Salmaan Craig had a glamorous career as an architect, helping construct and design some of the most celebrated buildings of the last 10 years, including the Louvre in Abu Dhabi, the Apple Campus in Cupertino, California, and the Bloomberg Offices in London. And he traded all that in for the less profitable world of academia—to delve further into a specialization that sounds drab but could prove revolutionary. Craig reimagines building facades as “biomimetic skins,” specially designed to adapt to each project’s local environment, thus controlling for drastic fluctuations in temperature. These new breathing buildings suggest a new way forward for sustainable architecture.
After a stint at Harvard, Craig is now a Professor at McGill University where he has the time to reconsider, from the most elemental materials, how we should build in the age of climate change. He is currently doing fascinating research into how future building projects could utilize wood as part of a dynamic interchange with nearby forests. Crucially, his work doesn’t just imagine a more ecological future, but also foregrounds how unchecked capitalism may prevent us from making these necessary changes. Just in time for Science & Society: Capitalism vs. Climate streaming live on March 4, architectural historian C. Kaye Rawlings and science journalist Dan Samorodnitsky met with Craig over Zoom to discuss the very specific ways architecture could adapt to the realities of catastrophic climate change.
One of the key ideas you’ve helped popularize over the past few years is “buoyancy ventilation.” Can you explain what this means in layman’s terms?
Buoyancy ventilation is a form of natural ventilation. When you think natural ventilation, people automatically think wind. Wind is fine, except it can be pretty unreliable, especially in urban areas. Buoyancy ventilation harnesses a natural flow from people, computers, photocopying units, lights, and whatever else, and uses that internal energy to drive a consistent flow of ventilation. This assures that you get the amount of fresh air that you need, but it can also regulate and balance temperature.
Temperature regulation is one of the biggest challenges facing architects and engineers working on building sustainable architecture today as escalating heat waves and cold snaps create skyrocketing energy use. This is, of course, a big part of your work. You’re interested, for instance, in moving building design away from its reliance on, say, HVAC systems. How did temperature regulation become your principal concern and how do you think it will affect the future of architectural design?
Having come into architecture and construction from left field and not having been trained in any one discipline, one of the things that became clearer and clearer to me is how siloed the knowledge disciplines were in a live project. When you look at the sort of technical organization of modern building systems, and modern building assemblies, it starts to be clear that they're a reflection of the fragmentation of knowledge in the field, rather than any technological epitome of evolution or progress. It’s understandable that the disciplines mostly work separately from each other, because they just need to get on with their work to get the building going.
For example, wood can do many things—structurally, thermally, hydroscopically. But currently, it's siloed, as a structural unit, right? So what we're looking at is that: how can something like wood do many things simultaneously, in order to radically simplify the bill of materials and all get rid the junk, frankly, that's occurring and hidden in buildings.
One of the buildings you’ve worked on—Colombia’s EDU headquarters in Medellin—had a particular relationship to its site. You took into consideration, for instance, what time new air flows come into the building, how and when hot air escapes, etc... In our climate change future, will the way that we design buildings have to allow for some change in human behavior? Will we have to change how we live? Will buildings have to change along with that?
It's a really important question, the feedback between behavior and use. I think there will be some consequences [for design] and incentives for certain behaviors and occupancy patterns embedded in the buildings. I think that's inevitable. One of the things I'm currently looking at is the idea of thermally nested spaces. Like there's a thermal onion that staggers down in temperature from an interior, to a semi interior, to the semi exterior, to exterior. So that you have a hierarchy of thermal energy, where in the winter some spaces are more centrally located and at the temperature that is comfortable in today's standards. And that could flip in, in the summer where it's cool in the center of the onion and it gets progressively layered out.
And that is a good way of distributing energy, but also for creating thermal texture throughout the space. So you're not just creating this harsh gradient between inside and outside and expecting the building to maintain that. But you can actually have scope for thermal experience and pleasure. The reason I'm interested in that from the experiential point of view, is for adapting to climate change, [because] we need to recalibrate our bodies to new conditions in a sort of layered way.
In an article for Massive Science called "Can Termites Teach Us to Build More Environmentally Friend Communities?,"—which I recommend reading—you argue that, should we can figure out the math and technology necessary to build more efficient ventilation technology en masse, we cannot assume that they will be immediately adopted or compatible with the way we've been living our lives thus far. You write:
“[U]nless we take the opportunity to rethink communal living and working, the effort could all go to waste. Who will tolerate temperature gradients inside their buildings? Atomized individuals, probably not, but hybrid communities, for whom activities are programmed according to thermal needs, perhaps. As cities grow and densify, big arcologies, for better or worse, become inevitable. Different patterns of living, working, and dwelling will have to be reconciled under shared roofs.”
I’m really interested in this idea of building denser cities. And, I wonder, what do you mean by “hybrid communities” and also what does it mean to “program” activities according to “thermal needs?” I guess I am wondering, given what you said in the termite article, where their mounds are constructed as if by centralized planning, but really by instinct, if you’re implying that we ought to start organizing our cities via some central plan? I guess I’m wondering what sort of politics you’re imagining.
I'm not advocating for central planning. No, I'm not advocating for that. An idea that we are exploring in the architecture studio is mixed-use developments—the idea that you can have a building, which houses many different kinds of occupancies and activities. And when you do that there are lots of interesting and new opportunities for communal interaction. There are also lots of opportunities for thermal recycling. Different areas and activities and zones will produce different levels of heat. If you bring a bunch of different programs or activities together, then you can have thermal sharing and cascading and thermal parasitic relationships between different parts, and [these different activities require] varied interior microclimates.
Your papers spend so much time talking about wood as a building material. How can we rely on wood in the future without devastating forests?
That’s the key question. We've won a grant to build a new research facility. And we've put together an interdisciplinary network spanning forest ecologists, to urban planners, to engineers, and architects, wood scientists and forest scientists, centered around [asking and answering] two core questions: The first is how can we harvest wood from managed forests in a way that increases the carbon sequestration of those forests safely and securely and reliably. Managed forests across Canada at the moment are, to give an example, our net emitters right, because of things like forest fires and bug outbreaks, etc... And so, there are questions of how—for want of a better word— to design forests in such a way that the ecological disturbance of the action actually invigorates tree growth and benefits ecology.
As you know, tree growth is asymptotic. Older trees sequester less and less carbon per year than the younger trees. That means we have to figure out something like: what are the sustainable rates for timber harvesting? The key balance is designing wood structures that last longer than the tree cycle. They have to last, say, 100 years and do multiple things at the same time. The buildings are not just providing structure but providing the thermal envelope to produce ventilation. If you can do this then, naturally, you could radically simplify architecture and building assemblies and move away from these multi-material, multi-layered assemblies, these layer cakes and cluster docks, and build templates that are more appropriate for regional approaches. So that they are more tied to a particular forest—coordinating the carbon exchanges between the forest and those building stocks.
I think that's quite handy information for the imaginary Planning Commission. Not to get us bogged down in that question again, but it does seem like we have to radically reimagine how we conceive planning at the level of the city and even the individual, in order to see any drastic changes in our carbon emissions.
We need to synchronize construction activities with forestry activities, and [this] needs to be regulated over a millennium. We need to understand the ecological limits of our forests. We know that if we continue to use concrete, steel, and glass in the way that we're using them—air conditioning in the way that we're using it—there's no way that we're going to tip the construction industry towards drawdown in the next few decades. Construction is responsible for 40% of global carbon emissions and 10% of that is concrete cement and steel. If we can use biomaterials, natural materials, that can store carbon and use those to not only substitute the basic structural materials, but to replace all the extra layers and added hidden products that saturate the construction industry, if we can engage a globalized supply chain—that, to me, is the only way that we can start to steer the construction industry towards drawdown.
Are you saying that in an ideal climate change world, people will stop building hideous all glass office buildings in the downtowns of every city?
Absolutely. Yeah, we can't do that. It's just not feasible anymore.
Do you imagine that these materials will merely cope with climate change, with the effects that are already happening? Or are they specifically meant to both cope with and ameliorate the effects of climate change?
Mitigate and adapt. So that, for example, the buildings are climate resilient and heat-wave resilient, and so that if there is a blackout people are going to die in that building, older people are not going to die, because it’s going to stay naturally cooler inside that building without the need for air conditioning. And it’s going to have lots of naturally generated ventilation so you’re not worried about passive pathogens. But then also, we need to think about buildings as an extension of the natural forest’s carbon sink.
Is prepping for each end of the spectrum—heat waves and cold snaps—related from a design point-of-view?
It can be and we'd like it to be. One thing we're looking at is this synchronization of thermal mass and buoyancy ventilation so buildings can work like termite mounds. We've developed these scaling rules where you choose your material and you define your free-running ventilation rate so you can design for that heat wave. The scaling rules tell you "oh you need this much surface area of that mass and that much thickness." And you can compare: if you want to do it with concrete, it will be such-and-such surface area and thickness, but if you want to do it with wood, you can make the same thermodynamics work, with the same performance, you just need maybe double the amount of material. If you get that right for the summer, you can tune it up so it works for you in winter. For example, when there's a blackout, it's not going cool down to the exterior temperature in half an hour, it's going to delay that state for a few hours, for half the day, or a full day.
What is something that you'd want someone who's interested in the connection between climate change, capitalism, and architecture to know?
[laughing] What can I say other than I think capitalism is defunct? And that we're killing the planet with it? And there has to be a stop to endless growth. I can't add a more learned perspective to that. I think that what I can comfortably say is that the way buildings are is the result of financial forces and supply chain forces, and the way that knowledge is fragmented across the industry. We're also going to have to explore the way buildings are programmed—that is to say, their uses. I do see an opportunity for mixed-use and multi-use buildings where we can have a kind of win-win, where they could, on the one hand, help cultivate meaningful community at a local level, and also share and recycle energetic and material resources in a way that is effective. Not in terms of rationing, just in terms of "hey you've got some spare heat over there, you've some spare cooling."
What do cities need to do differently, in 2050 or 2100, to deal with the effects of climate change?
I think the answer with cities is how to make best use of the infrastructure that's already there, and not build speculatively, because there's been a hell of an investment of embodied emissions in that infrastructure already.
I think there's a lot of focus on cities, but I think it's the more rural areas which hold the key. Everyone talks about 50% of the population being in cities but there's still 50% in rural areas, and there's going to be a lot of migration—from cities to rural areas, but across borders as well. If you take the example of forests: what we probably need are vertically integrated supply chains where the supplier of said integrated wood-based components are also implicated in the management of the forest. And those forests are located in local regions. Vertically integrating that supply chain; leveraging the local skills of communities to revitalize those economies—those are the kinds of templates we should be interested in, rather than trying to "solve cities."