In the effort to halt and reverse climate change, the embodied carbon of building materials matters more than anyone had thought. We are in technological reach, within a generation, of creating buildings and cities that generate more energy than they use, reverse the emissions engine, cool the climate and make nicer places to live and work.
By Bruce King
Imagine … you walk into a brand-new building and immediately sense that something is different. The structure is made entirely of exposed wood – the columns, beams, and roof are great curving slabs of timber elegantly joined together. The skin and insulation – which you can also see – are straw, bound into shapes that shield from the rain and insulate the walls. The foundation is soil from the site transformed by invisible microbes into a strong concrete that holds everything up; on top of this are warm, leatherlike floors that need no covering.
You think to yourself that it should look and smell like a barn, yet somehow it feels more like an inviting bedroom, or even a museum. It’s nicer than any building you’ve ever been in before – but it’s not a hand-built house in the woods. It’s a new downtown office building, nine stories high, full of people and filling half a city block. It gathers all the power and water it needs from the sky, it is elegantly lit by daylight, and it processes all its own water and waste into soil for the courtyard gardens. And, though you can’t see it, its construction put thousands of tons less carbon into the air than structures built a decade earlier, and even pulled hundreds more out of the air to serve as the walls, floors, and roof.
But to back-up a bit … we’ve been developing the art of building since the dawn of the agricultural revolution 8,000 years ago. That extended worldwide moment was arguably the most disruptive in history – for us and the rest of life on Earth. Rather than hunt and forage for our food, we grew it in one spot, and next thing you know we had architecture, political states, wealth and poverty, global tension, and Wi-Fi-enabled drive-thru hamburger stands everywhere. However, for the last few centuries we’ve also been learning through science. We now know an awful lot more about how things work than we ever did before, but we can also dimly see how much we still don’t know.
In many ways, the history of architecture follows the development of materials — follows the history of people messing around with things found in the landscape to create bricks, then boards, then toilets, then building-integrated photovoltaic panels. Two hundred years ago engineers in England placed iron bars in the newly invented Portland cement concrete, and architects went wild: the result was every downtown skyline in the world, with lights, plumbing, and comfort hundreds of feet in the air. It seemed like the party would never stop, but the hidden costs are arriving and starting to hurt.
Building materials account for 9-15% of global emissions, so we have to change not just the way we build, but what we build with. For the past century, it has been increasingly easy and cheap to extract, process, assemble, and transport everything we use in building. Every modern industrial society has codified systems, laws, and standards of construction that are based on abundant fossil fuels and having an “away” where we can throw things – and which even inhibit and penalize those who seek better ways to build. But it won’t last for much longer: the “heat, beat, and treat” approach to making and processing materials is killing us, as is the notion that we can throw away anything into landfills, water, soil, or the air.
Introducing the new carbon architecture: Buildings made of sky
The built environment can switch from being a problem to a solution. For the first time in history, we can build pretty much anything out of carbon coaxed from the air. This includes mid-rise buildings almost entirely fabricated from wood with just the ground floor and central core made from concrete; prefabricated mass timber buildings with integrated straw insulation; insulation, wall coverings, and even concrete substitutes from mushrooms and bacteria; as well as “hempcrete” that uses a hemp/mineral mix and acts as concrete and insulation.
We are in technological reach, within a generation, of creating buildings and cities that generate more energy than they use, reverse the emissions engine, cool the climate, and make nicer places to live and work. It’s time to bring the carbon home.
This text is based on the paper Building to cool the climate: The new carbon architecture, which was an excerpt from The New Carbon Architecture (Gabriola: New Society Publishers, 2007).The paper was presented by Bruce King at the LafargeHolcim Forum “Re-materializing Construction” held at the American University in Cairo, Egypt.
Inspired by the discussions by 350 leading thinkers from architecture, engineering, planning, and the construction industry from 55 countries, Ruby Press Berlin has published The Materials Book that evaluates current architectural practices and models, and introduces materials and methods to maximize the environmental, social, and economic performance of the built environment in the context of “Re-materializing Construction”.