Carbon has become a dirty word. Discharged from smokestacks and tailpipes, the excess carbon in our atmosphere is now undermining the climate stability of our planet. Yet we know from Chemistry 101 how valuable carbon is. As the fourth most common element in the universe, this inherently versatile substance is one of the key components of all life. In fact, carbon is the next most abundant elemental ingredient in our own body, after oxygen.
The problem with carbon is not its existence, but our mishandling of it. This realization is the primary focus of the book The New Carbon Architecture: Building to Cool the Climate (New Society Publishers, 2017), edited by Bruce King, engineer and founder of the San Rafael, Cailf.–based Ecological Building Network. In this timely work, King and a collection of environmental experts evaluate our mismanagement of this key element while providing stimulating examples of solutions to our carbon conundrum. For the authors, the new carbon architecture represents something entirely aspirational—what they call buildings “made of sky.” Rather than avoid carbon, they recommend that the AEC industry embrace the element.
Erin McDade, program manager of the nonprofit Architecture 2030, explains this welcoming outlook by arguing that buildings are the problem, but also the solution. For most buildings, carbon emissions related to their lifetime operation far outweigh those related to their construction, also known as embodied carbon. Yet the clock is ticking. Carbon dioxide emissions must be curtailed by 2050 to avoid the maximum global temperature increase threshold of 35.6 F. Because this deadline is quickly approaching, “the timeline is much shorter and the relative importance of embodied carbon changes,” McDade writes. In fact, the closer we get to 2050, the more significant embodied carbon becomes, since new buildings will have less time to operate by then. “Assuming a building is constructed today and operates 50 percent more efficiently than a typical building, by 2050 only 45 percent of the energy consumed by that building will have been used for operations, meaning that 55 percent of that building’s total energy consumption is embodied energy,” she adds. Thus, the focus is shifting from operating efficiency to material efficiency.
But what about buildings made of sky? Such a shift must invariably include the choice of carbon-storing materials rather than those whose manufacture is responsible for emitting carbon dioxide. Arup engineers Frances Yang and Andrew Lawrence present the case for using timber as a structural material—an increasingly popular choice in the U.S. and abroad. While it is commonly known that wood is a more ecologically responsible material than steel or concrete, the authors detail the disparities using a study Arup conducted on a 12-story mixed-use project in Portland, Ore. Demonstrating that timber has a mitigating effect on global warming not only during its life as part of a tree but also throughout the lifespan of a building it supports, Yang and Lawrence reveal wood’s vast superiority over a similar design in concrete.
Sustainable materials specialists Chris Magwood and Massey Burke turn our focus to the “other carbon-capturing ‘forests’ that have so far escaped much attention—the vast miniature forests where we grow our food.” The authors note that we grow some 720 million hectares of cereal grains annually for their seeds; meanwhile, “supporting every nutritious seed head is a tubular stalk that is essentially a little tree.” These stalks, otherwise known as straw, can provide an important carbon-sequestering function in building materials such as straw bales, insulating straw blocks, straw panels, and plant fiber insulation systems.
One common material that requires significant improvements for the purposes of making new carbon architecture is concrete, the most widespread building material on Earth. The energy intensity of Portland cement, which results in one ton of carbon emitted for every ton of material produced, has made the ingredient a prime target for elimination in concrete mixes. According to engineers Fernando Martirena and Paul Jaquin, embodied carbon is only one of two fundamental challenges with today’s concrete. The second problem is that “there’s not enough cement-making capacity in the world to take care of the next three billion people due in the next 15 or so years.” Instead, the authors encourage the use of alternative earthen materials including rammed earth, adobe, and cob.
Another problem substance is plastic—specifically the traditional petroleum-based variety. Despite petroplastic’s many benefits, the substance is inherently flawed. Made from abiotic carbon—the non-biogenic variety—petrochemical polymers are composed of carbon “that is nonrenewable on a human time scale.” This would not be such a problem were it not for petroplastics’ unintended yet ubiquitous persistence in the world’s oceans. According to the New Plastics Economy initiative, “by 2050 the amount of plastics in the world’s oceans from dumping and runoff could exceed the weight of all the fish in the seas.” Although there are no easy solutions, the authors point to improved recovery and recycling, nontoxic varieties, and biopolymer alternatives for petroleum-derived plastics.
In addition to material topics, The New Carbon Architecture addresses several other building design and construction-related issues. Larry Strain, FAIA, principal of Siegel & Strain Architects in Emeryville, Calif., focuses on the fundamental advantages of adaptive reuse over raze-and-rebuild strategies. Green design consultant Ann Edminster evaluates the topic of size, asking the loaded question “Can buildings be too tall?”
For all the useful and inspiring information in The New Carbon Architecture, King admits that the book could have been much longer, claiming that “to make for a simple read, we chose to barely touch on a great many subjects… that each call for more notice, if not an entire book, to themselves.” Perhaps the most intriguing omission is not subject matter depth per se, but rather the focus of the title—architecture. Although the authors mention a few specific buildings, the text otherwise prioritizes material technologies, life cycle assessment, industrial processes, climate agreements, and cultural norms. The reader seeking stimulating architectural case studies or in-depth building methods will be disappointed. Rather, the authors provide a variety of concise, well-researched arguments that set the stage for a new carbon architecture without actually describing what it is—like narrators establishing the scene for an absent protagonist.
Perhaps this exclusion is for the best, as it invites one’s imagination to roam freely. Architects who venture to peruse The New Carbon Architecture will, therefore, have to conceive their own buildings made of sky.
