Embodied Carbon: The Blindspot of the Buildings Industry

Between now and 2060, the buildings industry is poised to add a whopping 230 billion square metres of new construction worldwide. That means we will double the amount of buildings we currently have on the planet over the next four decades. To put this into perspective, we are constructing the equivalent of an entire New York City every month for the next 40 years. Let that sink in.

Given the sheer volume and speed of new construction, it is critical that we design all of these buildings as sustainably as possible. But what do we mean when we say sustainable? When you hear the term “green buildings”, what comes to mind? If you are like most people, you think about energy efficient buildings that use renewable energy. That is no coincidence, since reducing operational energy use has been the primary focus of green building efforts for decades. Passive House and Net Zero Energy buildings are great examples of how we can design buildings to make significant reductions in operational energy use.

Of course, it’s undeniable that reducing carbon emissions from operational energy use is extremely important and should be a key priority. But our industry’s single-minded focus on operational energy efficiency raises  the question: What about the greenhouse gases emitted during the construction of all these new buildings? If we really are adding another New York City to the mix every month, why aren’t we thinking about the environmental impacts associated with the materials used to construct those buildings?

Well, actually, we are—or at least, we’re starting to. With promising policy initiatives and a rapidly growing awareness surrounding the concept of embodied carbon, the green building industry is now beginning to understand and take steps toward reducing the enormous environmental impacts associated with construction materials. Today, there is a small but growing group of impassioned individuals, organizations and policymakers tackling the problem of embodied carbon. But it is nowhere near enough.

For all of us dedicated to building an industry genuinely invested in the future of our global climate, it’s a concept that needs to become a priority—and now.

What is Embodied Carbon?

Buckminster Fuller once famously asked Norman Foster, “How much does your building weigh?” How about today’s buildings? Where did all of that concrete, steel and wood come from? What did it take to extract, manufacture and transport those materials? What will happen to them when your building eventually gets torn down?

The term “embodied carbon” refers to the carbon footprint associated with building materials, from cradle to grave. Using the scientific method known as Life Cycle Assessment (LCA), we can quantify the environmental impacts associated with all of the construction materials used over a building’s lifespan.

Unlike your building’s operational energy use, which is more visible and easier to measure, these “embodied” environmental impacts are hidden and often overlooked. Though conventional wisdom focuses on operational carbon emissions as far exceeding those of embodied carbon, the building industry is now realizing that we have underestimated the importance of embodied carbon.

Why Does Embodied Carbon Matter?

According to data from the UN Environment – Global Status Report 2018, the buildings sector is responsible for a full 39% of global energy-related carbon emissions. While it’s true that the majority of these emissions—around 28%—arise from the day-to-day operations of existing buildings, the other 11% come directly from the embodied emissions of constructing new buildings. That 11% slice of the pie is what the buildings industry has mostly ignored—our industry’s blindspot.

(Source: Architecture 2030)

“Embodied carbon will be responsible for almost half of total new construction emissions between now and 2050.” – Architecture 2030

This puts embodied carbon on par with operational carbon emissions over the span of the next three decades. So if you are designing green buildings with the idea that you are saving the planet, but you don’t consider embodied carbon, you are missing half of the equation.

(Source: Architecture 2030)

It should be noted that this statistic does not account for the full lifespan of these new buildings, but rather only looks at the operational and embodied emissions that take place between now and 2050. If, instead, we look at a typical building over a 60 year lifespan, we see that embodied carbon generally makes up between 10% to 70% of its impacts, depending in large part on the carbon intensity of the local energy system.

(Source: Architecture 2030)

One thing that is often not discussed is the time value of carbon. While it is important to look at cumulative emissions over the lifetime of a building, it also matters when these emissions take place. Once a building has been constructed, the embodied carbon has already been emitted, and the emissions will actively impact our climate for the next decades and centuries. You can’t do anything to reduce embodied carbon once a building has been built. The same is not true for operational carbon emissions, which could be reduced in the future by scaling up renewable energy generation in the grid, and by retrofitting buildings.

The Climate Implications

The importance of embodied carbon becomes even more evident when you consider that, according to the IPCC, to limit global warming to 1.5°C, carbon emissions would need to peak next year in 2020 and then go to net zero globally by 2050. Given that embodied carbon will make up almost half of total new construction emissions between now and 2050, we cannot ignore embodied carbon if we want to have any chance of hitting our climate targets.

(Source: IPCC SR15 SPM)

As disturbing as the IPCC’s recent report may be, it doesn’t even factor in potential climate tipping points, which could be triggered by passing certain thresholds of warming. While there is significant uncertainty in this field of research, a recent Guardian article cited a study that explored the potential risk where crossing 2°C of warming could lead to a domino-like series of cascading, self-reinforcing feedback loops that prevent the climate from stabilizing, leading to a “Hothouse Earth”.

(Source: Steffen, W. et al., 2018)

This further emphasizes the importance of reducing near-term emissions, as doing so can give us slightly more time to decarbonize our grid and reduce future operational energy use emissions. Put simply, if we don’t reduce emissions now and end up triggering some tipping points as a result, it may not matter how energy efficient our buildings are 60 years from now.

We are already experiencing many of the effects of climate change, including increased risks of wildfire. In British Columbia, where I live and work, the wildfires we had over the past two years were the largest on record. Each is estimated to have emitted two to three times the carbon emissions of the province’s  annual fossil fuel use across all sectors. The unprecedented wildfires in California caused immense damage and forced PG&E, the largest utility in America, to declare bankruptcy. As the brave 16-year-old Greta Thunberg said in her powerful talk in Davos, “I want you to act as if the house was on fire, because it is”.

All of this paints a picture of why we urgently need to focus on embodied carbon. Luckily, the long-neglected idea of embodied carbon is finally gaining traction, and policymakers and industry leaders are taking note.

Policies and Certifications

There are already numerous regulatory bodies focusing on the impact of embodied carbon. The Embodied Carbon Review study conducted by Bionova recently reviewed over 100 certifications, regulations, and voluntary incentive systems addressing embodied carbon around the world. Over the past five years, the number of these systems has more than doubled. Such regulations and incentives are the primary reason why our industry is finally starting to pay attention to embodied carbon. For us to adequately address embodied carbon, we need to rapidly scale up the number of embodied carbon policies around the world, and also increase the requirements and thresholds for carbon reduction.

(Source: Embodied Carbon Review)

In North America, one of the major industry drivers for addressing embodied carbon is the LEED green building rating system. Since the release of LEED v4, projects have been able to achieve up to five LEED points through the use of Whole Building LCA. Now with the LEED v4.1 update, some changes have been made to the LCA credit, with the aim of increasing uptake of this credit and incentivizing further reductions in embodied carbon to 20%, up from the previous 10%.

Here in Vancouver, our city council has recently approved what I believe is the most ambitious embodied carbon target in North America. This target is one of the six “big moves” from the city’s Climate Emergency Response. It states that by 2030, the embodied emissions in new buildings and construction projects will be reduced by 40% compared to a 2018 baseline. This builds on our city’s current policy which already requires all rezoning projects to conduct a Whole Building LCA and disclose the embodied carbon impacts.

At this moment when cities and countries around the world are declaring a Climate Emergency and developing plans to drive deep carbon reductions, other jurisdictions should follow Vancouver’s example and include a focus on embodied carbon. Most climate policies relating to the buildings sector focus on operational carbon, leaving embodied carbon as an untapped source of carbon reduction potential. While voluntary standards are useful, addressing embodied carbon at-scale requires a strong regulatory response.

One of the initiatives that I am most excited about is EDGE, a green building standard and certification system for over 140 countries. It’s like LEED, but designed to be much simpler so as to encourage broad adoption, including in developing countries. To get certified, EDGE requires buildings to reduce energy use, water use, and material impacts by 20 percent. While there is a modest cost for certification, EDGE offers a free web app that lets anyone build a simple model of their building, compare different design options, and explore cost-effective strategies to reduce environmental impacts.

(Source: EDGE)

For the materials section in EDGE, users can calculate the embodied energy of different material design options. Similar to embodied carbon, embodied energy looks at the fossil fuel energy use (rather than the carbon emissions) associated with a material’s lifecycle. My hope is that EDGE will consider shifting their focus to embodied carbon instead of embodied energy, as this would be more relevant from a climate change perspective. Embodied carbon is a relatively new concept, even to the North American buildings industry, so to introduce this critical measure to developing countries—where the most new construction is taking place—would be a game changer.

With these and other systems being implemented around the world, the entire green building industry is trending toward making embodied carbon a priority. Projects like the World Green Building Council’s Advancing Net Zero initiative are searching for ways to bring embodied carbon to the forefront of the discussion, while an organization like Architecture 2030 already includes action on embodied carbon as a central component in its overall plan.

Scale, Scale, Scale

While it’s encouraging to see the buildings industry start to focus on embodied carbon, at the current pace, it will likely take 10-20 years before it becomes standard practice for design teams to focus on reducing embodied carbon. Unfortunately, we just don’t have that much time. According to the Global Status Report 2017, here is the amount of new construction projected to take place over the next 40 years across different regions compared to the existing building stock.

(Source: Global Status Report 2017)

Architecture 2030 founder Ed Mazria pointed out in a recent talk that over the next 15 years, we will build the equivalent of 40 percent of the buildings that currently exist in the world. That means that if we wait until 2030 or 2035 to seriously address embodied carbon at-scale, we will have already built the equivalent of all the buildings we currently have in North America, South America, and Europe combined. As Mazria emphasizes, we can’t wait until 2030 to build net-zero carbon buildings. The new date is 2020. We need to act now. Every effort we make has to have an impact. Everything we do must scale up.

The buildings industry consumes almost half of the world’s material resources every year, so we cannot keep turning a blind eye to our embodied carbon footprint. To be clear, I am not saying that embodied carbon is more important than operational carbon. Both are critical. It’s just that, to date, our industry has focused heavily on operational carbon and has mostly ignored embodied carbon.

This needs to change, and it needs to change fast. Whether you are an architect, structural engineer, environmental consultant, developer, product manufacturer, or policy maker, the world needs you to champion the issue of embodied carbon. Advocate for incorporating embodied carbon on your projects, and make it standard practice within your firm. Now, more than ever, is the time for your leadership.

Let’s make 2019 the year of embodied carbon!

Anthony Pak is Principal at Priopta, one of the first firms in North America to provide a Parametric Life Cycle Assessment (LCA) consulting service for buildings. He is also the founder of Embodied Carbon Catalyst, a group that organizes bi-monthly events in Vancouver empowering industry professionals to champion the issue of embodied carbon on their projects and within their firms.