Embodied Carbon in the Built Environment―A Primer by Perkins&Will

Embodied Carbon in the Built Environment ― A Primer Summary of key resources, metrics, and actions to address embodied carbon in design and construction

April 22, 2020

Innovation starts with inquiry.

ACKNOWLEDGMENTS

Research

This report was authored by the research and sustainability team of the Vancouver and Calgary studios of Perkins and Will: Principal-in-charge: Kathy Wardle, Associate Principal and Director of Sustainability Lead Researcher: Manuela Londono, Sustainable Building Advisor Research Review Committee: Cheney Chen, Cillian Collins, Susan Gushe, Aaron Knorr, Mona Lemoine, Sindhu Mahadevan, Derek Newby. 1220 Homer Street Vancouver, British Columbia V6B 2Y5 1550–5th Street SW, Suite 401 Calgary, Alberta T2R 1K3 t +1 604 684 5446

In our never-ending quest for knowledge, we push limits, take risks, investigate, and discover. We constantly ask ourselves, “What if?” “What’s next?” This makes our ideas clearer, our designs smarter, our teams happier, and our clients more satisfied.

Contents

Introduction 4 1.

What’s at Stake?

2. Overview

4 5

Embodied Carbon Calculation Tools

Embodied Carbon Baselines and Benchmarks

Self-declared baseline

2. Methodology to create a baseline

3. Benchmark to create a performance target

Embodied Carbon Reduction Targets

Embodied Carbon Conservation Measures

Design and construction conservation measures

2. Non-design reduction strategies

13 13

Carbon Conservation Measures in the Design Process

Timelines for Action

Gaps in Industry Knowledge

Conclusion

Definitions

Acronyms

Endnotes

Works Cited

Introduction Global CO₂ Emissions by Sector: Image adapted from Architecture 2030

In response to climate emergencies declared around the world, the building industry must rapidly transition into a zero carbon sector that takes into account both operational and embodied carbon.

Lo Industry re m 30% ip su

Other 9%

Building Operations 28% Transportation 22%

Building Materials and Construction 11%

1. What’s at Stake? The building sector, which is responsible for 39% of global carbon emissions, presents a key opportunity to make an impactful reduction in global greenhouse gas (GHG) emissions. A breakdown of these emissions shows that 28% can be attributed to building operations with the remaining 11% attributed to the carbon embodied in building materials and generated by the construction process.1

DEFINITIONS greenhouse gas (GHG) Any gas that absorbs heat energy emitted from Earth’s surface,

The implementation of widespread energy efficiency codes and regulations

traps heat in the atmosphere,

has substantially reduced operational carbon emissions. A similar concerted

and radiates that heat back to

focus on quantifying and reducing embodied carbon would further the industry’s ability to reduce its carbon footprint.

Earth’s surface. These gases include carbon dioxide, methane, water vapour, ozone, nitrous oxide, and

In light of the climate crisis, the building industry has a collective responsibility to design buildings, communities, and cities with the lowest possible carbon emissions and with the aspirational goal of creating

chlorofluorocarbons (CFCs). embodied carbon emissions Carbon emissions associated

net zero operational and embodied carbon buildings. If we rise to this

with materials and construction

challenge, we will stay ahead of regulatory pressures and demonstrate the

processes throughout the whole life

kind of leadership building industry professionals are capable of.

cycle of a building.2 operational carbon emissions Carbon emissions associated with the energy used to operate a building.3 net zero carbon Achieved when CO2 emissions from human activities are balanced globally by CO2 removals over a specified period.4

2. Overview As the building industry continues to design better performing buildings, the significance of addressing embodied carbon emissions is magnified. With an increased awareness of embodied carbon, a new body of literature and best practices has emerged within the industry. This primer distills current and emerging industry knowledge, and focuses on the practical measures that our industry can immediately implement to limit embodied carbon in the built environment. Our knowledge is derived from a literature review of publications and standards published by the following organizations: ǌ Athena Sustainable Materials Institute (Athena Institute) ǌ Bionova ǌ Canada Green Building Council (CaGBC) ǌ Carbon Leadership Forum ǌ City of Vancouver ǌ FutureBuilt ǌ Government of France ǌ Intergovernmental Panel on Climate Change (IPCC)

ǌ International Living Future Institute (ILFI) ǌ London Energy Transformation Initiative (LETI) ǌ Microsoft ǌ Natural Resources Canada (NRCAN) ǌ Royal Institute of British Architects (RIBA) ǌ Thornton Tomasetti ǌ World Green Building Council (WGBC)

Within this report, we offer a summary of embodied carbon, whole building life cycle assessment, tools, metrics, timelines for action, and opportunities for implementing embodied carbon conservation measures during a typical building design process. Our companion Embodied Carbon in the Built Environment ― Executive Summary provides a high-level synopsis of this document. 

Operational Carbon



Embodied Carbon

The significance of tackling embodied carbon emissions has become magnified as a result of higher energy efficiency (lower operational carbon) in buildings.

Embodied Carbon Calculation Tools WHO

LE LIFE CARBON

PR OD

LIF ND E

E STAG

ES S

PR OC

A4 Transport

A3 Manufacturing

RU C

A ST

IFE

OPERATIONAL CARBON

EN C3 Waste Processing

RONT CARBON

BEYO

UPF

END O

C4 Disposal

A2 Transport

E AG ST

D Benefits and Loads beyond the Life Cycle

A1 Raw Material Supply

EMBO C ARB DIED ON

B6 Operational Energy Use

USE C ARBON

C2 Transport

N CO

USE STAGE B1 Use B2 Maintenance C1 De-construction Demolition

B3 Repair B4 Refurbishment B5 Replacement

Image adapted from BS EN 15978:2011 Sustainability of Construction Works— Assessment of Environmental Performance of Buildings—Calculation Method

A5 ConstructionInstallation Process

A building’s whole life carbon is made up of the following life

Building Information Modelling (BIM) tools, excel, and

cycle stages: product stage, construction process stage, use

energy modeling software.

stage, and end of life stage, as defined by and derived from

Another notable tool is the Embodied Carbon in

European Standard EN 15978.

Construction Calculator (EC3), this tool is developed by

The stages indicated by the blue line (A1-C4) make up the

C-Change Labs and Skanska. While not a WBLCA tool,

total embodied carbon—and in the case of buildings, it can

it is intended to empower the building industry to make

be calculated by completing a Whole Building Life Cycle

“carbon smart choices” by providing public access to carbon

Assessments (WBLCA). Life cycle stage B6—Operational

emissions data for individual building materials. The tool

Energy Use (indicated in yellow) makes up the building’s

allows users to view, benchmark, and compare the carbon

operational carbon.

impact of building materials, and can be used during the development of specifications and material procurement.

The most common tools to complete a WBLCA of projects located in North America are the Athena Impact Estimator

There are many tools available to meet different user

for Buildings, Tally, and OneClick LCA.

needs, in choosing the right tool, it is important to consider factors such as:

The Athena Impact Estimator for Buildings is a software

ǌ project location,

application developed by the Athena Sustainable Materials Institute, a non-profit research collaborative. The Athena

ǌ stage of the project,

Institute maintains a robust LCA database for construction materials and systems in Canada and the U.S. and this

ǌ available project data, and

database powers the Impact Estimator tool. To create

ǌ the format of the project’s bill of materials.

a model, users can either input building assemblies by following dialogue boxes or import a bill of materials. Tally is a Revit plug-in developed by KT Innovations, an affiliate of KieranTimberlake. As a Revit plug-in, the tool allows designers to evaluate the environmental impact of design options in parallel with the development of the project. Tally’s LCA database is representative of U.S. data and it combines material attributes, assembly details, and architectural specifications with Thinkstep’s GaBI Life Cycle

DEFINITIONS

Inventory (LCI) database.

Environmental Product

OneClick LCA is developed by Bionova, a software developer

Declaration (EPD)

focused on environmental impact calculations. OneClick

A document that quantifies

LCA’s database relies on Environmental Product Declarations

environmental information on the life cycle of a product to enable

(EPDs), information from manufacturers, and some generic

comparisons between products

building material databases. Users can import data from

fulfilling the same function.

Carbon Designer (Bionova’s early stage carbon estimator), 7

Embodied Carbon Baselines and Benchmarks

In order to understand how to measure embodied carbon, it is important to differentiate between a baseline and a benchmark: Baseline: A baseline design is produced by the WBLCA modeller and is based on what is typical for the building type, a previous project that is similar, or an earlier iteration of the proposed project.5 Benchmark: A benchmark is based on a statistical analysis of the current building stock and represents an “average performance” of a building archetype.6 Establishing a baseline or benchmark at the outset is important to evaluate a project’s performance. They allow for comparisons between similar projects or to the average performance of existing projects. When it comes to establishing baselines and benchmarks for embodied carbon, the three most common approaches are: 1. Self-declared baseline 2. Methodology to create a baseline 3. Benchmark to create a performance target

DEFINITIONS carbon dioxide equivalent (CO2e)

Benchmark Reduction from Baseline

A standard unit for measuring

Reduction from Benchmark

carbon footprints, it expresses the impact of a greenhouse gas in terms of the amount of CO2 it would

kgCO2e

take to create the same amount of

BASELINE

PROPOSED

MODEL

warming. life cycle assessment (LCA) A scientific method for calculating the environmental footprint of materials, products, and services over their entire lifetime.

1. Self-declared baseline

3. Benchmark to create a performance target

In a self-declared baseline, users report the life cycle

Benchmarks are the least flexible category, representing the

assessment (LCA) results of a status quo building with the

average performance of a sample of buildings. Benchmarks

same scope, size, function, and energy performance as the

can be used to evaluate building performance against

proposed project. This baseline building would represent

the maximum greenhouse gas emissions permitted for the

typical construction practices and minimum building code

project, which can be adjusted by factors like building type

requirements. Schemes that use this type of baseline to rate

and size. An example of this method is the Government

embodied carbon reductions provide general guidance on

of France’s Bâtiment à Énergie Positive et Réduction

creating a baseline building. However, due to the flexibility

Carbone certification which uses a tiered system to assess

of this method, comparing performance among projects

the building’s performance. In this program, projects are

is not reliable and this methodology is better suited to

required to demonstrate that the building’s embodied

compare different design options for the same project.

carbon does not exceed an absolute target derived from

the average performance of the local building stock. The

Rating systems that use this approach include: CaGBC LEED

regulation offers adjustments to the absolute target based

v4 and v4.1, CaGBC Zero Carbon Building Design Standard

on a formula that allows inputs for project variables such

v2, Green Globes, ILFI Zero Carbon Standard, and ILFI Living

as location, altitude, floor area, intended use, and number

Building Challenge.

of parking spaces. These variables, and corresponding coefficients are carefully defined within the regulation.11

2. Methodology to create a baseline

The industry recognizes that in order to assess real progress

Regulations and schemes that propose a rigorous

in reducing GHGs we need absolute targets based on

methodology to create a baseline use well-defined

statistically significant benchmarks—this is undoubtedly a

calculation methods.8 This approach reduces flexibility for

great endeavour. Research leaders like the Athena Institute

users, but allows some adjustment to account for specific

have proposed thorough methodologies for creating

project attributes resulting in a more confident outcome

benchmarks based on current Canadian practices, and

when comparing reductions among different projects

which will eventually replace self-defined benchmarks.12

with similar characteristics.9 For example, programs like

The Athena Institute, Bionova, the City of Vancouver, and

Norway’s FutureBuilt detail the steps to create a baseline

the Canada National Research Council are leading efforts

building. Project teams must use One Click LCA Norway and

to collect project specific data and develop benchmark

only limited adjustments can be made to the Norwegian

databases for municipal, Canadian, and/or North American

reference buildings available in the software. The reference

buildings. A number of organizations such as LETI, WGBC,

buildings in OneClick LCA Norway are derived from a

ILFI, and Microsoft call for data sharing and transparency

modelling process that took data from existing designs

from the building industry to accelerate the development of

representing current building practices in the region, the

knowledge, benchmark data, and tools.

minimum requirements of building regulations and codes, and building location.10

Embodied Carbon Reduction Targets

Embodied carbon reduction targets proposed by different rating schemes and regulations vary significantly as can be seen in the summary below. Some programs require the purchase of carbon offsets as a mechanism to help achieve net zero embodied carbon:

Bâtiment à Énergie Positive et Réduction Carbone Location:

France

Baseline/Benchmark:

Benchmark to create a performance target

Reduction Targets:

Building Type

Not to exceed the following thresholds (maximum kgCO2e/m2)

Single family

700

650

Multi-Unit Residential Building (MURB)

800

750

Office

1,050

900

Other regulated building types

1,050

750

WBLCA Required:

Best Practice―2025

Best Practice―2030

Yes

CaGBC Zero Carbon Building Design Standard v2 Location:

Canada

Baseline/Benchmark:

Self-declared baseline

Reduction Targets:

% Reduction not specified. Embodied carbon must be reported and high-quality carbon offsets must be purchased.

WBLCA Required:

Yes

City of Vancouver Green Policy for Rezonings Location:

Vancouver, Canada

Baseline/Benchmark:

Currently no baseline is reported. The Policy will be updated in 2021 and a baseline method will be determined.

Reduction Targets:

Currently there is not reduction requirements. The Policy will be updated in 2021 and a reduction target will be established.

WBLCA Required:

Yes

FutureBuilt Location:

Norway

Baseline/Benchmark:

Methodology to create a baseline, scope includes GHG emissions from occupants’ transportation to the building.

Reduction Targets:

50% reduction in GHG emissions.

WBLCA Required:

Yes 10

International Living Future Institute Location:

Global

Baseline/Benchmark:

Self-declared baseline

Reduction Targets:

Zero Carbon Certification

10% reduction from the baseline ― <500 kgCO2e/m2 Purchase carbon offsets for the remaining embodied carbon amount for any new material used.

Living Building Challenge Energy Petal

20% reduction from the baseline. Purchase carbon offsets for the remaining embodied carbon amount for any new material used.

WBLCA Required:

Yes

LEED v4.1 Location:

Global

Baseline/Benchmark:

Self-declared baseline

Reduction Targets:

0–20% reduction from the baseline

WBLCA Required:

Yes—for Option 4 of Materials and Resources Credit Building Life Cycle Impact Reduction

London Energy Transformation Initiative (LETI): Climate Emergency Design Guide Location:

London, England

Baseline/Benchmark:

Fixed Scale ― Residential: 800 kgCO2e/m2 | Commercial: 1,000 kgCO2e/m2

Reduction Targets:

Building Type

Not to exceed the following thresholds

WBLCA Required:

Best Practice―2020 max. kgCO2e/m2

min. materials from reused sources

Best Practice―2030 min. materials that can be reused at end of life

max. kgCO2e/m2

min. materials from reused sources

min. materials that can be reused at end of life

Residential

500

30%

50%

300

50%

80%

Commercial

500

30%

50%

350

50%

80%

Yes

RIBA Sustainable Outcomes Guide 2019 Location:

Global

Baseline/Benchmark:

Fixed Scale ― Residential: 1,000 kgCO2e/m2 | Commercial: 1,100 kgCO2e/m2

Reduction Targets:

Building Type

Not to exceed the following thresholds (maximum kgCO2e/m2)

Residential

600

450

300

Commercial

800

650

500

WBLCA Required:

Yes

Best Practice―2020

Best Practice―2025

Best Practice―2030

Embodied Carbon Conservation Measures Understanding the main sources of both embodied and operational carbon can equip project teams to focus efforts on the largest emitters and select targeted actions that have the most significant overall effect.

Structural Columns

6% Structural Framing

←

10%

More than 80% of the embodied carbon in a building’s structure is in the floor slabs, walls, and structural foundations.

Structural Foundation

Reference: Adapted from the project-based study of the embodied carbon of more than 600 buildings by Thornton Tomasetti.

20% Walls

↓

21%

The GHG emissions by energy end use for commercial and institutional buildings in 2017. Space heating, lighting, and auxiliary equipment make up 85% of the total GHG emissions for operations. The GHG emissions of each end use is a function of energy use and fuel source.

Floors

43%

Reference: Natural Resources Canada (NRCAN)—Canada’s GHG Emissions by Sector, End Use and Subsector—Including ElectricityRelated Emissions.

A holistic approach to achieve total carbon reductions in the built environment should Street Lighting 1% Space Cooling 4%

include operational carbon, embodied carbon, and carbon associated with the transportation of building users. In this section we focus on design strategies to limit embodied carbon, but recognize the emissions associated with

Auxiliary Motors 3%

building operations and transportation of

Lighting 10%

users require equal attention.

Auxiliary Equipment 12%

Water Heating 7% Space Heating 63%

ǌ Evaluate refrigerants in building equipment as they can be

With more than 80% of the embodied carbon residing in a building’s structure, carbon can be mitigated through careful

a significant source of GHG emissions.

design and specification.

ǌ Optimize the procurement process by requesting and

Embodied carbon conservation measures (ECCMs) that

reviewing product transparency documents in order to

owners, designers, and builders can act on fall into two

follow through with design choices.

general categories:

2. Non-design reduction strategies 1. Design and construction conservation measures

Non-design reduction strategies are measures that cannot

Design and construction conservation measures are

be quantified using WBLCA or other quantitative tools,

achieved from design decisions that can be quantified using

yet can accelerate the adoption of low carbon products,

LCA, including:

technologies, and design strategies.

ǌ Reuse buildings and building materials.

The World Green Building Council emphasizes the importance of enabling change in the building sector

ǌ Consider foundation requirements of potential sites to

through collaboration, communication, education,

optimize the building structure.

innovation, and regulation. The adoption of these actions

ǌ Conduct studies to minimize column sizing, maximize

by supply-side players, demand-side players, policy makers,

column spacing, optimize the building shape, and reduce

and non-governmental organizations will accelerate

the depth of slabs resulting in the use of less material.

the shift to low or zero carbon solutions and will create

ǌ Refine the program to eliminate redundant spaces.

“positive feedback loops that stimulate market demand

ǌ Design for flexibility, adaptability, future disassembly,

also invigorate the development, demonstration, and

and uptake of net zero embodied carbon.” This shift will

deconstruction, and reuse.

commercialization of affordable technologies that will help achieve net zero embodied carbon without relying heavily

ǌ Design for efficient use of materials and where possible minimize layering of materials—especially when it comes

on carbon offsets.13

to interior finishes.

In British Columbia, the introduction of the BC Step Code and the City of Vancouver’s Zero Emissions Building Plan are

ǌ Choose low carbon materials.

two examples of policy leading effective change in the local

ǌ Limit the carbon impact of structural materials such as

building industry.

concrete, steel, and wood by carefully specifying and selecting the materials:

DEFINITIONS

‒ Concrete: Request Environmental Product Declarations (EPDs) for design mixes and establish

embodied carbon conservation

a concrete carbon budget for the project in

measures (ECCMs)

collaboration with concrete suppliers.

Strategies and technologies implemented to reduce the

‒ Steel: Request high recycled content, source steel

embodied carbon in building

from mills that use Electric Arc Furnaces (EAFs),

assemblies and materials.

understand the local energy grid of the mill, and the

energy conservation measures

distance the product will be transported.

(ECMs)

‒ Wood: Source wood from sustainably managed

Strategies and technologies

forests so there is confidence that the forest will be

implemented to reduce the energy

maintained to maximize carbon sequestration.

consumption of a building.

Carbon Conservation Measures in the Design Process

ǌ Establish massing to study the embodied carbon impacts of potential building forms through WBLCA

EMBODIED CARBON

ǌ Host design workshop to explore embodied carbon conservation measures (ECCMs)

ǌ Refine program to eliminate redundancies

ǌ Initiate energy analysis—box modelling or conceptual design modelling ǌ Discuss fuel sources

ǌ Update WBLCA model

ǌ Conduct thermal bridge calculations ǌ Complete energy model to assess load reductions and systems selection ǌ Draft outline specification to identify components critical to energy performance ǌ Establish Basis of Design for assemblies, glazing ratios, occupancy usage, ventilation strategy, shading strategies

OPERATIONAL CARBON

Design Development

ǌ Establish Basis of Design for structural system, envelope, foundations, landscape, hardscape, and other assemblies with high embodied carbon impact

Schematic Design

Establish a carbon budget in kg CO2e

ǌ Discuss structural options, their associated carbon footprint, and the cost and schedule implications

ǌ Complete environmental analysis—climate and site

ǌ Collaborate with the builder to develop embodied carbon requirements in the specifications and ensure follow through in the procurement process

ǌ Draft outline specification to identify materials and systems critical to reducing embodied carbon

ǌ Reduce material use by exploring various massing and foundation options

Concept Establish a carbon budget in kg CO2e

ǌ Collaborate with landscape and civil designers to analyze carbon impact of landscape and hardscape

ǌ Complete an early stage WBLCA

ǌ Host design workshop to explore energy conservation measures (ECMs)

ǌ Optimize structure, including column sizing, column spacing, slab depth, and roof assembly

ǌ Study structural and envelope systems

ǌ Study the possibility of retaining existing building components and materials

ǌ Establish goals to design for flexibility, adaptability, future disassembly, deconstruction, and reuse

ǌ Identify assemblies and materials with the largest embodied carbon impact and study reduction strategies through WBLCA

ǌ When assessing EPDs of comparable products take into account the LCA scope, declared units, and whether it is industry wide or product specific

ǌ Optimize design, establish occupancy rates, reconcile ASHRAE/code requirements, and study ECMs ǌ Update energy model ǌ Collaborate with mechanical designer and HVAC supplier to select equipment that uses refrigerants with low global warming potential and avoid refrigerant leakages

As a design firm, we strive to achieve carbon reductions in all projects. Achieving low carbon designs requires the engagement of the entire project team. This iterative process, which ideally starts in early design, is continually refined throughout design and construction. By integrating low carbon design thinking and practices from the beginning, we are able to make informed decisions based on the project’s goals. This design timeline illustrates key considerations to reduce the operational and embodied carbon of our projects.

ǌ Incorporate EPD requirements and CO2e limits for key materials in the specifications

ǌ Confirm the impact of material choices and efficiencies established in design through WBLCA

ǌ Prepare drawings and specifications incorporating all elements critical to energy performance, including airtightness detailing, and thermal bridge detailing ǌ Review value engineering proposals and potential implications on energy performance goals

ǌ Review submittals and product substitutions to confirm low carbon materials are maintained throughout procurement and construction ǌ Update WBLCA as required

ǌ Monitor on-site practices to ensure compliance with energy performance requirements ǌ Update energy model as required ǌ Conduct airtightness testing ǌ Commission building systems to ensure design intent is met

Post Occupancy

ǌ Review structural drawings and specifications to confirm the embodied carbon impact as the structural design is refined

Construction Administration

Tender and Construction Documents

ǌ Include requirements for substitutions and alternate products in the specifications

ǌ Reflect on lessons learned and apply them on future projects

ǌ Complete measurement and verification to refine operations and meet energy reduction goals ǌ Reflect on lessons learned and apply them on future projects

Timelines for Action

The Intergovernmental Panel on Climate Change (IPCC) warns the world that in order to limit global warming to 1.5°C, we will require “rapid and far-reaching” action to reach a 45% reduction in CO2 emissions by 2030 and net zero emissions by 2050.17 Building upon this call for action, many organizations, such as the World Green Building Council, the American Institute of Architects, Microsoft, and the City of Vancouver have set accelerated timelines for carbon emissions reductions. Currently, embodied carbon reduction targets are voluntary, but France, Norway, the City of Vancouver, Washington State, and California have indicated that mandatory embodied carbon reduction targets for whole buildings and specific materials will be implemented in the near future. The timeline graphic below outlines embodied carbon reduction targets set by leading organizations.

Getting to Zero

2020

2025

2030

2040

Embodied Carbon Reduction Targets

World GBC

40%

AIA 2030 Challenge

50%

City of Vancouver Climate Emergency Response

40%

Microsoft’s commitment to be “carbon negative” by 2030 means that they will remove more carbon than they emit each year.

Microsoft

LETI Climate Emergency Design Guide RIBA Sustainable Outcomes Guide 2019

40%

48–55%

65%

62–70%

2050

Gaps in Industry Knowledge

Conclusion

While great strides are being made to conserve operational

The world shares a finite carbon budget and a tight

energy through policy, innovation and advancements

deadline before we see irreversible changes in our climate.

in technology, industry leaders recognize more action is

For this reason, gaps in data and technology cannot halt

required to decarbonize the building sector.

progress in further decoupling the development of the built environment from carbon emissions.

When it comes to embodied carbon, the building industry is in the early days of establishing best practices, and

We expect to see policies emerge from local jurisdictions

more research and application is required. In the near

and planning authorities that will target embodied carbon

future, we expect to see the development of policy and

reductions in the built environment. We each have a

regulation, consistent baselines, robust benchmarking data,

responsibility and role to play in sending market signals to

transparency of building and material performance, and

clients, consultants, contractors, and manufacturers to invest

scalable technology that is required to achieve meaningful

in innovative products. Above all, achieving a zero carbon

embodied carbon reductions.

future for the industry will require major collaboration. Now more than ever, we are being urged to make bold commitments, learn by doing, and share lessons along the way. By focusing on the most impactful design decisions, we believe we can decarbonize the built environment.

Definitions

Acronyms

Anthropogenic emissions: The IPCC defines anthropogenic emissions as “emissions of greenhouse gases (GHGs), precursors of GHGs and aerosols caused by human activities”.

CO2e: Carbon Dioxide Equivalent ECM: Energy Conservation Measures ECCM: Embodied Carbon Conservation Measures

Baseline: A baseline design is produced by the WBLCA modeller and is based on what is typical for the building type, a previous project that is similar, or an earlier iteration of the proposed project.

EPD: Environmental Product Declaration GHG: Greenhouse Gas

Benchmark: A benchmark is based on a statistical analysis of the current building stock and represents an “average performance” of a building archetype.

LCA: Life Cycle Assessment LCI: Life Cycle Inventory

Carbon dioxide equivalent (CO2e): A standard unit for measuring carbon footprints, it expresses the impact of a greenhouse gas in terms of the amount of CO2 it would take to create the same amount of warming.

WBLCA: Whole Building Life Cycle Assessment

Embodied carbon conservation measures (ECCMs): Strategies and technologies implemented to reduce the embodied carbon in building assemblies and materials. Embodied carbon emissions: Carbon emissions associated with materials and construction processes throughout the whole life cycle of a building. Energy conservation measures (ECMs): Strategies and technologies implemented to reduce the energy consumption of a building. Environmental Product Declaration (EPD): A document that quantifies environmental information on the life cycle of a product to enable comparisons between products fulfilling the same function. Greenhouse gas (GHG): Any gas that absorbs heat energy emitted from Earth’s surface, traps heat in the atmosphere, and radiates that heat back to Earth’s surface. These gases include carbon dioxide, methane, water vapour, ozone, nitrous oxide, and chlorofluorocarbons (CFCs). Life cycle assessment (LCA): A scientific method for calculating the environmental footprint of materials, products and services over their entire lifetime. Low-carbon energy sources: Energy sources that emit low amounts of GHGs, including hydropower, solar power, wind power, and nuclear power. Net negative emissions: According to the IPCC, “a situation of net negative emissions is achieved when, as result of human activities, more greenhouse gases are removed from the atmosphere than are emitted into it.” Net zero carbon: Achieved when CO2 emissions from human activities are balanced globally by CO2 removals over a specified period. Operational carbon emissions: Carbon emissions associated with the energy used to operate a building.

Endnotes

1. See Canada Green Building Council. 2. See Canada Green Building Council. 3. See Canada Green Building Council. 4. See Masson-Delmotte, Zhai and Pörtner. 5. See Bowick and O’Connor, Reducing Embodied Environmental Impacts of Buildings. Policy Options and Technical Infrastructure. 6. See Bowick and O’Connor, Reducing Embodied Environmental Impacts of Buildings. Policy Options and Technical Infrastructure. 7. See Bionova Ltd, and (Bowick, O’Connor and Meil, Wholebuilding LCA Benchmarks. A methodology white paper. 8. See Bionova Ltd. 9. See Bionova Ltd. 10. See Selvig. 11. See Ministère de L’Environnement, de L’Energie et de la Mer. 12. See Bowick, O’Connor and Meil, Whole-building LCA Benchmarks. A methodology white paper. 13. See World Green Building Council. 14. See Canada Green Building Council. 15. See Canada Green Building Council. 16. See Masson-Delmotte, Zhai and Pörtner. 17. See Masson-Delmotte, Zhai and Pörtner.

Works Cited

Benke, Brad, Dave Walsh and Meghan Lewis. “Road Map to Reducing Building Life Cycle Impacts. A Timeline of Key Milestones + Actions.” 23 May 2019. Bionova Ltd. “The Embodied Carbon Review.” 2018. Bowick, Matt and Jennifer O’Connor. “Carbon Footprint Benchmarking of BC Multi-Unit Residential Buildings.” 2017. —. “Reducing Embodied Environmental Impacts of Buildings. Policy Options and Technical Infrastructure.” 2019. Bowick, Matt, Jennifer O’Connor and Jamie Meil. “Whole-building LCA Benchmarks. A methodology white paper .” 2017. Canada Green Building Council. Zero Carbon Building – Design Standard Version 2. Canada Green Building Council, 2020. City of Vancouver, Green Building Policy for Rezonings (2 May 2018). FutureBuilt. “FutureBuilt 10 Years.” Annual Report. 2019. International Living Future Institute. “Embodied Carbon Guidance. A Resource for Calculating and Reducing Embodied Carbon.” 18 December 2019. London Energy Transformation Initiative. “LETI Climate Emergency Design Guide. How new buildings can meet UK climate change targets.” 2020. Masson-Delmotte, Valerie, et al. “Global warming of 1.5°C. An IPCC Special Report on the impacts of global warming of 1.5°C above pre-industrial levels and related global greenhouse gas emission pathways, in the context of strengthening the global response to the threat of climate change, sustainable development, and efforts to eradicate poverty.” 2018. In Press. Ministère de L’Environnement, de L’Energie et de la Mer. “Référentiel Energie-Carbone pour les Bâtiments Neufs.” October 2016. Natural Resources Canada. “Canada’s GHG Emissions by Sector, End Use and Subsector – Including Electricity-Related Emissions.” n.d. Natural Resources Canada. Royal Institute of British Architects. “RIBA Sustainable Outcomes Guide.” Guide. 2019.

Selvig, Eivind. “FutureBuilt. Selection of Reference Building Materials.” 2019. 20 February 2020. Smith, Brad. “Microsoft Will be Carbon Negative by 2030.” 16 January 2020. Official Microsoft Blog. Thornton Tomasetti. “News: Thornton Tomasetti Shares Results of Comprehensive Embodied Carbon Measurement Study.” 14 November 2019. 20 February 2020. Urban Land Institute Greenprint Centre. “Embodied Carbon in Building Materials for Real Estate.” 2019. World Green Building Council. Bringing Embodied Carbon Upfront. Coordinated action for the building and construction sector to tackle embodied carbon. September 2019.

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