2021 in Review: The Year Embodied Carbon Finally Had a Real Impact

Here are the highlights of our coverage on all things carbon from the year.

high rise building in Singapore covered with lush vertical gardens

Naomi Rahim / Getty Images

November 11, 2021, may be remembered as one of the most important dates in the history of architecture: It was the day the British government finally well and truly killed the Tulip—the restaurant-on-a-stick designed by Foster and Partners that we called the poster child for unsustainable design.

The reasons given for the cancellation:

"Although considerable efforts have been made to adopt all available sustainability techniques to make the construction and operation of the scheme as sustainable as possible, fulfilling the brief with a tall, reinforced concrete lift shaft, would result in a scheme with very high embodied energy and an unsustainable whole life-cycle."

It's no longer enough to be "BREAAM Outstanding" just as it is no longer enough to be LEED Platinum—the definitions of green have changed. Embodied carbon suddenly matters, as does sufficiency. Essentially, the mayor and the inspector concluded that nobody really needed this thing.

As Joe Giddings of the Architects Climate Action Network (and a pioneer in the discussion of embodied carbon) notes in The Architects' Journal: "The bigger picture is that this sets a vitally important precedent for future decisions to be made on the grounds of embodied carbon. Huge moment!"

The building failed to meet what I call my "Four Radical Rules of Design" for the climate revolution:

  • Radical Decarbonization: Design to minimize Upfront Carbon Emissions and eliminate operating carbon emissions.
  • Radical Sufficiency: Design the minimum to do the job, what we actually need, what is enough.
  • Radical Simplicity: Design to use as little material as possible, whatever it is.
  • Radical Efficiency: Design to use as little energy as possible, whatever the source.

These four principles are the lenses through which I look at everything now. Does a project have low upfront and operating carbon? Do we need it at all? Is it designed as simple as it could be, using as little material as possible? And even if it is powered by sunshine, does it use as little as possible? This will come up a lot in our review of the year and in future posts.

What's the Right Way to Build in a Climate Crisis?

Passivhaus townhouses in Goldsmith Street
Walkable affordable Passivhaus townhouses in Goldsmith Street.

Tim Crocker / RIBA

After getting cranky about a pie in the sky project by architects who should know better, I wondered: If one accepts that we are truly in a carbon crisis and have to change the way we build right now, what would be the best way to build? What is the right thing to do? How should we plan our communities? Build our buildings? Get around between them?

I suggested we have to build at the right density to support low-carbon modes of transportation (bikes and feet). Then we have to build at the right height—"anything below two stories and housing isn’t dense enough, anything much over five and it becomes too resource-intensive"—and of the right materials (out of sunshine), to the right standards (Passivhaus). I concluded:

"At about the same time as I was stewing about the Urban Sequoia, the roads and rails that tie Canada together were being washed away in an unprecedented flood caused by an atmospheric river. This is serious, and it is happening now. Climate change is not waiting for 2050 or even 2030. This is why I have no stomach for future fantasies. We can do all this now. We can do zero-carbon without a net. We know how to plan it, we know how to build it, and we know how to get around in it. And we have run out of time."

Transport and Building Emissions Are Not Separate—They Are 'Built Environment Emissions'

Emissions by sector

Architecture 2030

I am tired of pie—or at least this particular pie chart and those like it that separate building emissions from transportation emissions. As transportation consultant Jarett Walker put it, “Land use and transportation are the same thing described in different languages.”

Or as I wrote in my book: "It is not a chicken-and-egg, a which came first thing. It is a single entity or system that has evolved and expanded over the years through the changes in the form of energy available, and in particular the ever-increasing availability and reduction in the cost of fossil fuels."

In this post I propose that we stop thinking about them as separate things, concluding: "We have to stop talking about transportation emissions as something detached from building emissions. What we design and build determines how we get around (and vice versa) and you cannot separate the two. They are all Built Environment Emissions, and we have to deal with them together."

Instead of Asking How We Build, We Should Be Asking Why

Carbon reduction curve

Green Construction Board

The most important article I read this year was by designer and builder Andy Simmonds and Irish journalist Lenny Antonelli, titled "Seeing the wood for the trees - Placing ecology at the heart of construction." Where I am usually just trying to explain embodied carbon, they say it is just the beginning.

"Switching from energy and carbon intensive materials to timber and other natural fibres must be just the starting point, rather than the end point, of our journey to explore ever more ecological ways of creating and refurbishing buildings. Beyond the concepts of ‘up front’ and ‘embodied’ carbon, we must develop our understanding of the land-footprint of the resources we use, and their wider impact on the living world."

They go on to discuss sufficiency, simplicity, the circular economy, and efficiency, but talk about material efficiency:

"Use natural resources extracted from our shared biosphere respectfully and efficiently to substitute for higher embodied carbon materials. Use as few materials as possible to achieve the design. Using a “renewable” material inefficiently, whether to ‘develop the market’ or ‘store carbon’ is wrongheaded – efficient use of the same quantity of material, substituting for higher carbon options across many projects, makes far more sense."

You can read my discussion of their article, "Instead of Asking How We Build, We Should Be Asking Why" but honestly, your time would be better spent reading the original article on Passive House Plus.

Why We Have to Start Considering Organizational Carbon Emissions

Kendeda Building
Kendeda Building in Atlanta.

Lloyd Alter

There are a lot of lessons about how we work that have come out of the pandemic. Lord Aeck Sargent (LAS), one of the architecture firms behind the Kendeda Building in Atlanta, learned a big one: How you run a business has a big effect on how much carbon it emits.

The firm has been monitoring its own emissions since 2007 and did a study during the first half-year of the pandemic. It wrote: "The goal of this analysis was to look beyond the typical 'business as usual’ carbon accounting, using this disruption to better understand the key underlying factors driving operational emissions in order to provide data to prioritize improvements as we begin to transition to a post-COVID-19-era ‘new normal.’"

The results were surprising:

"The calculated carbon emissions avoided during the first six months of the COVID-19 shutdown in 2020, compared to the same six-month period in 2019, totaled 10,513 metric tons of Carbon Dioxide equivalent emissions. That is the equivalent of more than 26 million miles driven in an average passenger vehicle."

This is a huge amount of carbon that is released, just from running the business. I noted we now have to think about this—how we operate our businesses. I called it the organizational carbon emissions.

"In our buildings, we have had the upfront or embodied carbon emissions from creating a building and the operating carbon emissions from running it. Now, we have a number for what might be called the organizational carbon emissions, which are a direct result of how we organize our businesses and the choices we make in how we run them—and it's huge. We are basically learning the carbon footprint of the corporate culture. ... And now that we can see the true organizational carbon footprint that comes from the choices that are made about how we run our organizations, we have to face the fact that there can be no return to business as previously usual."

A New Way for the Housebuilding Industry to Look at Embodied Carbon

Carbon Use Intensity
Carbon Use Intensity.

Builders for Climate Action

While embodied carbon may be getting a tiny bit of attention from architects and the commercial construction industry, homebuilders have probably never heard of it. They are still working with building codes that regulate operating energy efficiency and haven't noticed that we have a carbon crisis, not an energy crisis.

Embodied carbon is hard to define and explain, and probably harder to regulate. A Canadian report issued by Natural Resources Canada, "Achieving Real Net-Zero Emission Homes," is the best stab at it that I have seen to date. It comes up with a new metric to measure it by:

"The Carbon Use Intensity metric would enable more accurate accounting for [greenhouse gas emissions] from the homebuilding sector, and would also allow for regionally appropriate ways to reach CUI targets. In those jurisdictions with available clean electricity, the focus for improving CUI would be more weighted to material emissions, while in jurisdictions with emissions-intensive energy sources, CUI reductions could be achieved by addressing material and operational emissions in conjunction. "

So, in Vermont, with its clean renewable electricity, you would concentrate on lowering the material carbon emissions. In coal-fired Wyoming, you'd focus on the operational carbon emissions. I have not seen another model that takes such a big-picture view of the full carbon problem.

Architects Declare Issues Handbook for Regenerative Design

Cover of practice guide

Architects Declare

I teach sustainable design at Toronto's Ryerson University, and there are not a lot of books I can recommend to my students in such a rapidly changing world. This year I will be able to give them this guide from the United Kingdom-based organization Architects Declare, which writes:

"For everyone working in construction and the built environment sector, meeting the needs of our societies within the earth’s ecological boundaries will demand a paradigm shift in practice. If we are to reduce and eventually reverse the environmental damage we are causing, we will need to re-imagine our buildings, cities and infrastructures as indivisible components of a larger, constantly regenerating, and self-sustaining system."

The first part of the guide is about running a practice, but the second half is sustainable—or I should say regenerative—gold that gets into detail on:

  • Energy, whole live carbon, and circularity
  • Embodied carbon
  • Circularity and waste
  • Retrofit
  • Materials
  • Operational energy and carbon
  • Low energy services and renewables

It is written for architects, but it is good reading for anyone who wants to learn about regenerative design. Download it here.

Other Stories of Interest

Actions to a net zero future


The cement and concrete industries see the writing on the wall about embodied carbon and, to their credit, are seriously trying to clean up their act. The American Cement and Concrete Industry Released Road Map to Carbon Neutrality and the Global Concrete Industry Released Road Map to Net-Zero Carbon both came with a couple of cubic yards of wishful thinking. This conclusion applied to both road maps:

"It's pretty clear that we are always going to need concrete, and the concrete we use will get progressively better. But in the end, it is pretty hard to change the chemical fact of life, that making cement releases a lot of CO2, and the only way to deal with that appears to be to suck the CO2 out of the flue with carbon capture and storage, which doesn't currently exist. and we can't wait to find out if it will. So it is a great road map, but it is driving us on to a long diversion. We have to use a lot less cement and concrete starting right now."

Meanwhile, architect Joe Giddings had another suggestion, comparing buildings to food: "Plant-based options proliferate in supermarkets. The vegan sausage roll has been a sensation for Greggs [a UK chain]. Meat-free Mondays and Veganuary tempt the uninitiated into temporary abstinence. When it comes to culinary preferences and, increasingly, sartorial too, there is widespread understanding that ‘plant-based’ tends to mean better for the environment." He says "It's Time to Put Our Buildings on a Plant-Based Diet too."

Carl Larsson windows in 1894
Blomsterfönstret, 1894.

Carl Larsson

Finally, writing a post about the importance of windows based on a Swedish study, I fell in love with the paintings of Carl Larsson, and illustrated the post with them: "Windows Deliver a Lot More than Just Light and Air."

"Windows represent an enjoyment of the home and fulfill much more than physical needs. They must allow sufficient personal control over fresh and cool air, sound, sunlight, streetlighting and privacy."