For the past eight years, I’ve spent every day of my professional life enabling an industry that is responsible for nearly 40% of global climate emissions. I don’t work for an oil or gas company. I don’t work for an airline. I’m an architect.
The environmental impacts of the built environment are staggering. Although it’s become mainstream to discuss energy efficiency and advocate for minimizing those impacts, architects, engineers, and planners have yet to truly reckon with the magnitude and consequences of everyday design decisions. Not only do we burn fossil fuels to heat and cool most buildings, but construction itself is responsible for plenty of global emissions. Construction requires massive amounts of concrete, steel, aluminum, and glass—all of which are carbon-intensive materials. Their emissions extend up and down the supply chain, crossing property boundaries, economic sectors, and markets. While architects are not fully responsible for steel manufacturing or concrete production per se, there is a direct line from the material specifications that architects write to the steel mills of China, the coal mines of Appalachia, the brick kilns of India, or clear-cut forests in the Pacific Northwest or the Amazon.
It is time for the design community to come to terms with carbon and climate change—both the reality of our shared climate emergency and the very personal implications of the building industry’s role in perpetuating it. Only then can we do the hard work of connecting our climate concern with our day-to-day actions, transforming guilt into collective change.
FOCUS ON CARBON
Broadly speaking, there are two ways of measuring the emissions caused by buildings: operational carbon (the emissions associated with energy used to operate a building) and embodied carbon (the emissions associated with materials and construction processes throughout the whole life cycle of a building).
Programs such as LEED, Passive House, and the Living Building Challenge focus on decreasing the former—operational carbon. This is a laudable goal; after all, building operations account for 28% of global carbon emissions, and improving the energy efficiency of buildings through widespread electrification and through decarbonization of the energy grid is essential.
However, we’ve come to recognize that it is not enough for architects and engineers to focus solely on operational carbon. For decades, we have been ignoring the role of embodied emissions in global carbon budgets.
Embodied carbon from building materials and construction currently represents at least 11% of global carbon emissions, much of which can be attributed to just three materials: concrete, iron, and steel. However, that seemingly small slice of the full carbon pie can be misleading. Global construction is proceeding at an incredible pace—with roughly 6.13 billion square feet of construction each year and global building stock expected to double in the next 30 years. When we look at new buildings anticipated to be built between now and 2050, embodied carbon, also known as “upfront carbon” because it is released before a building is even occupied, is projected to account for nearly half of total new construction emissions. For practicing architects, engineers, policymakers, and anyone who cares about climate strategy, this should give us pause.