The effect of Embodied Carbon in Sustainable Cities
Cities and urban areas drive economic growth and boost the global GDP. However, the buildings in these settings adversely impact the environment, mainly due to their high levels of embodied carbon (EC). This comes at a time when the climate change crisis is looming and governments worldwide have set goals to reach net-zero carbon emissions.
What is EC? How does it impact cities, and is there any way to reduce its levels? Architecture, engineering and construction (AEC) professionals should be aware of EC and how it could impact the sustainable cities movement.
Here’s more about EC, its adverse effects on the environment and why it hinders sustainable city development.
What Is Embodied Carbon?
EC consists of the carbon emissions associated with a structure while it’s being built as opposed to when it operates. In other words, EC is the total carbon footprint of the activities performed and the construction materials used to develop the built environment.
All stages of the building’s life cycle, except the actual operation of the building, must be taken into account to estimate a building’s EC. According to the U.S. Department of Energy (DOE), EC includes any associated carbon emissions from these stages of a structure’s existence:
- Resource extraction
- Construction and installation
- Demolition and disposal of building materials
In contrast, emissions associated with a building’s p[eratopm are considered operational carbon (OC). Adding the EC and OC together can help determine a structure’s total carbon footprint.
For example, the carbon emissions that result from generating electricity in a building would be included in its operational carbon (OC) estimate. In 2021, the International Energy Agency (IEA) reported that global energy-related carbon emissions hit 36.3 gigatonnes, a record high. Much of this increase is due to the strong economic recovery in the industrialized world after the COVID-19 pandemic.
Surveyors, architects and building designers are typically responsible for determining a building’s embodied carbon throughout the design and construction processes.
The Negative Effects of Embodied Carbon and Its Impact on Sustainable City Development
It’s no secret that high levels of carbon emissions, including EC from construction, contribute to the greenhouse gas effect, ultimately causing significant environmental changes.
Countries worldwide are experiencing shifts in weather patterns, rising sea levels, melting ice and glaciers, extreme droughts and higher temperatures. These changes are concerning, but they also exacerbate other global issues. These include food and water insecurity, limited worker productivity, increased mortality rates and infrastructure damage.
Embodied carbon is not the only cause of global warming and climate change. However, it is a contributing factor that the AEC community and its professionals must work to resolve, especially if reaching net-zero emissions is the ultimate goal.
AEC Industry Focused on OC in Past Years
The AEC industry recently focused on improving building operational efficiencies. More structures offer smart technologies, like the Internet of Things (IoT), which is contributing to the smart cities movement and creating a cleaner, more sustainable built environment.
For instance, the industry made noticeable improvements in engineering for greater water and electrical efficiency. Modern structures can incorporate passive design choices, such as shading devices and building siting, to reduce their projects’ carbon footprints.
However, these basic improvements in a building’s operational efficiencies only do so much. Structures generate EC and OC, and reducing the OC in buildings is worthwhile but fails to address EC.
What improvements can be made in a building’s life cycle to reduce the amount of EC generated? It’s critical to consider EC and improve specific stages of buildings’ life cycles due to mounting pressure to decarbonize the AEC sector and build carbon-neutral structures.
Two Primary Reasons to Focus on EC Reduction, Without Ignoring OC
Increased EC and OC levels can harm the environment. However, there are two other reasons AEC professionals and industry leaders should consider reducing EC in buildings without ignoring OC.
1. Rapid Shifts in the Energy Sector
It’s no secret that the modern energy sector is undergoing rapid changes. New structures are shrinking their OC as the electrical grids that provide power become cleaner.
The energy sector is trying to electrify everything. Consider the federal government’s efforts to increase electric vehicle (EV) adoption, grant programs for states to build electric grid resilience and leverage smart grid technologies to further modernization.
The amount of OC in the built environment will decrease due to these efforts. Therefore, the AEC industry must focus on reducing the amount of EC in buildings.
2. Spikes in EC Emissions Undercut Net-Zero Efforts
The planet incurs spikes in EC every time a new structure is built. These high levels of EC cannot be reduced with increases in building OC or through other net-zero operations. OC levels rise while the building is in use, whereas EC levels are incurred at one time. Later upgrades in a structure’s systems do not have any effect on the levels of EC it has.
Reaching the critical goal of hitting net-zero emissions by 2030, as stated in the Paris Agreement, becomes much more difficult when the AEC sector only focuses on improving operational efficiencies.
One way the AEC industry can limit the negative impact of EC in buildings is by participating in the sustainable city movement. What are sustainable cities, and how would they help reduce EC?
How Sustainable Cities Combat EC
Every stage of the construction process, from resource extraction to demolition and materials disposal, contributes to a building’s total amount of EC. AEC professionals must look at current construction processes and implement effective strategies at each stage to reduce EC.
If vast improvements are made in each stage, buildings will be less carbon-intensive and the total amount of EC will decrease. It’s also critical for AEC companies to keep clients informed about how these changes may affect building performance to avoid potential legal issues.
Here is a list of potential changes in construction processes that could reduce EC in buildings and align with sustainable city development.
Use More Sustainable Building Materials
One change that can be effective in EC reduction efforts is increasing the use of sustainable building materials. Here are some of the natural materials that can be used during construction:
- Recycled metal
- Reclaimed wood
- Green thermal insulation
- Structured insulated panels
- Cement made out of recycled plastic
- Precast concrete slabs
Using these materials could reduce total EC in a building project.
Transition to Green Transportation
Materials must be transported from one place to another, but it’s well known that carbon emissions from the transportation sector are steadily increasing. Therefore, vendors and suppliers should focus on reducing energy consumption.
A great strategy to do this is to transition to green transit systems. It’s estimated that construction transportation emissions account for around 10% of all carbon emissions, illustrating how impactful changing to green transportation could be.
Adopt Sustainable Waste Management Practices and Minimize Waste
The total amount of waste associated with a building project can be minimized if you design the construction process with sustainable waste management. As a result, the total amount of EC would decrease.
Construction companies might be able to reuse or recycle building materials once they’ve reached the end of their life cycle. This would create a circular economy, which can positively impact other stages of the construction process.
Meet Green Building Certifications
A key component of creating a sustainable city is receiving various certificates from outside organizations. A few of the most common green building certifications include:
- Green Star
- Green Globes
Meeting these certification requirements will decrease EC in buildings and improve their marketability and property value. Earning certifications can improve ROI in several ways, like reducing operating costs and vacancies and increasing occupancy and rental income.
Considering EC Reduction Efforts in Modern City Planning
The AEC industry is critical in constructing and designing safe, functional buildings in large cities and small communities. The global population is steadily increasing — around 5 billion people are projected to live in cities by 2030, according to the United Nations.
As more people relocate to cities, AEC companies, state and local governments, and industry leaders must stress the importance of sustainable city development and how it can reduce EC in the built environment.