More Musings of an Energy Nerd
Buying almost anything—whether an airplane ticket, a circular saw, or a house—results in carbon emissions. That’s why many climate change activists try to spend as little money as possible.
But dollars aren’t a perfect proxy for carbon emissions. Spending $300 for an airplane ticket results in more carbon emissions than spending $300 at your local farmers’ market.
Most green builders don’t want to contribute to climate change. But it’s hard to build a house without buying a lot of stuff: a septic tank, plumbing pipes, a concrete slab, framing lumber, fasteners, sheathing, roofing, Tyvek, windows, siding, insulation, electrical cable, flooring, drywall, a furnace, a ventilation system, bathroom fixtures, and kitchen appliances. Manufacturing each of these items entails carbon emissions. Moreover, there are also carbon emissions associated with material deliveries and commutes to the job site by workers.
The carbon emissions associated with the manufacture and delivery of construction materials are usually referred to as “embodied carbon.” This is a problematic phrase, however, especially in light of the fact that some environmental activists, including authors Bruce King and Chris Magwood, advise builders to sequester large amounts of plant-based carbon (in the form of wood, straw, or similar materials) in new buildings. If you build a straw-bale house, the house will contain a lot of “sequestered carbon”—that’s the straw bales—but (perhaps) relatively low levels of “embodied carbon”—that’s the carbon released into the atmosphere to manufacture the home’s roofing, windows, and kitchen appliances.
Because of the potential confusion between “sequestered carbon” and “embodied carbon,” I propose that we stick to the phrase “embodied carbon emissions” instead of “embodied carbon.”
Bruce King and Chris Magwood’s new book
Bruce King is the author of a 2017 book called The New Carbon Architecture, while Chris…
Weekly Newsletter
Get building science and energy efficiency advice, plus special offers, in your inbox.
This article is only available to GBA Prime Members
Sign up for a free trial and get instant access to this article as well as GBA’s complete library of premium articles and construction details.
Start Free TrialAlready a member? Log in
26 Comments
Excellent article. This is a very important subject, actually a subject of existential importance. Every sincere effort to find solutions, even if mistaken or misguided, should be encouraged. But considering the importance, we also need to look at those efforts with objective skepticism. Martin does a very good job of that here.
That said, I think we also need to keep in mind that we aren't looking for the magic bullet, the one solution that solves all our problems. We've got to draw from every available resource and seek incremental as well as grand solutions.
Our modern way of building, and our building codes, have pushed us over the last 150 years to homogenize our materials across geography. This needs to change. And we need to be getting out of that old habit of thinking in terms of a single solution that works across all geographies. We really need to be maximizing the efficiency of our resource use by localizing our use of materials. We need to be creating delivery infrastructures to make that possible.
For example, it makes no sense to be building homes in New Mexico out of lumber from Oregon. What can we do, for example, in terms of policy, to encourage the use of more adobe construction in NM? It took efforts over decades to reach the point where materials such as adobe were addressed in national codes.
Thank you for addressing the point that a house is more than just walls and a roof. All that other stuff inside reveals the importance that we scale back our consumption habits. How many toilets does a family of 4 really need, assuming they don't all have diarrhea simultaneously? And how big a kitchen? Of course the people selling cabinetry will push us to desire more and more and the banks will be happy to lend us the money.
You raise many good points, especially regarding use of locally sourced materials. Unfortunately the globalized nature of commerce, which is always looking for the cheapest place to manufacture and where there is virtually no cost paid for carbon emmissions, defeats that purpose and adds a huge carbon footprint to so many products.
To illustrate this, imagine a typical piece of furniture. A log is cut in British Columbia and shipped to Oregon where it is turned into lumber. The lumber is shipped to a large distributor in China who then forwards it to Viet Nam where it is made into a piece of furniture. The furniture is then shipped back to Vancouver and sold to the very guy who cut the tree down.....Meanwhile the small furniture maker in the town next door is out of business because he can't compete with $2.00 hr wages in Viet Nam....The result is a society that craves vast quantities of cheap, poorly made stuff at a huge carbon cost.
Ann Edminster's retort is even harder to challenge when you add in the infrastructure that goes along with developing new housing (roads, bridges, water and sewer or wells and septic, telecom, schools, hospitals and malls) -none of which lends itself to agribuilding materials. Meanwhile vast stretches of inner city or close in areas areas with existing infrastructure (including public transit) are left to rot due to socio-economic forces and many of these areas have witnessed a net outflow of population over the last 50 years. Perhaps new construction should be focused on these areas first and foremost.
Very interesting article Martin.
Though I'm certainly left wondering what we should think the path forward is. Or maybe the point is that we should just accept pessimism and go quietly into the night...
Does anyone else see the inherent conflict with the 'do nothing' approach? It presupposes that in the future, we will have reduced operating emissions compared to now. But how will that be if we cannot invest the capital (in all the meaning of that word) to make a transition to that system? Is the idea that we should do nothing now, and continue to do nothing into the future? So have less kids, let our infrastructure crumble, be as sedentary as possible. But then we will need to farm. And with labor intensive processes, perhaps we will need more kids again...
I guess it all just feels like a circular firing squad sometimes. Perhaps I don't fully comprehend this notion:
"Since embodied carbon emissions happen before construction begins, they represent emissions that are released into our atmosphere right now, when the planet is at a dangerous tipping point. Unlike operational CO2 emissions, which are spread out over decades, large quantities of “front-loaded” emissions may tilt the climate into irreversible warming."
Can this not just as easily happen later, in perhaps 20 years, after we're 'done doing nothing'?
This is not a jab at your book review Martin-- in fact your review does an excellent job of highlighting this tension. I guess I am in a bit of despair as to the way forward. Sometimes I think we just need to push through and get our systems upgraded (but still shooting for the lowest embodied carbon emissions in the process) and deal with the future consequences, which may be inevitable anyways. Push the head through, if you will, and the body comes easily.
Maine,
I don't have answers to your questions. But if those of us who live comfortable lives in North America were ethically and philosophically consistent, we would strive for simplicity, reducing our luxuries at whatever pace feels comfortable to us.
If we took those steps, it wouldn't be "doing nothing." It would be doing something.
That's fair Martin. We can certainly all consume less. But we still will have to keep warm, eat, and hopefully have access to robust healthcare, emegency infrastructure, etc. We can burn less oil in the existing furnace, but will that get us off oil? Or if we reduce our luxuries enough, perhaps we don't need to...
What becomes difficult is to decide whether we should do 'more' in order to build a better future. 'More' meaning install renewable energy infrastructure, better insulate houses, develop new building products and technologies, etc.-- basically create new economic engines to replace the fossil based ones. Doing this seems like it will inevitably take lots of upfront capital (both monetary and carbon emissions) as a trade for later (supposed) improvements. The alternative appears to be: do the least harm now, but it's unclear to me what kind of future that leads us into. Perhaps there is a middle way that I am glossing over by positioning these options as either/or. In any case, some major shift in the framework seems necessary and inevitable.
Maine,
Changes in our energy infrastructure are essential, and these changes have started. Most of us agree that we have to close our coal-fired generating plants and build more wind turbines, more PV installations, and an improved grid to distribute renewable energy.
When it comes to residential construction, though, we all have to think before we act. Should any of us be building vacation homes for wealthy clients? Do our own homes really need an addition? Can we manage to live in an older home for a few more years instead of building a new custom home?
"Should any of us be building vacation homes for wealthy clients? "
Part of what makes that a hard question is that the people who would consider refusing the work are probably the ones who would do that best at doing the project with low carbon. So opting out and leaving it to builders/designers who don't care about the climate might lead to a worse result.
Charlie,
I agree: These questions are all hard questions.
As you know, Martin, these are the types of questions that have driven me crazy for several decades now, and I'm not closer to resolving the contradictions.
Tyler, I think for me the critical question for anything these days is "when is the carbon payback"? As others have said, this is the worst moment in the history of humans to be dumping carbon into the atmosphere, so unless the payback is very fast, it's a net negative.
I also don't have any answers. I am starting to focus more on resilience, on preparing houses for a difficult and unpredictable future as best we can.
Dan,
Code-minimum housing, with each room as small as possible, is the new green.
Barely meet code. Forget the thick insulation and triple-glazed windows.
"Code-minimum housing, with each room as small as possible, is the new green."
Wow, quite a statement!
Why didn't you include that in your 'what's changed in green building' article?
Dan,
I suppose I don't understand why right NOW is the worst time to be dumping carbon into the atmosphere. Couldn't it be in 20 years when total emissions has perhaps doubled? I know there is science about 'tipping points' but I can't say I'm educated on the matter enough to make calls about what that really means. My sense is that we're pretty bad at accurately predicting such complex tipping points.
So don't we need to shift into an entire new watershed-- a new paradigm? Does making such a shift not cost upfront emissions?
Re renewables: I'm not against them, but I think we need to be honest about how they've come to be ('capitalism and progress) i.e. lots of upfront costs. And the grid scale shift towards them will cost us a lot more as well. It's more than just standing solar panels up in fields.
Maine Tyler,
Q. "'Code-minimum housing, with each room as small as possible, is the new green.' Wow, quite a statement! Why didn't you include that in your 'What's Changed in Green Building' article?"
A. I did, somewhat obliquely. In my article ("Green Building Has Changed"), I wrote: "Our understanding of green building principles has changed due to improvements in ... understanding. Here are some examples: ... [Now there is] A new focus on embodied carbon. If you are a green builder, you can’t ignore embodied carbon any more—a topic that barely deserved a mention back in 2008."
It's a big topic, worthy of several in-depth articles. GBA has been delving into the embodied energy issue for many years.
Back in 2018 (in an article titled "Carbon Emissions By the Construction Industry"), I wrote:
"If you care about embodied energy: (1) Don’t build any new buildings.
(2) If you must build a new building, use the shantytowns and favelas of the Third World as your model. The best way to build a new building is with materials scavenged from your local dump."
Maine Tyler,
Q. "I suppose I don't understand why right NOW is the worst time to be dumping carbon into the atmosphere. Couldn't it be in 20 years when total emissions has perhaps doubled?"
A. I fervently hope that total carbon emissions don't double in 20 years. If they do, the collapse of civilization will be quite rapid.
If green builders aren't operating on the assumption that we need to start RIGHT NOW to bend the curve of carbon emissions downward, we're not all on the same page. And, unfortunately, we're doomed.
Response to Tyler, #17: "History" is in the past. There has been no point since humans started roaming the earth that it has been more urgent to slow carbon emissions than it is today.
Unfortunately it will almost certainly be even more urgent in 20 years, but that's the future, not history. At that point, we can look back at today as a historical moment when we still had the chance to make a difference but chose not to because it was too difficult (or because we'd rather argue about semantics).
response to Martin #19, and Michael #21
To be clear, I'm not at all suggesting we don't urgently start work on this now.
My '20 years from now' comment is simply to question whether the simple 'payback' analysis is the best metric. I also question how accurately we're able to make many of these payback analyses, especially as we look into the nearish future to an energy grid that we don't quite know how it will operate (e.g. demand management).
I'm not entirely convinced that simply consuming less within the existing systems paradigm is enough to get us over the needed 'humps.' I wonder if we will need to 'spend' a bit to get us over. I am, in part, defending the work of the likes of these authors. Hydrogen, for example, may be a distraction from real solutions at this very moment, but I don't know that that means it won't be very necessary in the future (therefore making research into it NOW worthwhile-- maybe).
The equation is different for every action. Some things, like insulating walls to R-100, obviously will never make sense. But the notion that we ought to take whatever actions CURRENTLY produce the least amount of carbon emissions right NOW is not a notion I completely buy, for the above reasons. But to be clear, I'm not advocating for ignoring embodied carbon emissions-- quite the opposite. I'm just saying the equation is multi-variable with a time function and lots of unknowns. (shrug)
The economy-wide transition to renewables strikes me as one example of this investing in the future tradeoff. Not because an individual solar panel has that long of a pay-back, but because a systems-wide transition will costs a lot in infrastructure changes-- batteries, upgraded grids, electric vehicle infrastructure to replace the ICE, new recycling infrastructure-- the list goes on). Not to mention that the very existence of affordable solar has been made possible by massive growth-based and exploitative (materials and labor) economies.
I think we need to thread the needle between these 'investments' and the 'reductions.'
Maine Tyler,
I completely agree with you that "the equation is multi-variable with a time function and lots of unknowns." Humility is in order.
That said, I'll make another attempt to respond to your statement that "I don't understand why right NOW is the worst time to be dumping carbon into the atmosphere."
At some point -- a point that our civilization may be very close to -- the feedback loops that accompany carbon accumulations in the atmosphere become irreversible. With fast warming, lots of carbon that is now locked in permafrost will be released, setting up an accelerating feedback loop. Here's another example of an accelerating feedback loop: in a warming climate, the size of the Arctic ice sheet is reduced. When this happens, white ice (which reflects solar heat) is replaced by black ocean, which absorbs solar heat. This change causes the ocean to warm even faster.
It's still possible that huge chunks of the Greenland ice sheet or the Antarctic ice sheet may suddenly be released, causing a rapid and catastrophic rise in sea level. We all want to prevent that.
These feedback loops are very scary. That's why releases occurring right now are so dangerous. If we can all backpedal a little bit, it's still possible (perhaps) that we can avoid going over the cliff.
Current carbon releases are bringing us close to that point at which rapid changes become irreversible.
Maine:
At the very least we should move society away from wasteful practices that bring us little joy, or are even harmful. A huge percentage of the consumption in America is driven not by need- or even aesthetic concerns- but is habitual/ addictive-driven by relentless 24/7 marketing. Americans buy vast quantities of poorly made products they do not need, that will be landfilled in a very short time and offer very little pleasure beyond a few minutes. I am reminded of this every Christmas watching the mountains of plastic toys that are forgotten by Valentine's Day. Or when I see wealthy people I know who have closets full of clothes that have never been taken out of the wrappers. Or the hoarders who can barely move about their homes due to the volume of "stuff" in the way....
This is a wonderful article Martin, thanks for putting in the time to share your thoughts.
One thing I might add: "Most of these materials require many hours of labor to separate, and have very little economic value." - for NOW. As the cost of energy increases (or our governments come to their senses and impose carbon taxes), they will have more value.
Sukoi,
Of course, if the hand-sorted items pulled from a demotion site -- those items which now have "very little economic value" -- eventually have significant value, that will be a good news/bad news scenario. It would imply that housing just got much, much more expensive -- for all of us.
More to the point, King and Magwood envision a future in which "our carbon-storing material, such as wood, straw, or hemp" can be reused when buildings are demolished after a period of time that they set at 60 years; moreover, they posit that this feat can be "easily done." The idea that 60-year-old straw or hemp will have economic value after being pulled from a house that is being demolished strikes me as highly unlikely.
For sure not "easily done". My point is, we might be wise to design for disassembly (with everything, not just residential construction) as we head into an era of energy descent.
Chris Magwood is also the driving force behind the BEAM calculator, covered in GBA. I think it has far more potential to change the industry than this, or any, book. I encourage everyone to check it out.
Here's the GBA piece - https://www.greenbuildingadvisor.com/article/beam-estimator-for-measuring-embodied-carbon
Dan,
I agree with you that we owe Chris Magwood a debt of gratitude for his work developing the BEAM estimator, which appears to be a very useful tool.
That said, I noted this comment by Michael Maines: "They [Chris Magwood and Jacob Deva Racusin] said there is little to no solid data on embodied carbon of things like plumbing fixtures and electrical wires. They could have used estimates or approximations but decided to stick with the things they have reliable data for, so [with BEAM] you won't get a true accounting of the carbon impact of the entire house, but there are also not a lot of low-carbon options for things like wiring so it's better to focus on the things we can change, such as insulation or foundation types."
The two statements I'm making -- namely, that we owe Chris Magwood a debt of gratitude for creating the BEAM estimator, and that there remain many unanswered questions (many of which I raise in my book review) about the carbon emissions associated with new residential construction -- aren't contradictory.
I am very hopeful after reading the intelligent discussion provoked by your book review. There are reasonable, broadminded people beavering away on issues that affect us all. As always I look forward to your articles and the discussion that follows.
Martin, while it would be great to have a complete picture of the carbon impact of every home in its entirety, since that is currently impossible, having a reasonably accurate tool that compares the relative impact of the things we CAN control is the next best thing. Don't let the perfect be the enemy of the good. We don't have time for that.
Designing and building homes is a tough business for an environmentalist to be in. The market for truly sustainable homes--whether Living Building Challenge-type superhomes, or extremely basic housing as you suggest--is not very large. I am often tempted to leave the industry altogether, but feel confident that houses will continue to be built and that helping people doing a little better than average on a lot of homes is better than not doing anything at all, and the upgrades hopefully make the homes a little more resilient for an uncertain future.
Michael,
As I hope you know, I'm grateful for conscientious designers and builders like you who are struggling with these issues.
We all want a better future, and we all want to build homes that don't damage the environment. Keep up the good work, and keep sharing your thoughts and advice with all of us here at GBA.
Log in or become a member to post a comment.
Sign up Log in