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02 – Who’s Responsible for Carbon Emissions, Anyway?

How do we determine who is responsible for carbon emissions within the built environment? This article identifies how emissions are attributed to organizations, considers the scope of design teams’ emissions, and begins investigating the magnitude of our emissions.

Attributing Emissions

The Greenhouse Gas Protocol Corporate Standard framework is the most common way of sorting out responsibility for emissions, categorizing them into Scopes 1, 2, and 3. This standard is recognized by over 92% of Fortune 500 companies, educational institutions, many Countries and Cities, and may soon be required by the US Security and Exchange Commission to be part of all company’s disclosures. Many companies already report these scopes of emissions though transparency organizations like CDP.

  • Scope 1: Direct Emissions controlled by an entity, primarily emissions from owned vehicles and on-site combustion such as fossil fuel fired boilers in buildings.
  • Scope 2: Indirect emissions from purchased energy, primarily electricity.
  • Scope 3: Optional. Includes purchased goods and services (upstream) as well as the use of sold products (downstream). This includes any emissions from third parties that are integral to the business. The boundary for Scope 3 is not clearly defined, and some companies report only a partial Scope 3.
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The Greenhouse Gas Protocol Corporate Standard organizes emissions reporting into Scope 1, 2, and 3. Many of the building-related emissions are illustrated in this diagram.

Scope 1 emissions are, by definition, directly controlled by a company. They are also unique to that company, so no other entity would count them as Scope 1. This means that if every company eliminated their Scope 1 emissions we would live in a carbon balanced society. To provide incentives for this, market-based solutions like carbon fees are often levied on emissions from each entity’s Scope 1, called a ‘polluter pays’ system.

The GHG Protocol does double-count emissions up and down the value chain. For example, electricity emissions are counted as Scope 1 by the utility that produces it, Scope 2 by the electricity consumer, and part of Scope 3 for an entity that purchases goods produced with the electricity. In this example, the double counting allows any company that is part of the value chain to incentivize or demand more upstream renewable energy, lowering total emissions across the chain.

Many leading companies reduce their carbon footprint from electricity purchases (Scope 2) further by purchasing 100% renewable energy through green tariffs or a Power Purchase Agreement: Microsoft, Apple, Google, Amazon, and Johnson and Johnson are just a few. Some companies are also taking responsibility for their Scope 3 supply chains and outsourced activities, using their leverage as buyers to reduce their total Scope 3 emissions.

The GHG Protocol is useful for comparing a company’s progress toward zero, but comparing total carbon emissions between companies is not as useful as it would appear to be. This is because Scope 3 emissions are optional, less well defined, and tend to be much larger than Scope 1 and 2 emissions because they include many upstream and downstream impacts of a business. Another complication is that outsourcing activities shift what may have been Scope 1 and 2 activities into Scope 3; for example, a company that owns vehicles that deliver goods would include tailpipe emissions in Scope 1, whereas the deliveries by a third party would be in Scope 3.

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Each role within the buildings industry has different Scope 1, 2, and 3 emissions. Most entities have direct control of reductions for their Scope 1 and 2 emissions, but design and construction teams have substantial control of their Scope 3 emissions as well. Note that since Scope 3 boundaries are not clearly defined, an entity could consider nearly any emissions source within their Scope 3. This diagram is based on one by Jane Anderson, Construction LCA

Designers: It’s all about the Buildings

With the design and construction industry responsible for design, coordination, specifications, procurement, installation, and sometimes maintenance of buildings, we also bear much of the responsibility for building emissions. Despite budgets and other constraints not allowing complete latitude, we have significant pull as trusted advisors to our clients in shaping their goals, in creating demand for environmentally preferable products, and by tracking and reducing building emissions.

To put building emissions in context of a design firm’s operational emissions: the emissions from LMN’s projects designed in 2020 (including embodied carbon and the first 30 years of operational energy use emissions) are more than 600x our annual office carbon footprint (described below), even though half of LMN’s buildings (by count and total area) from our 2020 reporting year are on track to be certified as ‘Zero Carbon’ through ILFI’s Zero Carbon or USGBC’s LEED Zero Carbon program.

This confirms that reducing our client’s emissions – generally our Scope 3 – is by far our biggest lever: eliminating non-renewable energy like fossil fuels and other emitting sources used on site (Scope 1), reducing the demand for electricity (Scope 2), and lowering emissions from building materials and construction (Scope 3). Many architecture firms (including LMN) do not yet include the energy use or embodied carbon of their designed buildings in their Scope 3 accounting and claims of carbon neutrality, but there are compelling arguments to do so as this constitutes a vast majority of design firms’ emissions.

Beyond reductions, one idea to address design teams’ Scope 3 embodied carbon is Miller Hull’s Emission Zero program, allocating responsibility for embodied carbon emissions equally among building owner, architect, and contractor. After every effort is made to reduce operational and embodied emissions, remaining emissions are offset through a Green-e certified purchase. Miller Hull pays for their fraction of offsets on all projects, inviting the owner and contractor to do the same, with public transparency on each project’s embodied carbon footprint and details of the offset purchase.

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As an example, LMN’s office emissions (600 tCO2e annually, which includes energy use, supplies, commutes, business travel, and more) are dwarfed by the emissions from embodied carbon and energy use from just one year of design projects.

What are a building’s emissions sources?

Since design teams are responsible for these emissions, we need to understand which aspects of design cause them. To illustrate the various emissions sources, one example project’s cumulative emissions over 60 years are displayed in the tree map (left side).  While emissions vary significantly from project to project, in this example energy use and structural embodied carbon combine for a majority of the total, typical of many buildings.

The right side of the graphic shows the same data, sorted by emissions timeframe. Using timeframe as a lens helps a design team understand opportunities for near-term reductions, also highlighting that many of the emissions are far in the future, with less certainty about their impact.

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60-year carbon emissions can be looked at many ways. The Tree map on the left shows an example project’s relative impacts: a majority is in Operational Energy and structural Embodied Carbon. Looking at total carbon emissions over time (right) allows us to prioritize reductions to meet time-based carbon targets set by the IPCC to reduce the risk of reaching earth’s climate ‘tipping points’ (Post 04). The chart also illustrates that emissions in the future are increasingly uncertain over longer time horizons, another reason to focus on near-term carbon reduction strategies.

The time series shows two more things that impact design teams’ total Scope 3 emissions. First, since over 60% of the US electricity grid is required or pledged to be renewable energy by 2050, still early in the lifetime for any building designed today, operational energy use emissions for electricity trend toward zero. Since this is happening at the utility scale, the only building-scale action necessary to get this reduction is to prioritizing electrification. Second, since structural emissions only happen during initial construction, they are entirely in the purview of the design and construction team. Many project teams are reducing embodied carbon from steel and concrete, and a mass timber building can have very low, or negative, structural emissions.

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A survey of building industry sustainability specialists shows that many emissions types are perceived as important, and even these sustainability specialists identify their knowledge gaps in these areas, weighted form 1-10 based on responses. The 56 respondents include 34 Architects as well as contractors, engineers, and sustainability consultants. Architects’ responses are very similar to overall responses.

Beyond energy use and structural embodied carbon, other emissions sources can be a significant part of a building’s footprint and will be discussed later in the series. We know less about many of these areas, with ongoing research. For example, the MEP 2040 is exploring refrigerants and the embodied carbon of MEP systems, the Pathfinder tool includes the impacts of landscape and hardscape, the forthcoming CARE tool, which compares embodied carbon against operational carbon for building reuse, and the recently released EPIC tool in beta that includes many categories of building emissions.

A survey among sustainability specialists shows where knowledge gaps exist, even among the leaders within the profession. Each of these areas will be covered later in the series as we grapple with reducing our emissions.

Office as Carbon Lab

Even though Architect’s Scope 1 and 2 operational emissions are many times lower than our buildings’ emissions (Scope 3), our offices act as laboratories for experimentation, informing client conversations and emissions reduction strategies.

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We chose our office for a detailed study of interior renovations’ embodied carbon impact. This has helped us become familiar with the relative carbon impact of common interior systems, especially the high impact of carpet, chairs and workstations.

As examples, studying the embodied carbon of our own Scope 1 emissions from our 2015 office remodel inspired articles and the creation of a public-facing interiors embodied carbon toolkit. We have also tested custom post-occupancy data tools on our own office first. Providing custom composting and recycling containers to improve usage rates, requiring sustainable lunch packaging from caterers, lowering energy use with controls, learning the benefits of motorized shades to provide daylight, and other efforts inform our daily conversations with clients, as well as the goals in our 2018 Sustainable Action Plan.

Calculating and reducing our office footprint is also part of exploration: we include business travel, operational energy use, purchasing and printing, employee commutes, waste/recycling/compost, and more using the advanced tabs for more detailed inputs within Berkeley’s CoolClimate Business Calculator. Using this tool, our office has an estimated footprint of around 600 tCO2e annually (pre-pandemic), or around 4 tCO2e per employee. From 2008-2012, we offset our carbon footprint using Bonneville Environmental Foundation, switching in 2013 to Forterra’s Evergreen Carbon Capture program where we plant trees each year that will remove carbon from the atmosphere over 100 years. We are switching away from tree-planting for carbon sequestration, though we haven’t finalized our new plan. This is largely driven by research for this series where we strongly believe now that carbon offsets need to be fully realized over a very short time frame, matched with the time of emissions. We have not yet attempted to update our carbon footprint in the work-from-home era, but some methods exist.


Please email any questions or comments to Kjell Anderson, kanderson@lmnarchitects.com

Thanks to our external collaborators and peer reviewers
Vincent Martinez, Arch 2030; Tate Walker, OPN Architects; Harry Flamm, Stantec

LMN Architects Team
Huma Timurbanga, Justin Schwartzhoff, Jenn Chen, Chris Savage, Andrew Gustin, Kjell Anderson

The text, images and graphics published here should be credited to LMN Architects unless stated otherwise. Permission to distribute, remix, adapt, and build upon the material in any medium or format for noncommercial purposes is granted as long as attribution is given to LMN Architects.


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