The Carbon Balancing Act: Let’s Debunk Greenwashing

by Kjell Anderson 
Director of Sustainable Design at LMN Architects

Zero carbon claims abound. Some have been called out as greenwashing, and nearly all of them should be. Nearly all zero carbon claims omit highlighting their limited scope.

Simply put, the industry hasn’t had the data in many areas to know the embodied and operational carbon emissions impact, so claims omit important scope and attempt to declare victory when the finish line is far away. (Many claims also rely on offsets that may not meaningfully fulfill their goal). Just because we can’t easily quantify an impact doesn’t mean it doesn’t exist. For example, the embodied carbon of MEP systems, perhaps 10-15% of total embodied carbon, is often omitted from carbon neutrality claims, along with furniture and equipment. We finally have the data to begin looking at carbon comprehensively, though with significant areas of uncertainty.

Most firms recognize this problem, of course, but our industry needs to get better at honesty and rigor in our claims. Questionable claims crowd out the hard work we are all doing to get us toward carbon neutrality. And we need to all get there to be effective.

LMN’s response has been the Path To Zero Carbon, a fail-forward series of 16 public posts based on engaging experts across the industry, outlining a broader scope of carbon impacts that need to be addressed to reach carbon neutrality. We began this exploration for several reasons beyond assessing carbon claims: 1) certifications titled Zero Carbon do not address all carbon emissions 2) we are updating our Sustainability Action Plan and need to understand areas to focus on. 3) our industry needs to reduce impacts, lessening our dependence on carbon offsets to claim zero carbon.

The Carbon Leadership Forum, député européen 2040, SE 2050, and many others are leading the way with research into specific topics. The PTZC attempts to distill the best, current data and resources across these major carbon emission sources in the built environment so we can understand the carbon solutions broadly and begin to make informed carbon reductions and understand tradeoffs and consequences.

And carbon emissions are very interrelated among building systems. For example, window to wall ratio (WWR) not only increases energy use directly, but high WWR also increases peak cooling loads that in turn increase the size of mechanical system and associated embodied carbon and refrigerant use and replacement for decades to come; high WWR also eliminates some efficient mechanical systems from being considered; high peak loads due to high WWR also increases demand on the energy grid at the worst times, requiring additional fossil fuel peaker power plants to be built (along with their embodied carbon) but rarely used, increasing energy costs for everyone; high WWR ratio also reduces thermal comfort that often leads to increased HVAC energy use due to complaints triggering set point changes. The series attempts to understand these interrelated effects within a single carbon framework, from circular economy to sitework.

The Path to Zero Carbon

Steps to Address Essential Carbon Impacts

Posts 1-8 frame the questions, responsibilities et challenges and provide fundamentals of climate science, risk and time, as well as primers on energy use carbon, carbone incorporé, et carbon sequestration.

Posts 9-16 cover topics within the design and construction industry. Starting with the Circular Economy et Existing Building decarbonization, the series then covers Structure, Envelopes, and then Hourly and Forward-Looking Energy Use Carbon. Posts on MEP Systems and Beyond the Building are forthcoming.

Primary actions we’ve learned so far:

  1. All firms should understand the top 10 embodied carbon materials and them on all projects. This is becoming a standard of care for architects and contractors in Seattle and other areas. CLF hubs are a great resource for 101 and grad-level embodied carbon reductions. Product selection and Specifications are primary tools.
  2. All firms should understand and reduce operational energy use on all projects. For complex projects, early energy modeling from the engineering side can drive cost-effective energy use reductions that are carbon reductions. Bonus points for using grid-interactive strategies to reduce peak loads.
  3. With rapid adoption and mandates for renewables, electricity nationally has reduced carbon emissions by 25% over the last decade. Long-lived assets like buildings will reap the carbon benefit as renewables scale and drive all-electric, efficient heat pump buildings near zero carbon from energy use by 2050, still early life for any building designed or renovated today.
  4. Rejoins circular economy. Buildings, products, and materials can all be reused and recycled if they are designed for deconstruction. Allowing time for deconstruction, finding and specifying salvaged materials, and engaging in deep energy retrofits to breathe new life into old buildings are key strategies.
  5. Choose honesty over hype! We can’t get to zero as individuals, only by working across our entire sector.


Kjell Anderson, AIA, CSBA, LEED Fellow, is LMN’s Director of Sustainable Design and leader of LMN’s Green Team, spearheading initiatives into energy modeling, materials + health, and water use reductions. He is the author of Design Energy Simulation for Architects, published by Routledge in 2014. He initiated and convened the Seattle Regional Hub of the Carbon Leadership Forum in November 2019.

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