A response to William McDonough’s new language of carbon.

“We’re made of star stuff.” Carl Sagan

“We are stardust.” Joni Mitchell

Carl and Joni got it right. So does William McDonough when he says that carbon is not the enemy (“Carbon is Not the Enemy,” in the journal Nature in November and referenced in Blaire Brownell’s “William McDonough Reconsiders Carbon and Its Misuse,” in Architect the same month). Carbon is, after all, a basic component of all life on this planet. His “new language of carbon”—distinguishing between fugitive, durable, and living carbon—challenges us to rethink what carbon is and how we might work with it differently. McDonough correctly points out that carbon negative is a positive and we should start calling it that. (Fugitive is an interesting word choice for unwanted carbon. The first definition of fugitive—“a person or thing that has escaped”—makes sense. The second definition—“fleeting and quick to disappear”—is, unfortunately, not the case for atmospheric “fugitive” carbon.)

He is also correct to call out carbon offsets. We need to plant trees and convert fugitive carbon to living and durable carbon, but not as a justification to continue making more fugitive carbon. Finally, he sets the bar at the top: “Just stop it. Don’t offset it. Carbon dioxide in the atmosphere is like lead in a river, right? You don’t put lead in rivers. You don’t start saying, ‘I’m going to reduce my lead in the river by 20 percent.’ You stop it.

New buildings, he says, should all aspire to bring forth “a delightfully diverse, safe, healthy and just world with clean air, water, soil and power.” Who wouldn’t want that? Architects have made progress, but we still fall short of this goal and thinking only about new buildings is part of the problem.

We cannot build our way out of the global warming crisis by relying only on new cutting-edge green buildings. Most of the emissions from the built environment come from operating existing buildings, so one important strategy is to upgrade and reuse existing buildings—and build fewer new buildings. Reuse recycles the durable carbon that is tied up in building materials and reduces the need for constructing new buildings and manufacturing of new materials with their associated fugitive emissions. Efficiency upgrades, powered by renewables, reduce fugitive carbon emissions from operating our existing and inefficient buildings.

Another important strategy is reducing embodied carbon—the carbon dioxide emitted during the manufacture, transport, and assembly of building materials. Carbon emissions have a time value; embodied carbon is front end loaded: It ends when the building is occupied (except for upkeep), while operating energy starts with occupancy and continues at a steady rate throughout the life of the building. As buildings use less and less energy to operate, carbon emissions embodied in building materials and construction become a larger part of the fugitive carbon equation. Over the next 20 years—the critical period for reducing the adverse effects of climate change—embodied carbon will be responsible for most new building emissions.

The built environment is, as we all know by now, responsible for 40 to 50 percent of “fugitive” carbon emissions. What’s missing in McDonough’s redefinition is the sense of urgency required to really act on climate change, since we are on track to hit a global tipping point in the next 10 to 20 years. Given that timeline, we need to do everything we can. Actually, less bad is good.

We can’t wait for the economy to be reinvented. We don’t have a century to get to carbon positive. We need large reductions in carbon emissions now. By all means, let’s encourage and hasten transformational, paradigm-shifting change. But we also need incremental, obvious, “we already know how to do this,” change right now.

The featured image is Siegel & Strain’s work for Bishop O’Dowd High School in Oakland, CA. The Center for Environmental Studies is a net zero energy project. The photo was taken by David Wakely.

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