The Silent Threat: Embodied Carbon

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.

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How To Reduce Carbon

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

Building decarbonization requires collective industry action: Forerunners are already demonstrating what is possible, but we need more leaders to push the boundaries to scale up swift and deep decarbonization. The industry is poised to make this leap, and there are substantial emissions reductions available today that are well within reach. Tools and guidance are widely available, low-hanging fruit have been identified, and new policies are creating greater market certainty. It is time for everyone to get on board to reduce embodied carbon.

When we talk about embodied carbon, we’re talking about the greenhouse gas emissions associated with materials and construction processes throughout the whole lifecycle of a building, including raw material extraction, manufacturing and processing, transportation, installation, maintenance, repair, replacement, and waste processing. When we talk about global warming potential, we are describing a metric of greenhouse gas emissions impact measured relative to the impact of one molecule of carbon dioxide, usually over a 100-year timeframe.

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EPD Impact Categories

There are six impact categories within a Life Cycle Assessment or Environmental Product Declaration (EPD) that design professionals will need to consider when selecting products based on their goals. They include:

? GWP - Global warming potential. This relates to all CO2 and greenhouse gas emissions during the production and use of a product.

? Depletion of the stratospheric ozone layer. This is when ozone-depleting gases like CFCs, HCFCs and halons cause damage to the ozone layer.

? Acidification of land and water sources. Acidic gases such as Sulphur dioxide react with water in the atmosphere, leading to the formation of acid rain.

? Eutrophication. This is when certain levels of nitrates and/or phosphates in water can eventually lead to harmful algal blooms, dead zones, and fish deaths.

? Formation of tropospheric ozone. This relates to when nitrogen oxides and VOCs form ozone and other air pollutants in low levels of the atmosphere, causing smog.

? Depletion of nonrenewable energy resources such as fossil fuels.

So, lets return to the USGBC and RMI report to better understand some of the key takeaways. How big an opportunity is embodied carbon? Up-front embodied carbon emissions from building construction in the United States is estimated at up to 370 million tons of CO2e annually, or about 6% of total US GHG emissions per year.

This long-invisible source of emissions is large, ?comparable to all of California’s current annual emissions. Embodied carbon from less studied elements like mechanical equipment and tenant improvements would likely increase this percentage. At these levels, even small reductions in embodied emissions could prevent millions of tons of CO2 emissions each year.

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Which Should We Prioritize?

We can and must reduce both operational and embodied carbon emissions in the next decades to avoid the worst effects of climate change. It is possible to achieve excellent climate performance in both embodied and operational emissions without pitting one against the other. Most embodied carbon is emitted up front during the manufacturing and construction of products and buildings and has an outsize climate impact in the first decade of a new building.

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.

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Design Strategies and Carbon

?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.

? Use the embodied carbon hierarchy of design interventions to consider the range of possible interventions to reduce embodied carbon, starting with considering reuse over new construction and using less material overall (dematerialization).

? Specify low-embodied-carbon materials where possible while weighing durability, reusability, recyclability, and impacts to other building systems to achieve the best whole-life outcome.

? Seek to use an integrated process like building-level LCA to identify strategies that minimize embodied carbon emissions holistically.

? Work with local or regional green building councils and professional groups to encourage local markets to develop more low-embodied-carbon materials locally and EPDs.

? Attempt to use at least one advanced carbon-storing or carbon-negative material on every project, even if just as a demonstration.

We highly recommend that design professionals review the report Driving Action on Embodied Carbon in Buildings. We thank the USGBC and RMI authors involved for creating such an outstanding work on a complex subject that they helped to transform into an approachable subject. The report breaks down complex ideas into manageable and easily digestible components for design professionals. We recognize the countless hours, research, and dedication you poured into this project, and we want to express our gratitude for your relentless pursuit of excellence. Design professionals can download this report for free at the USGBC website.

Download Free Report: https://shorturl.at/bkuEV

HPDs, Declare Labels, and LEED Documentation: https://elixirenvironmental.com

?About the author: Brad Blank has worked with building product manufacturers, architects, engineers, and specifiers for over fifteen years. Having made architectural specification calls for numerous building product manufacturers, Brad understands first-hand the importance of being able to offer proof of a product's sustainability claims. He obtained his M.F.A. from the University of Miami graduate film program. After working as a producer, writer, and director in the motion picture industry in Los Angeles, Brad turned his attention to the education market. As Media Director for GreenCE, Brad has created several video continuing education courses on topics such as Net Zero Energy Building Certification? (NZEB), LEED Platinum schools, and Health Product Declarations (HPDs). He oversees our video services which include: concept & development, script writing, production, and post-production.