Humanity has been on a carbon binge since the beginning of the industrial revolution. Our carbon binge began in the late 18th century, but usage skyrocketed post WWII. We fell in love with cheap, readily available fossil fuels, and never looked back. Thus, the carbon economy was born.
Energy use and carbon emissions walk hand in hand. Whether we measure our use and impacts in Energy Use Intensity (EUI) or metric tons of C02e, it all boils down to the fact that the release of carbon into the atmosphere results in pollution and global climate change. As a result, much of the world is calling to shift away from fossil fuels to a low-carbon, zero, or circular economy.
As energy codes and standards become more stringent, more states and local governments are calling for clean, net-zero (or better yet, net positive) energy buildings by 2035 and a complete decarbonization of the built environment by 2050. It turns out that may not be soon enough.
The 2015 Paris Climate Agreement calls for limiting the amount of global warming to 1.5c – or risk irrevocable change to the word’s climate. The Intergovernmental Panel on Climate Change (IPCC) reckons we have a 67% chance of meeting that goal – but only if we act immediately to enact a global carbon budget of 340 gigatons (GT) of C02e. At our current global emissions rate of 40 GT per year, we’re set to generate 1,200 GT of C02e by 2050 – far beyond our 340 GT budget. In fact, if our current rate of emissions proceeds unaltered, we stand to reach our 340 GT budget sometime in July of 2028. We need to make a change and make it fast.
Ed Mazria, FAIA, states that we need to cut emissions by 50% – 60% by 2030. He believes, however, that with the addition of incentives, policies, building upgrades and electrification, the building sector can achieve a 72% reduction by 2030 and reach zero emissions by 2040 – not quite 20 years from now. Doing it all at once may seem improbable, but we can’t get there if we don’t start.
What role does building design play?
For the most part, those of us in the design and construction industry have focused heavily on energy efficiency and operational carbon – reducing energy fossil fuel usage by reducing the amount of energy used in building operations while simultaneously moving toward renewable energy choices. It is easy to see the connection between operational energy use and carbon emissions and possible, though still challenging, to design buildings that operate on a net-zero or net positive basis. In fact, there are already hundreds of these buildings in existence today. Mead & Hunt designed its first net-zero energy building in 2013. The Appleton International Airport General Aviation Terminal was awarded LEED platinum certification and was designed to operate at net-zero energy and net-zero carbon standards by use of smart sustainable design strategies, ground source heat-pumps, the production of on-site renewable (solar pv) energy, and the purchase of certified renewable energy certificates and carbon offsets.
However, if we look only at operational carbon, we are missing a big slice of the carbon pie – embodied carbon. Embodied carbon is the summation of all the C02e emitted in the creation of a building – both the emissions directly resulting from the construction of the building, as well as those from the harvest, extraction, manufacturing, and transportation of its materials. Once a building is complete, its embodied energy (carbon) can never be decreased; its emissions have irreversibly entered the atmosphere. Ouch.
Between now and 2060, the world’s population will be doubling the amount of building floor-space, equivalent to building an entire New York City every month for 40 years. Much of the carbon footprint of these new buildings will take the form of embodied carbon and that embodied carbon will be responsible for nearly half of total new construction emissions between now and 2050.
In the next 30 years, the embodied carbon emissions from a highly efficient building may represent 75% or more of its total carbon emissions. As our operational energy becomes more efficient, embodied energy and carbon emissions carry more weight. Between now and 2050, embodied carbon will be the driving force of carbon emissions from buildings.
What does this mean for us in the AEC industry?
In our quest to achieve zero carbon by 2050, we can no longer measure a building’s total carbon impacts based on a building’s full potential lifespan of 60-100 years. We only have 20-30 years to get there. Is it possible to make significant reductions in the next few years? The Carbon Leadership Forum thinks so. They recently completed a four-month research project with a major US tech company to understand the potential of using low-carbon and carbon-storing materials in new construction. The study found that a sizable reduction (~60%) in embodied carbon is possible in as little as two to three years by bringing readily available low-carbon materials into wider use. Furthermore, this work predicts that individual projects can be carbon-positive within three to five years through fostering a carbon-storing material supply system by investing in the development and manufacturing of nascent carbon-storing materials industries.
We need to act today. We can’t meet our climate goals without phasing out both operational and embodied carbon emissions. Here are a few things we in the design and construction industry can do to make this change.
- Count the Carbon. We can reduce or eliminate operational emissions with upgrades, but embodied carbon emissions can’t be reversed. We need to set embodied and operational performance targets and achieve them, measuring our performance as we go. There are plenty of tools to help us benchmark, baseline, and track our carbon emissions.
- Perform Whole Building Life Cycle Assessments (WBLCA) on all projects looking at components and assemblies in both isolation and bundles to reduce a building’s total carbon emissions.
- Collaborate with our peers and partners using an integrative systems design approach in our work. Everything about a building’s design and performance is connected.
- Maximize the use of existing buildings wherever possible in lieu of all new construction.
- Design buildings to meet Net Zero Energy and Net Zero Carbon standards.
- Design buildings to be resilient, flexible, and adaptable for future uses.
- Maximize the use of salvaged materials, or materials with high recycled content.
- Find low carbon alternatives in the manufacturing of concrete, steel, and other building materials as we optimize their use.
- Use local and bio-based materials, and select Carbon-Storing Materials.
- Select carbon-smart materials with longevity and durability appropriate to a building’s proposed life span.
- Plan for the end of a product’s life cycle, design for recycling, re-use and/or disassembly of a building and its components.
- Demand change from our industry partners, manufacturers, and producers.
As planners, architects, and engineers in the design and construction industry, we are uniquely positioned to affect positive change in our industry. There are many resources and tools architects can use to help in this process:
- Architecture 2030 Carbon Smart Materials Palette. The 2030 Palette is a free online platform that curates information and practices to provide guiding principles for creating low-carbon buildings.
- Athena Sustainable Materials Institute’s Impact Estimator for Buildings. A free LCA-based software package that lets architects, engineers, and analysts explore the carbon footprints of different material and system options.
- Beacon. An open-source Revit plug-in for structural engineers that generates a data visualization of a project’s embodied carbon, Beacon presents the embodied carbon by material type, building element, and floor levels, allowing engineers to know where to minimize it.
- EC3 by Building Transparency. The Embodied Carbon in Construction Calculator (EC3) is a free tool that enables architects to find and compare products in order to source low-carbon options available for purchase in their region. It also lets them plan and compare buildings by entering project material quantities to benchmark, set, and realize project-specific embodied carbon reduction targets.
- ECOM – Embodied Carbon Estimator. An embodied carbon estimator that quickly determines the embodied carbon order of magnitude of a material product, framing assembly, or an entire structural frame.
We know that responsible, sustainable design reduces energy use and eliminates dependence on non-renewable fossil fuel resources while improving building performance and function, as well as human comfort, health, and enjoyment. It’s our responsibility to lead the construction industry in the global fight against climate change.