Embodied carbon is the silent threat in buildings because it represents the hidden environmental impact of a structure, encompassing emissions from material production, construction, and disposal. It’s often overshadowed by operational carbon, but its cumulative effect on climate change and resource depletion is substantial. This threat lies concealed in the building’s structure and lifecycle, making it essential for design professionals to address this often-overlooked aspect of sustainability.

According to the EPA, since the Industrial Revolution, human activities have released large amounts of carbon dioxide and other greenhouse gases into the atmosphere, which has changed the earth’s climate. Natural processes, such as changes in the sun’s energy and volcanic eruptions, also affect the earth’s climate. However, they do not explain the warming that we have observed over the last century.

Concentrations of the key greenhouse gases have all increased since the Industrial Revolution due to human activities. Carbon dioxide, methane, and nitrous oxide concentrations are now more abundant in the earth’s atmosphere than any time in the last 800,000 years. These greenhouse gas emissions have increased the greenhouse effect and caused the earth’s surface temperature to rise.

Driving Action on Embodied Carbon in Buildings

In September 2023, the USGBC and the Rocky Mountain Institute released the report, Driving Action on Embodied Carbon in Buildings. Today we will highlight important insights from this report and then pinpoint LEED strategies that can help reduce embodied carbon in buildings. The two organizations draw from a comprehensive foundation of research based on the most up-to-date and relevant data and industry knowledge to establish a set of recommendations and actions for embodied carbon, including:

• The state of the data on embodied carbon
• The opportunity to reduce embodied carbon from standard building practices
• Current and emerging benchmarking standards
• The carbon intensity of specific materials
• Embodied carbon savings potential from reuse, recycling and circularity
• Assessments of emerging and future low-embodied-carbon technologies

Simply meeting the energy needs to run — heat, cool, light, and operate — the world’s building stock accounts for about 30 percent of annual energy-related emissions, according to the IEA. Yet that figure doesn’t capture the full climate footprint of buildings. Manufacturing, transporting, installing, maintaining and, finally, disposing of the steel, cement, cladding, coatings, and other diverse materials needed to build new construction adds to the sector’s toll. Embodied carbon alone accounts for 11 percent of global annual energy-related emissions, the World Green Building Council estimates. Given the scale of the sector’s climate impact, it is imperative that owners, designers, builders, manufacturers, and policymakers lead the market by prioritizing this issue. As our understanding of embodied carbon has steadily increased, so has the urgency of reducing all carbon emissions.

A Call to Action

Successful decarbonization requires collective industry action from multiple players. We must expand industry knowledge of current best practices for low-embodied carbon buildings through programs, initiatives, and certifications. Manufacturers must publish more EPDs and develop low-embodied carbon building products. Leading designers must demonstrate effective low-embodied carbon building design strategies and share best practices. Developers must consider lower-carbon options, including adaptive reuse. Governments must prepare the way for embodied carbon regulation by investing in low-embodied- carbon public buildings and supporting research and market development of low-embodied carbon building products and practices, including incentivizing the circular economy through building reuse and deconstruction ordinances.

Unfortunately, operational reduction efforts alone will not be enough to meet climate targets. By mid- century, we must achieve zero emissions from all aspects of buildings, including embodied carbon. As we become more successful at addressing operational emissions, embodied carbon will become an increasing piece of a shrinking pie. Meeting global climate targets requires that today’s buildings are designed for both low embodied and operating emissions. This will require the advancement of action on embodied carbon comparable to the level of ambition in current and developing energy efficiency regulations, including the advancement of product manufacturing and design-team education.

The USGBC and RMI report recommend the following:

• Include experts on both operational and embodied carbon on all project teams.
• Iterate on both embodied and operational carbon scenarios to understand how to incorporate the win-win scenarios
• Look to emerging standards such as ASHRAE/ICC 240 and programs such as LEED on how to better address embodied and operational carbon to maximize holistic emissions reductions.
• Actively support the advancement of impactful embodied carbon regulation toward the level of ambition current in energy efficiency regulations, energy efficient product manufacturing, and design team knowledge of energy conservation and efficiency.

In conclusion, the imperative for design professionals to actively contribute to the fight against climate change by making conscious choices to reduce embodied carbon in building design cannot be overstated. Your role in this endeavor is pivotal, as each decision you make carries long-lasting consequences for our environment and the well-being of future generations. By opting for materials with lower carbon footprints and embracing sustainable practices, you not only shape the physical landscape of our world but also play a vital role in shaping a more sustainable and resilient future.

The collective power of design professionals to drive change through optimized product specification is a cornerstone in our efforts to combat climate change, mitigate its effects, and pave the way for a greener, healthier planet that benefits us all. Your actions today will leave a legacy of responsible stewardship for generations to come, making your commitment to reducing embodied carbon an essential component of the broader climate change solution. Design professionals interested in learning more about this topic can participate in the course Embodied Carbon: Unmasking the Silent Threat.