategy Officer and co-founder of RIZOME. He is also CEO and founder of Earthshot Labs—an open-source project mapping the world’s land use. Earthshot Labs leverages satellite imagery and other data to create an algorithmic engine to assess the implications of policy and investment decisions on landscapes.
Could you give us an overview of RIZOME and its mission?
RIZOME is a company that manufactures climate-positive building materials. We essentially make plywood out of bamboo. We are pioneering a supply chain for bamboo that will be as sophisticated and large as the supply chains for wood, steel, and concrete, which are materials that we hope will be replaced by climate-positive materials.
Right now, the paradigm with building is that the more you build, the worse the impact is on the environment. We'd love to change that. The more you build with bamboo, the better the climate impact because we draw down CO2 from the atmosphere and put it into the forest and the built environment.
What progress has the company made to date with respect to operations?
We're expanding quite quickly. Our operations are primarily in the Philippines, but our customers are mostly in the United States. We currently operate two factories and are building a third, which will be the largest bamboo manufacturing facility in the world. Our goal is to sequester 10 gigatons of carbon by 2050. That would be 1% of all anthropogenic carbon emissions since the start of human industrialization. It’s an optimistic target, but if we can hold ourselves to that target, that means there only needs to be 99 other solutions that address the climate and ecological crisis at the same level of scale. I'm optimistic that we have the technology that we need. All we need to do is implement it.
Can you talk about where bamboo comes from?
Bamboo grows in warm, tropical regions with lots of water. Historically, warm tropical regions have been undercapitalized and exploited through colonialism. Many of these countries have not developed a level of sophisticated industry in the ways the global Northwestern countries have. These regions have also historically had large lumber supplies with plenty of old-growth forests or virgin tropical rainforests. We're reaching a point in forestry where that is no longer the case. If you go to India, Indonesia, sub-Saharan Africa, Latin America, or Southeast Asia, there's almost 100% deforestation in most areas. As a result, the price of lumber is going up. Additionally, the areas that are forested are under monocultures that do not provide any biodiversity to the landscape or any other ecosystem services. That means there needs to be an alternative.
Equatorial regions will be seeing the highest population growth over the next 40 years of any region on Earth. They don't have trees left, so if they're going to build buildings, they're going to be building them out of steel and concrete. If they build them out of steel and concrete, we're going to hit climate thresholds that we don't want to hit because of the carbon footprint of those materials. Since trees have too long of a time to harvest for them to be useful to implement for construction at scale in these regions, we need an alternative. That alternative is bamboo.
Why haven't we already been using bamboo?
I've been asking that myself for years and there are a few very basic reasons. First is supply chain reliability. If you want to order 100 container loads of plywood made out of Douglas fir or southern yellow pine in Western Europe or North America, you can and you will know the exact specs of those materials. They'll be rigorously tested because it’s a very reliable supply chain. However, the supply chain for bamboo has not developed to that point, mostly because of these other historical factors of political destabilization resulting in deforestation over the past 50 years. Now that the land is all deforested, we need something to plant there, and bamboo is the answer. It’s worth noting you could order bamboo panels from China today; but the quality, volume, and timing are too inconsistent for the western construction market.
Another factor is species. We haven't needed bamboo as urgently as we do now because there's been plenty of trees. We haven't optimized bamboo for size and industrialization. In order to meet these criteria, bamboo requires large dimensions—say 10 to 12 inches in diameter and 100 to 120 feet high. Although this large species of bamboo can grow worldwide, few places on Earth currently grow the large variant we use. The majority of the existing $70bn commercial bamboo market is optimized for chopsticks, toothpicks, and cutting boards. We're the first ones optimizing for size to create lumber.
How is RIZOME planning to reinvent the relationship with local, indigenous communities and the land your farming in the context of the global forestry business?
There are a couple of reasons why bamboo is different than trees. In addition to the regenerative effects, bamboo grows really fast. With bamboo, there’s no clear-cutting, so the soil doesn’t erode. It’s just a type of grass—you can cut it over and over. In addition to the general ecological effects, it's inherently a decentralized product compared to trees. If you've ever tried to cut down a full-size Douglas fir tree, you'll know that it's impossible to do it yourself. It's just too big and heavy. But a poll of bamboo can be cut down by a farmer with a handsaw, who can take it to the factory and get paid for that material. Thus it's an inherently less centralized process because you don't need large expensive machinery. Also, the capital expenditures for the processing equipment can be put in very rural areas in developing countries. We primarily operate in Mindanao in the Philippines. It's a low tech, low skill operation.
So how are we doing supporting local communities? One, we've partnered with indigenous groups all over Mindanao to support them in earning ancestral domain rights. By retaining agency over their land, locals can participate in global carbon markets. We give them bamboo to plant, which they can use to revitalize their native forest and drive economic growth to meet their food security needs. We also benefit because we get more supply.
We're also doing business in a way that doesn’t require us to extract all the value out of the system. We do what we do quite well: manufacturing bamboo plywood and giving local people access to enter global carbon markets. RIZOME works on a Build-Operate-Transfer model where we start a factory, operate it for two years, and then give it to locals to continue operations. At that point, we're just a good customer.
There are two components to the business—creating bamboo building products and creating carbon offset projects. On the offset side, how do you measure impact?
We use Verra or the VCS methodology for officially calculating carbon removals that physically remove carbon dioxide from the atmosphere and put it into biomass. That's the part that we can get paid for, where we take CO2 from the atmosphere and put it into the forest. Once we start cutting down bamboo, the methodology officially undercounts the benefit. By frequently harvesting, we maintain a high growth rate for the plant and maximize carbon sequestration. Growing ten times faster than trees, bamboo maxes out growth at about ten years. We de-risk the carbon stock by putting it into the built environment rather than leaving it in the forest. We've seen big wildfires in Northern California and Oregon as an example, which essentially releases all the carbon back into the atmosphere. We're de-risking it by putting it into the built environment and then we can harvest it every year to maintain that cycle where we pull carbon dioxide from the atmosphere and put it into buildings. That part of the methodology is not currently officially counted, although our internal data shows that it's really high. Also, if we're replacing wood, steel, or concrete, these are all materials that have much more drastic ecological impacts. We estimate there's about a 40% benefit in choosing bamboo over a portfolio of these other materials.
Who are your customers right now?
Right now, we sell to wood distributors who sell to manufacturers of doors, windows, floors, and other interior industrial components of houses. These are very high margin, high value uses because they're replacing hardwood products like tropical hardwoods or maple. Hardwoods are becoming hard to find, and they're being harvested at younger and younger ages. You also basically cannot find tropical hardwoods anymore, so as a hardwood replacement, it's really valuable.
As our production process becomes more efficient and our scale gets larger, we will be able to start competing with structural products like cross-laminated timber (CLT), laminated veneer lumber (LVL), conventional plywood, oriented strand board (OSB), and other engineered-wood products. Within a year or two, we will be at price parity with most of these structural products. Over the course of the next seven to ten years we will be much cheaper.
The moment your product hits price parity, would we see construction companies start to adopt bamboo?
There are a few different issues here. One is familiarity with the material. I believe that in ten years, it will be obvious that bamboo would become a major construction material. Right now, it's only obvious to a few people. We're making it obvious to the entire world. To do that, we have to dramatically increase the amount of supply that's available and increase the sophistication and reliability of the supply chain. Everyone in the industry—the code compliance organizations, the lumber companies, and the architectural newsletters—talks about embodied carbon. Everyone knows construction is one of the largest contributors to CO2 emissions on Earth. That has to change, so there's big momentum for us. Whether from regulatory pressure or their own sustainability pledge, every company building a new building has to change what they're building with. We believe we're going to see a lot of mass timber built, and anything that can be built with wood can be built with bamboo.
Are there other climate-positive materials besides bamboo that can scale?
Climate positive building materials are tricky. I don't know of any other building material that's scalable right now in the same way that bamboo is because it can fit commodity sizes of existing construction materials. For instance, we can make quarter-inch, half-inch, three-quarter-inch plywood, and it fits in just like any other plywood. You can't say the same thing about cob, hempcrete. or other more ecologically friendly endeavors.
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If you had to guess, when do you think we will see the first bamboo sky-scraper?
I want to say five years, but the reality is more like 10.
For someone reading this who isn’t from the construction/architecture world, what action or continuing ed would you recommend they take concerning their built environment?
Very few people are in a place where they're making decisions about the materials of the building they're living or working in. Thus, I have very few recommendations as it's mostly a developer, architect, investor, and/or policymaker decision. Awareness is always great though. Just being aware that one of the largest ecological footprints you have is the ecological footprint of the building that you're sitting in.
What’s a book you’ve read recently that left an impression on you?
One recent book that I read was The Ministry for the Future by Kim Robinson. It's a climate change book that is both scary and optimistic.
What’s your climate hot take?
I believe that nature does not need to be protected from human beings. I believe that humans serve an important ecological function and that the most effective way to conserve non-human landscapes is by incorporating human beings into the landscape and reclaiming our ecological role.
Sources: World Green Building Council, AIA California
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