We Must Cut Carbon out of Construction – NOW! / by Sustainable

By Unsplash

By Unsplash

August, 2019

By Paul Dowsett, OAA, FRAIC, LEED AP
Principal Architect — Sustainable. Architecture for a Healthy Planet.


Five months.  That’s all we have to transform as an industry.  Seventeen months if we’re being generous.

And transform we must!  There is no option - or planet - B.

Being an architect, I look at my own industry, to determine the state we’re in, and more importantly, to propose how we can, and must, change.

The act of city building would not be possible without the literal city builders, i.e. the entire construction industry – building owners and managers, architects and engineers, general contractors and tradespeople, and material manufacturers and suppliers.

And when it comes to the climate crisis, all of us as “city builders” have an important role to play.

And that role must change.

We must cut carbon out of construction – NOW !

The emission of carbon dioxide, the most significant greenhouse gas directly affected by human activity, is believed to be a major cause of the climate crisis that we are in. And it has been believed to be so since at least 1912!

As the world has been celebrating the 50th anniversary of Neil Armstrong setting foot on the Moon,  another scientific anniversary, perhaps just as important for the future of civilization, has come around.

While it may not sound as impressive as landing on the Moon, forty years ago, a group of climate scientists gathered at Woods Hole Oceanographic Institution in Massachusetts had the first meeting of the "Ad Hoc Group on Carbon Dioxide and Climate". This led to the preparation of the Charney Report – the first comprehensive assessment of global climate change due to carbon dioxide.

Over the past 40 years, the success of the predictions of this exemplar of good science has firmly established the science of global warming:


Fifty years ago, during the time of the Apollo 11 moon landing, carbon emissions were simply known as “pollution.”

Back then, pollution was seen as an unnecessary problem, which should be stopped.

Today, pollution is still seen as an unnecessary problem, and it should still be stopped.

More importantly, we now know a lot more about the scale and sources of this pollution.

According to the US Environmental Protection Agency: “Carbon dioxide [which represented 82% of US greenhouse gas emissions in 2017] enters the atmosphere through burning fossil fuels (coal, natural gas, and oil), solid waste, trees and other biological materials, and also as a result of certain chemical reactions (e.g., manufacture of cement). Carbon dioxide is removed from the atmosphere (or "sequestered") when it is absorbed by plants as part of the biological carbon cycle.”


“Pollution” from the construction industry looks like this: Massive amounts of carbon dioxide are emitted into the atmosphere during the construction of a building (embodied carbon) and during the lifetime operation of a building (operational carbon).

The thing is, we as a group must do our part to mitigate the climate crisis.

These massive carbon emissions must stop, we as an industry must change, and here’s why and how.

Why we must change

According to a 2017 report by the World Green Building Council (WorldGBC), the global construction industry, which is responsible for 30% of global greenhouse gas (GHG) emissions (roughly equivalent to those of China) must operate at “net zero carbon” by 2050 if global warming is to remain under two degrees Celsius — the limit enshrined in the Paris Agreement.

Not only that, but “Every building on the planet must be ‘net zero carbon’ by 2050 to keep global warming below 2°C” (emphasis mine).

WorldGBC also states that well under 1% of all buildings worldwide are currently net zero, “requiring a  monumental and coordinated effort by businesses, governments and nongovernmental organizations to bring the building sector within striking distance of Paris Agreement targets.” https://www.worldgbc.org/news-media/every-building-planet-must-be-%E2%80%98net-zero-carbon%E2%80%99-2050-keep-global-warming-below-2%C2%B0c-new

In other words, we have to transition rapidly from a world where there are just a few thousand net zero buildings to one where there are billions.

When they say “every building on the planet”, this means every building … whether new and existing.

Further, it is likely that, in 2017, WorldGBC was only considering operational carbon, and not embodied carbon.

Some steps forward

We have to start somewhere, and here’s a start in Canada:

In June, 2019, the Canadian Government announced that a $40-million investment through The Atmospheric Fund [TAF] to create Canada's first “climate centre” in the Greater Toronto area, which is to become one of seven new “low carbon cities” across Canada to reduce pollution and help fight climate change. The plan envisions climate centres that will work with businesses, non-profit organizations, and governments to help create low carbon solutions that focus mainly on creating energy-efficient buildings and local renewable energy projects:


Again, this initiative, is likely only considering operational carbon, and then, only the operational carbon of energy-efficient new buildings. Unfortunately, such buildings only represent a small percentage of the total carbon output of all buildings. Much more carbon is emitted during the construction of new buildings and during the operation of existing buildings.

We must, more urgently, focus our attention on these other areas. How can we transform both the operation of existing buildings, and the construction of new buildings, to emit no carbon?

How we will change — existing buildings and adaptive reuse

First, the case for working with “old” (existing) buildings: We must remember that new buildings only account for about 2% of total building stock annually. At this rate, new, energy-efficient buildings can not replace existing buildings fast enough—and nor should they !

Maintenance and retention of significant buildings and adaptive reuse of generic buildings makes for a much more varied and vibrant cityscape. Old buildings are where new ideas thrive, as Brandon G. Donnelly explains in a blog post for Smart Cities Dive. He writes that, “there is no leeway for such chancy trial, error and experimentation in the high-overhead economy of new construction,” adding this “is why Jane Jacobs famously said that "new ideas need old buildings."” https://www.smartcitiesdive.com/ex/sustainablecitiescollective/new-ideas-need-old-buildings/249976/

There is nothing that we can do to reduce the embodied carbon in existing buildings, as it has already been emitted during construction.

But, we can respect that that carbon has been emitted , and maintain the building’s existing structure by retaining it as-is or transforming it through adaptive reuse. The alternative is to demolish that structure and send its component parts to landfill, only to emit more carbon during the construction of a replacement building.

Further, we can retrofit an existing building so that it is optimally energy-efficient, thus reducing its operational carbon going forward.

A May 2019 blog post from TAF reminds us that, “44 per cent of our region’s carbon emissions now come from buildings.”

TAF then point to a way forward: “TAF and Efficiency Capital are helping building owners seize this opportunity by making it easy to improve energy efficiency and building performance without spending any money upfront.

The rationale for a retrofit is clear. Significant amounts of energy are wasted in large buildings – condos, co-ops, apartments, institutions, and commercial buildings. Cut the waste and you save on energy bills, repairs and maintenance, while increasing your asset value and creating a more comfortable living environment.”


A July 2019 blog post from TAF goes further and tells us that, “One benefit [of retrofit] that does not get a lot of press is the fact that there is no cost to reduce the carbon. Say what, one might ask; how can that be? It costs money to perform an energy retrofit.

But that’s not the right way to look at the situation.” There is a “strong business case for building energy retrofits. They offer strong financial, environmental and social benefits.”


We know that retrofitting existing buildings is urgent, because they are such huge contributors to a city’s GHG emissions. In Toronto, for example, the 2017 TransformTO study reports that,In the baseline year [2011], buildings account for 56% of GHG emissions in the City of Toronto” (p. 26)

Buildings — our sector — were the number one cause of emissions, and caused more than half of the city’s total emissions ! And this is, again, likely only looking at operational carbon:


To reduce operational carbon, in Ontario we could electrify everything — both new and existing buildings. We have one of the most carbon-clean electrical grids on the planet. According to Arborus Consulting:

Grid-delivered electricity in Ontario currently has a much lower annual average carbon intensity of 77 g/kWh. This low carbon intensity is due to the elimination of coal power and the use of nuclear and hydro power to generate most of Ontario’s electricity. With more renewable power coming on line every year — I just checked Gridwatch on a weekday morning in April [2016] and wind was supplying more electricity (11%) than natural gas (5%) — it’s more clear than ever that if the Ontario government wants to reduce carbon emissions in buildings, it will have to encourage the development of low-carbon space heating strategies that do not rely on natural gas.


Sustainable. Architecture for a Healthy Planet has just completed a project that capitalizes on the carbon-cleanliness of Ontario’s electrical grid with an air-tight and well-insulated home that requires 87% less energy to heat, cool, and operate than a conventional home …and the home is all-electric …including the all-electric car:


Other jurisdictions are getting on board with electrification. Berkeley, California, for example, recently became the first US city to ban the installation of natural gas lines in newly constructed single-family, town homes, and small apartment buildings, and requires them to have electric infrastructure instead: https://www.sfchronicle.com/bayarea/article/Berkeley-becomes-first-U-S-city-to-ban-natural-14102242.php

Embodied carbon is becoming significant

We’re catching on to the idea that embodied carbon is significant, especially as we develop more and more energy-efficient buildings. Using “energy” as a proxy for “carbon”, BuildingGreen summarizes that:

“Almost all the attention paid to energy conservation in buildings has focused on reducing their operating energy. Given the energy hogs that many buildings were (and are), this focus is appropriate. As builders and architects succeed in making their buildings more efficient, however, the energy used to build buildings starts to look significant. This embodied energy can add up to many years’ worth of operating energy in an efficient building (see table [in the article]). While taking steps to reduce operating energy is clearly the first priority, it makes sense to look for options that minimize the initial energy investment—the embodied energy—as well.”


Regarding the term “embodied carbon”, I appreciate Lloyd Alter’s blog post in Treehugger, where he outlines that he is not a fan of the term (because it hides the urgent need to deal with the carbon that is emitted as a result of the construction process). Instead, he suggests we all use “"upfront carbon emissions" (UCE) because that's what they are.”


Looking directly at the article referenced by Lloyd in his post — Anthony Pak’s article published in Canadian Architect — reveals that:

Embodied carbon [will be] on par with operational carbon emissions over the span of the next three decades. So if you are designing green buildings with the idea that you are saving the planet, but you don’t consider embodied carbon, you are missing half of the equation.” https://www.canadianarchitect.com/embodied-carbon-the-blindspot-of-the-buildings-industry/

My colleague, Mike Mazurkiewicz, responds with,More than just "half" the equation - the half that matters today, not over the next 30 years.”

Mike is completing his Masters in Architecture at Ryerson University with a thesis that includes the study of the carbon importance of building materials. Not surprisingly, he has found that the earlier that carbon is emitted in the life of a building, the greater its negative impact.

Mike agrees with Anthony, who states that, The importance of embodied carbon becomes even more evident when you consider that, according to the IPCC, to limit global warming to 1.5°C, carbon emissions would need to peak next year in 2020 and then go to net zero globally by 2050. Given that embodied carbon will make up almost half of total new construction emissions between now and 2050, we cannot ignore embodied carbon if we want to have any chance of hitting our climate targets.” (emphasis mine)


2020 is 5 months from now — 5 months to peak our global carbon emissions !

(17 months if we’re being generous and giving ourselves to the end of next year.)

What we cannot ignore any longer is that the manufacturing processes for concrete, steel, and asphalt — the assumed inevitable foundations of our construction industry — are huge emitters of carbon.

Writing in The Guardian, Jonathan Watts calls concrete, “the most destructive material on earth”.

“If the cement industry were a country,” he writes, “ it would be the third largest carbon dioxide emitter in the world with up to 2.8bn tonnes, surpassed only by China and the US.” https://www.theguardian.com/cities/2019/feb/25/concrete-the-most-destructive-material-on-earth


What to use instead ?

According to The Economist, a viable alternative to concrete and steel is wood:

The [Three Little Pigs] fairy tale could have been written by a flack for the construction industry, which strongly favours brick, concrete and steel. However, in the real world it would help reduce pollution and slow global warming if more builders copied the wood-loving second pig.”

“But no other building material has environmental credentials as exciting and overlooked as wood.” https://www.economist.com/leaders/2019/01/05/why-more-buildings-should-be-made-of-wood

A forest — the “wood factory” if you will — is a carbon-sink, drawing down carbon from the atmosphere, and moving us in the right direction with our carbon emissions. According to Project Drawdown, which cites a 2014 study,Building with wood could reduce annual global emissions of carbon dioxide by 14 to 31 percent.


The construction industry can, and must, change

But getting the designers and builders in the construction industry to convince the concrete, steel, and asphalt industries to give up their predominant position will be on par with getting the petroleum industry to give up theirs. They are all big, and powerful, and not terribly willing to change.

But there is hope !

I am encouraged by a recent LinkedIn post of Andrew Bowerbank, National Vice President, Sustainability & Energy at WSP in Canada, where Andrew states, “Now this is the low carbon leadership that the global construction industry should aspire to. Skanska is the world's largest construction firm. If they can commit to 100% Zero carbon by 2045, there is no reason why the rest of the industry cannot as well. No more excuses. Lets get on with it.”

This Skanska promo piece encourages us to: “Think of a world where fantastic buildings ...are created ...giving [people] great places to live and work in, and where the CO2 impact during construction is ...well, there isn’t one. That would be a future we could really look forward to.”


Yet, in response to Andrew’s post, Randy Tyrrell, Environmental Entrepreneur, asks, “Great that they established the commitment, but why do they need 25 years to implement? IPCC says we only have 11 years to mitigate in order to avoid catastrophic climate change. I hope more constructors are on board and move faster. How much of the industry would you say are headed to zero carbon and when?”

Clearly, there is much to be done.


Attention: city REbuilders !

On this 50th anniversary of the Apollo moon landing, I am reminded of JFK’s 1962 speech at Rice University:

We choose to go to the Moon in this decade and do the other things, not because they are easy, but because they are hard; because that goal will serve to organize and measure the best of our energies and skills, because that challenge is one that we are willing to accept, one we are unwilling to postpone, and one we intend to win …”

To blatantly rephrase,

We, the entire construction industry, choose to bring carbon to zero in this decade and do the other things, not because they are easy, but because they are hard; because that goal will serve to organize and measure the best of our energies and skills, because that challenge is one that we are willing to accept, one we are unwilling to postpone, and one we intend to win …

Do we as a society accept this challenge ?
Are we unwilling to postpone it ?
Do we intend to win ?

Choosing to bring the embodied and operational carbon of buildings to zero is hard, and it is also necessary for our survival.

I will do my part.

Will you do yours ?


We must embark on a program of city REbuilding, and we must do it now !

I am further encouraged by another recent LinkedIn post by Andrew Bowerbank:

It’s amazing how cities and States in the US have taken up the leadership towards a low carbon economy. 

This is a key factor about political leadership that is true in Canada and the US; as one level of government shifts focus and responsibilities, the others find ways to step into the leadership role. In Canada, it is now the time of the city and municipality. As New York, LA, Seattle, San Francisco, and others take up the climate change charge in the US, Toronto, Vancouver, and others (supported by the Federation of Canadian Municipalities) are driving the charge in Canada. 

We will get this done, we have too.”

Andrew referenced this article from the LA Times:

Just last month, the Toronto Star published an article titled Undeniable—Climate Change Canada—What we can do now:

It is time for all of us to do something. And to do it now.

Medium writer Marta Brzosko says it best: We are all on this sinking ship together — and we are afraid. That’s only natural. But this is precisely why it’s the time to find courage. The courage for acting and speaking about the climate crisis, no matter how uncomfortable it may be. Because, as Greta Thunberg says, our house is on fire. And to ignore the fact that your own house is burning is just ridiculous.” https://link.medium.com/ruVUDY8ewY

I’ll leave you with one last thought, from First Dog on the Moon over at The Guardian:

“If you act now you can maybe avoid the worst of climate change. But you know you're not going to.”


Or will you?