IF YOU DESIGN GREEN BUILDINGS
BUT IGNORE EMBODIED CARBON
YOU ARE MISSING HALF OF THE EQUATION
Embodied Carbon refers to the carbon emissions associated with construction materials such as concrete, steel, wood, glass, and insulation.
What is Life Cycle Assessment (LCA)?
LCA is the scientific method for quantifying embodied carbon as well as other environmental impacts. Through LCA, we can analyze the environmental impacts of materials through all life-cycle stages, including resource extraction, manufacturing, transportation, construction, operation, and end of life.
Embodied Carbon from
new construction accounts for at least 11% of global CO2 emissions each year
Operational Carbon from
energy used to operate
all existing buildings emits
28% of global CO2 emissions
Global new construction
and major renovation
is projected to DOUBLE
the building floor area
that currently exists
on the planet by 2060 (230 billion m2)
This is equivalent to
building an entire
NEW YORK CITY
for the next 40 years
Embodied Carbon will be responsible for
ALMOST HALF of total new construction
between now and 2050
Embodied Carbon vs Operational Carbon
Embodied carbon results can vary widely, with results ranging from 100 to over 1000 kgCO2e/m2, as you can see in the data visualization below, which is a compilation of over 1000 Whole Building LCA studies from around the world.
Operational carbon emissions can also vary widely, depending on the energy efficiency of the building, the carbon intensity of the electricity grid, and the climate.
For example, the City of Vancouver's rezoning policy requires buildings to meet operational carbon intensity limits between 3 to 8 kgCO2e/m2/year. These are very low numbers, reflective of near Passive House level energy efficiency and a low carbon electricity grid powered mostly by hydro. Baseline buildings in Vancouver could have operational carbon around 20 kgCO2e/m2/year, while cities like Calgary may have baseline performance around 71 kgCO2e/m2/year.
Embodied carbon is not more important than operational carbon, but we also cannot afford to ignore it. We must make smart design decisions to reduce both embodied and operational carbon.
Embodied Carbon results from over 1000 buildings
The Carbon Leadership Forum compiled over 1000 Whole Building LCAs from around the world as part of their Embodied Carbon Benchmark Study. Explore the visualization below to see how embodied carbon varies by region, building type, floor area, and the number of storeys.
What are the drivers for addressing embodied carbon
and using LCA on projects?
1. Voluntary Standards
Through the MRc1: Building Life-Cycle Impact Reduction credit, projects can receive 1 LEED point just for performing an LCA study and up to 5 points for a 20% reduction in embodied carbon relative to a baseline building. This credit is often overlooked and can play a big role in projects achieving their targeted level of certification.
Requires calculating embodied carbon emissions through an LCA study starting at the Schematic Design phase. Also required to apply two "Impact and Innovation" strategies. 2 of the 5 pre-approved strategies are:
An embodied carbon reduction of at least 20% compared to baseline building.
Upfront carbon emissions equal to or less than zero.
In ZCB Performance v2, embodied emissions are required to be offset.
Projects must demonstrate a 10% reduction in embodied carbon and not exceed 500 kgCO2e/m2, with remaining embodied emissions offset through approved carbon offset provider.
Projects must demonstrate a 20% reduction in embodied carbon, with remaining embodied emissions offset through approved carbon offset provider.
2. Policies and Regulation
City of Vancouver - Rezoning
Since 2017, the City's Green Building Policy for Rezoning (Requirement B.6.2) has required calculation and disclosure of LCA results in early design for rezoning submissions, which needs to be updated for Building Permit and Occupancy Permit. This rezoning policy will be updated in 2021 and will likely require a certain percentage reduction in embodied carbon. As part of the City's Climate Emergency Response, it has committed to a 40% reduction in embodied carbon for all new buildings and infrastructure by 2030, relative to a 2018 baseline.
World Green Building Council
The WorldGBC has recently released a call to action report Bringing Embodied Carbon Upfront, which also calls on the global construction industry to target a 40% reduction in embodied carbon from new buildings and infrastructure by 2030.
Policies and Standards Globally
There are over 100 standards and policies around the world that address embodied carbon, which are detailed in the Embodied Carbon Review by Bionova.
3. Market Leadership
Leading architects, engineers, developers, and manufacturers understand the importance of addressing embodied carbon and are already demonstrating leadership in this domain, even if it is not currently required by policies or standards.
While embodied carbon poses a big challenge to the industry, it also presents a major opportunity to those that demonstrate leadership in this domain.
Think of all of the companies, products, technologies, design strategies, and policies focused on reducing operational carbon. Compare that with the relatively little that has been done to address embodied carbon.
This is why we think those firms who act now to develop their expertise and competence in reducing embodied carbon will have a competitive advantage. It is also what is required of our industry, which has a major role to play in tackling the climate crisis.