Embodied Carbon and Operational Carbon
The Climate Impact of Our Buildings.
There is a particular urgency regarding the climate impact of our buildings. At the time of this writing, 97% of the science community has come to consensus about the fact that anthropogenic (human-caused) greenhouse gas emissions will lead to irreversible climate disruption if dramatic reductions are not realized within the first few decades of this century.
In order to address this emergency, Architecture 2030, a leader in the climate action movement in the building industry, has called for zero carbon emissions by 2050 for all new construction.
This includes both operational carbon, which is the carbon load created by the use of energy to heat and power a building, as well as embodied carbon, which is the carbon that is released in the manufacturing, production, and transportation of our building materials.
For the decades that the building community has been working on improving energy efficiency, the strategy has been to use relatively high-embodied carbon materials, such as insulation, to offset long-term operational carbon loads, which over the life of the building are considerably greater (especially for conventional buildings). However, this is changing rapidly, and the building community must now take the consideration of embodied carbon very seriously, for the following reasons:
- Within the short time frame we have to reduce impacts, using high-embodied-carbon insulation to reach high levels of building energy performance, especially spray and board foam, may not save enough energy to justify its use (as compared to building a lower-performance building). No longer can we “front-load” 20 or 30 years’ worth of operational carbon into the construction of our buildings and wait for the long-term reductions to kick in — we need immediate reductions, which must come from the construction phase, particularly in material selection.
- As we build buildings with lower and lower operational loads, a higher percentage of our carbon impact is in our materials. We know how to improve energy efficiency, but we must focus on how to do it using lower-carbon materials and practices. “Net Zero” and other approaches using renewable energy to offset operational carbon does nothing to offset our embodied carbon!
- We now have the technology to measure, evaluate, and effectively use low-carbon materials to build high-performance houses. Many of these materials are some of the oldest materials we’ve built with — wood, clay, stone, straw. We now have the experience, scientific understanding, testing and evaluation technology, and modeling software and datasets to put these materials into a modern context.
- Rather than a future vision, the low-carbon high-performance home is both a practical reality and an urgent need. When setting your values, goals, and strategies, we encourage you to hold climate action as a value, zero-carbon building as a goal, and using low-carbon materials as a strategy!