[Gifted article link, good for 7 days] My modification to the title. This is an essential long read about concrete and it's most important ingredient, Portland cement. Concrete is the key building...
[Gifted article link, good for 7 days]
My modification to the title. This is an essential long read about concrete and it's most important ingredient, Portland cement.
Concrete is the key building material for modernity. Concrete's history, manufacture, carbon costs, economic impacts, engineering, distribution, and ever-growing uses have been significant contributors to climate-changing emissions.
Future developments in reengineering concrete's material composition, recycling, carbon capture during recycling, and other measures will be key to climate mitigation.
I'm absolutely agreed; this is super important! That said -- and I apologize for doing so -- I skimmed the sections which attempted to weave an emotional story about the damage that climate change...
I'm absolutely agreed; this is super important! That said -- and I apologize for doing so -- I skimmed the sections which attempted to weave an emotional story about the damage that climate change wrecks upon the world's least fortunate, and focused directly on the science.
Here're my thoughts on the article!
Almost every building erected in the past 75 years in an industrialized country has, at the least, a concrete foundation and, very likely, concrete floors.
There are robust, well tested alternatives! We've had permanent wood foundations (PWFs) since the 70s (example new construction a building science/marketing channel), and there are several approaches to avoiding putting in concrete floors (crawlspaces are an obvious one, which also have the benefit of making building utility repairs dramatically easier!). We even know how to build multi-storey buildings with only concrete in their foundations (example for up to six in Vancouver); one can imagine subbing in PWFs for those situations would be feasible, if potentially nerve wracking for the structural engineer of record.
[wind turbines, concrete in manufacturing plants, pipes, etc.]
The overarching fact about concrete is that it’s unavoidable. And the more it’s used, the more its use expands. Concrete is the material that networks almost every other built network.
Disagreed! I think that we've lacked the financial incentive to think outside the box in many fields, but that alternatives are clearly possible. In many cases, I'd imagine that fibreglass-reinforced plastics could take the place of concrete directly (e.g. wind turbines do this already), and in others, a thin concrete liner could provide chemical and wear resistance to an otherwise primarily plastic pipe (e.g. water transport). Manufacturing plants also needn't use concrete -- we did just fine with wood block floors for ages until concrete (as the article notes) became cost effective enough to replace it. Even dams can have their concrete usage dropped dramatically (for context, concrete is only necessary on the face of that retention structure; the rest of it is just plastic webbing and whatnot)
There are always going to be situations where concrete is absolutely necessary, but I would hazard that it's dramatically fewer than the places we use it today.
Bermejo pointed out that carbon emissions don’t come only from construction materials. For most buildings the majority of emissions result from running the facility — heating it, cooling it, lighting it — over time. The built environment accounts for about 40% of global carbon emissions, with 13% generated by erecting and repairing structures and the rest from their ongoing use.
Ooh, yeah, the journalist should've caught that. They're comparing operational vs. embodied carbon, and that person is using a very motivated definition of "most" buildings. If folks are interested I can try to track down some old stats I was seeing, but afaik -- under modern building codes (for residential construction, at least), improvements to factors affecting operational efficiency (i.e. insulating, making improved windows, air sealing, modernizing HVAC, etc.) have effectively moved the target to embodied carbon, not away. I'd imagine that the executive who runs a company which produces the material responsible for ~36% ([1]) of a typical residential building's embodied carbon would have some motivation for getting ahead of criticism 😅
There are some serious limits on the substitutability of wood for concrete, though. You can build six-story timber frames, but not dense urban skyscrapers, roads, or massive dams, bridges, and...
There are some serious limits on the substitutability of wood for concrete, though. You can build six-story timber frames, but not dense urban skyscrapers, roads, or massive dams, bridges, and subterranean infrastructure. I've seen those solid wood factory floors, and the modern cost would be astronomical given how few large-diameter hardwood trees are left. Fire-retardant technology has gotten better, there's research on silicated wood treatments that might resist wet conditions more effectively, but wood still won't make up more than a fraction of concrete applications.
I'm not saying we can't substitute a fair amount of concrete, though. For housing, adobe, rammed earth, modular panels, bamboo, and other solutions can still support fair density and lower environmental impact. Provided that they're chosen appropriately for local availability and conditions.
The article also mentions the risks from clear-cutting trees - damaging CO2 and methane emissions from exposed decaying forest floor materials.
Oh absolutely! To put my point more precisely: the most carbon efficient yard of concrete is the one we didn't use, so putting effort into reducing utilization is often a huge bang for the buck....
There are some serious limits on the substitutability of wood for concrete, though.
Oh absolutely! To put my point more precisely: the most carbon efficient yard of concrete is the one we didn't use, so putting effort into reducing utilization is often a huge bang for the buck. In effectively every sense I do not see things as binaries, so I'm not proposing that the world can go "concrete-free" at the drop of the hat -- only that there's likely a lot of low hanging fruit by thinking about alternatives in end-uses, as opposed to pursuing diminishing returns surrounding CO2e reduction in concrete production.
I won't go point by point, since I don't think we're having like a debate or anything, but wood's good to 18 stories with mass timber (the structural system is mostly timber, but there's definitely concrete and steel in there playing supporting roles), and the floors mentioned don't use large diameter wood anyhow -- it's often 4x4's or 6x6's, and there's no compelling reason to keep 'em wood (they're still making them out of SYP, which is very much not old growth in 2026). Anything cellulostic with roughly the same material properties (i.e. endgrain is tough, can be sealed with oil) should behave similarly, too. Some industrial wood block flooring companies already do so with (seemingly) wood-plastic composites!
I've seen those solid wood factory floors [...]
That's really cool! I think they're all out east, effectively, and I've never had a chance to see one in person. There're a few public spaces which have 'em and they've held up great, though!
[...] but wood still won't make up more than a fraction of concrete applications.
Yeah I think that's where I would love to have more info? I threw a very cursory look into this, and turned up this dubious report. Taking their numbers with a grain of salt, it sounds like ~43% of cement usage is in roads/bridges, ~28% are residential, and 19% is "non-residential demand" (presumably, commercial/industrial, but the article frames it as "AI datacentres"). Even if we pretend that the 43% is untouchable (dubious IMO but perhaps there's a civil engineer around who could dig in further), that leaves another ~47% which could be meaningfully addressed by reducing concrete usage. For instance, it seems like AI datacentres are mostly one storey (just based on vibes, since searching it always turns up images like this one), which could easily be built without any concrete: gravity loads seem low enough to be handled with some of the plywood-on-grade flooring options, and if it's one storey, wood framing it (maybe with trusses to get decent enough clear spans for racks) seems very plausible.
I'm not saying we can't substitute a fair amount of concrete, though.
🤦 apologies, I appear to have skipped this sentence before writing the above response. I suppose it still applies, but please consider it moreso a soft push instead of the hard counterpoint I had originally penned.
The article also mentions the risks from clear-cutting trees - damaging CO2 and methane emissions from exposed decaying forest floor materials.
Oh totally fair. But no solution is perfect, so we need to compare them against each other instead of studying each in a vacuum. Perfect should not be the enemy of the good, and etc. Sustainable forestry management is possible, and since we haven't done tonnes of applied research into it yet, I expect that the CO2 emissions reductions possible are still firmly in the 20% effort/80% return zone.
edit: I got a little nerd sniped XD I'd not looked into bridges much, so a bunch of this is new to me, but apparently FRP bridges are a thing! They seem primarily used for pedestrians, however. Covered wooden bridges have a surprisingly long service life (up to 100 years, with maintenance!), and we have extensive experience with wooden trestle bridges for rail traffic. It looks like there's some research into FRP as an alternative to steel for buried bridges (apparently, AKA "soil-steel composite bridge", or "steel culvert bridges) which can themselves be scaled up very impressively.
Super cool, and I appreciate the links! As you said, not trying to argue at all. I'll admit that I was taken aback by the sheer scale of concrete usage described in the article. It was hard to...
Super cool, and I appreciate the links! As you said, not trying to argue at all.
I'll admit that I was taken aback by the sheer scale of concrete usage described in the article. It was hard to imagine substituting an effective fraction of an industry that uses 4.5 billion tons of limestone annually for the Portland cement component. I can remember when "pave the Earth" was a big joke... 14 billion cubic meters of concrete poured per year feels unstoppable in the same way that fossil fuel use felt unstoppable until economies of scale worked for manufacturing the alternatives.
np! I always appreciate an excuse to dig into another field's business :3 and the bridges were particularly interesting; those nearly concrete-free vegetated buried arch bridges were amazing....
np! I always appreciate an excuse to dig into another field's business :3 and the bridges were particularly interesting; those nearly concrete-free vegetated buried arch bridges were amazing. Didn't even know that was possible!
And yeah, the scale of the problem is huge. Tbh I often lose hope when contemplating it. But these sorts of exercises have helped! It seems like we're like 15% away from sustainable, environmentally conscious solutions, for each deep dive I wind up doing, with basically no exceptions. The problem is enormous -- my old go to conversation starter (ender?) was to randomly point at an object in the room, and then to explain how its manufacturing is deeply intertwined with fossil fuel exploitation -- but it still feels tractable? At least, one bite at a time.
Everything you’re saying sounds reasonable to me, but I don’t run a construction business or factory! The alternatives must have some underlying cost and/or supply chain factor dampening their...
Everything you’re saying sounds reasonable to me, but I don’t run a construction business or factory!
There are robust, well tested alternatives! […] we did just fine…until concrete (as the article notes) became cost effective enough to replace it.
The alternatives must have some underlying cost and/or supply chain factor dampening their uptake—unless there’s a tremendous industry knowledge gap in the mix, which seems a watery proposition; or unless regulatory constraints make substitutes illegal, which is presumably only true for the most mountainous of structures, not sidewalk tiles or floors.
I believe you that many physical engineering challenges of concrete alternatives have been solved. I can accept the long-term view that society ought to pay the cost of more expensive, low-carbon material in a majority of circumstances to escape the externalities associated with concrete, which are higher in aggregate. (I could also accept the altruistic view that we should do so even if it’s a net loss on paper, for the purpose of saving an endangered fish or something else purely moral.) But I was convinced before I even opened the article. Policy hits a wall once a solution incurs short-term costs for the non-treehugging public constituency.
I would be interested to hear your perspective, as a person who knows more about this industry than me, on the particular substitute materials that are most likely on a fast-track to cost parity with concrete.
I’m also curious about holistic deployment. In the power sector, people rightly credit solar cell cost drops to much of the renewable boom, but industry analysts would have a lot to say about the buildout of financing infrastructure, establishing globally viable supply chains, and scaling up manufacturing capacity.
The article presents various ongoing initiatives to reduce emissions in the sector, but seems unconfident that they’ll become cost-competitive. It cites the concrete industry, who say that only carbon capture is an economically viable decarbonization accelerant.
So FYI I'm just some internet person 😅 my experience in this is that I'm spending a very large chunk of my life savings to build a workshop/loft that can support the next few decades of my life...
I would be interested to hear your perspective, as a person who knows more about this industry than me, on the particular substitute materials that are most likely on a fast-track to cost parity with concrete.
So FYI I'm just some internet person 😅 my experience in this is that I'm spending a very large chunk of my life savings to build a workshop/loft that can support the next few decades of my life (fleeing software dev and apartment rent; condolences if you're in a similar boat), and I couldn't stomach the idea of causing that much environmental damage without thoroughly researching the solution space in order to minimize it. The numbers seem to indicate that I'll be doing better than average, which is at least a small solace.
Anyhow!
The alternatives must have some underlying cost and/or supply chain factor dampening their uptake—unless there’s a tremendous industry knowledge gap in the mix, which seems a watery proposition; or unless regulatory constraints make substitutes illegal, which is presumably only true for the most mountainous of structures, not sidewalk tiles or floors.
I can mostly only speak to what I'm personally dealing with (permanent wood foundations and MSE retaining walls), but it's pretty much tremendous industry knowledge gaps that I'm confronting? At least with single family homes, people only build what they're used to, despite code and fifty years of practice indicating that different construction techniques work. Ultimately, since these projects will stand for decades, people who bear liability for them (e.g. builders, engineers, trades, etc.) are extremely conservative and slow to change. Absent a strong incentive (e.g. huge carbon taxes, building codes adjusted to forbid much embodied carbon, etc.) it doesn't seem likely that they'll try anything new.
If people were open to it, there's no reason why an overwhelming majority of single family homes (and many buildings up to about three stories + a basement) need use any concrete in their construction whatsoever. We have the technology and the knowhow, it's just isolated in places where concrete was always too expensive to deploy (backwoods and whatnot), so the institutional knowledge built up. They have several advantages, too, in that they cost less (wood is cheaper than concrete), can be prefabbed more efficiently (you can -- with great difficulty -- prefab concrete basement walls, but it sucks), and can be built rain or shine (it's a bad idea to pour concrete when it's cold or rainy, due to effects it has on curing). It's just inertia, really, and the perception of risk.
I expect that many places where concrete is perceived as absolutely necessary are probably similar? The problem is that it's a miracle material: easy to analyze, strong in compression and tension (with rebar), can be poured into any shape, immune to rot, and extremely robust against weathering. The alternatives need to be selected one at a time, for each application (often as a composite), instead of leaning on the default simplistic answer of using concrete. That knowledge requires experts in a given domain to spend a tonne of time analyzing requirements and coming up with solutions. For example, the only reason why permanent wood foundations exist is because of the 1970 oil crisis, which drove the development of concrete alternatives that required less energy in their production. I'm just working out of a CSA standard and a book that the Canadian Wood Council publishes to teach people about this stuff.
(apparently MSE retaining walls exist because an engineer/architect got bored on vacation playing with sand castles, however, so I guess sometimes this stuff happens spontaneously by accident)
I’m also curious about holistic deployment. In the power sector, people rightly credit solar cell cost drops to much of the renewable boom, but industry analysts would have a lot to say about the buildout of financing infrastructure, establishing globally viable supply chains, and scaling up manufacturing capacity.
Can't speak to that myself, unfortunately 😅 agreed, though! The engineering challenges involved are only one small part of the overall problem.
It cites the concrete industry, who say that only carbon capture is an economically viable decarbonization accelerant.
Yeah IMO a major reason for that is that they've already gotten all their easy wins out the door, so now we're stuck with e.g. using fly ash (from coal power plants) to reduce clinker, doing crazy stuff with geopolymers (and hoping that they work out as less carbon efficient), and etc. It'd be cool to see concrete production become greener! But, as a lay person, it seems like an extremely tough nut to crack.
Man, thats a pretty long article. I want to read this, its a topic Ive been interested in for a while, but I got about 1/3 of the way through and its really taking its time to get into things. Its...
Man, thats a pretty long article. I want to read this, its a topic Ive been interested in for a while, but I got about 1/3 of the way through and its really taking its time to get into things. Its like half infodump and half travel blog. Ill try again a bit later.
It certainly feels like three or four modern "deep insight" articles bolted together into one that follows the old monthly magazine feature format. For me, that was kind of nostalgic, and it does...
It certainly feels like three or four modern "deep insight" articles bolted together into one that follows the old monthly magazine feature format. For me, that was kind of nostalgic, and it does capture the human impact and complexity of the topic all in one story.
It's a matter of taste and attention span, but I mourn the loss of long, comprehensive news articles that provide adequate context and history for general readers. The few being written are paywalled, so I thought I'd share for anyone interested.
Yeah, it really is just a matter of taste. Personally I dont like interweaving the human interest aspect. Particularly when its something I already agree with going in, I dont like when articles...
Yeah, it really is just a matter of taste.
Personally I dont like interweaving the human interest aspect. Particularly when its something I already agree with going in, I dont like when articles feel like they are trying too hard to "sell" me on something. It calls into question in my mind how much I should be trusting the piece as a source of information. If someone is pushing really hard to lead you to a specific conclusion, they might be motivated to ignore or minimize certain details that arent convenient to what they are trying to argue.
Id be happy to read a piece of this same length if it was more dispassionate. For example, the article discusses the "hard problem" of calcium carbonate inherently needing to release carbon dioxide to become quicklime. There are some efforts being made to develop alternatives to using limestone. However I don't have any idea how economical that would be or if we can source alternative materials at the same rate we do limestone.
I would love to see a really thorough breakdown of something like that on a purely analytical level, where someone just investigates whether that seems like a good solution and presents their findings whether it gives them the answer they wanted or not. Like a scientific paper, but written in this more journalistic style.
Something like that I wouldnt mind the length at all, Id actually be thrilled about it.
Still glad you posted this though, its an interesting topic of discussion.
It's a Bloomberg Business article, and thus I find it remarkable that they included a detailed human interest narrative at all. I can understand wanting a more dispassionate tone, but the...
It's a Bloomberg Business article, and thus I find it remarkable that they included a detailed human interest narrative at all. I can understand wanting a more dispassionate tone, but the readership for that outlet might be shocked out of the familiar business-only zone and swayed by a direct illustration of the human impacts of failing to act on climate change.
Anyway, the article does discuss limestone alternatives or additives, like the pozzolanic ash used in Roman concrete.
Here's your vital equation for concrete and climate: CaCO3 + heat = CaO + CO2 or Calcite* + heat = Lime** + carbon dioxide *calcite is the principal mineral in most limestone **lime is the main...
Here's your vital equation for concrete and climate:
CaCO3 + heat = CaO + CO2
or
Calcite* + heat = Lime** + carbon dioxide
*calcite is the principal mineral in most limestone
**lime is the main ingredient in cement
Every kg of lime generates ~0.8 kg of carbon dioxide, before considering how temps of 2700°F are maintained. I'd read some studies of labs doing the process using far less energy using electrochemistry, though I don't recall the details, but it certainly wasn't at scale.
Blue Planet has an interesting approach, curious if that gains traction, but doesn't really help the concrete situation. Sure, it can substitute aggregate that hasn't captured atmospheric carbon, but doesn't change the above equation or method of making concrete.
I'm having a hard time buying these energy storage claims work out practically, but I don't imagine MIT attempts to commercialize ideas to be proven wrong.
It's a hard problem of climate change, if not one of the hardest, and doesn't get discussed too often. This article goes over a lot of the work going into it. Thanks for posting!
[Gifted article link, good for 7 days]
My modification to the title. This is an essential long read about concrete and it's most important ingredient, Portland cement.
Concrete is the key building material for modernity. Concrete's history, manufacture, carbon costs, economic impacts, engineering, distribution, and ever-growing uses have been significant contributors to climate-changing emissions.
Future developments in reengineering concrete's material composition, recycling, carbon capture during recycling, and other measures will be key to climate mitigation.
I'm absolutely agreed; this is super important! That said -- and I apologize for doing so -- I skimmed the sections which attempted to weave an emotional story about the damage that climate change wrecks upon the world's least fortunate, and focused directly on the science.
Here're my thoughts on the article!
There are robust, well tested alternatives! We've had permanent wood foundations (PWFs) since the 70s (example new construction a building science/marketing channel), and there are several approaches to avoiding putting in concrete floors (crawlspaces are an obvious one, which also have the benefit of making building utility repairs dramatically easier!). We even know how to build multi-storey buildings with only concrete in their foundations (example for up to six in Vancouver); one can imagine subbing in PWFs for those situations would be feasible, if potentially nerve wracking for the structural engineer of record.
Disagreed! I think that we've lacked the financial incentive to think outside the box in many fields, but that alternatives are clearly possible. In many cases, I'd imagine that fibreglass-reinforced plastics could take the place of concrete directly (e.g. wind turbines do this already), and in others, a thin concrete liner could provide chemical and wear resistance to an otherwise primarily plastic pipe (e.g. water transport). Manufacturing plants also needn't use concrete -- we did just fine with wood block floors for ages until concrete (as the article notes) became cost effective enough to replace it. Even dams can have their concrete usage dropped dramatically (for context, concrete is only necessary on the face of that retention structure; the rest of it is just plastic webbing and whatnot)
There are always going to be situations where concrete is absolutely necessary, but I would hazard that it's dramatically fewer than the places we use it today.
Ooh, yeah, the journalist should've caught that. They're comparing operational vs. embodied carbon, and that person is using a very motivated definition of "most" buildings. If folks are interested I can try to track down some old stats I was seeing, but afaik -- under modern building codes (for residential construction, at least), improvements to factors affecting operational efficiency (i.e. insulating, making improved windows, air sealing, modernizing HVAC, etc.) have effectively moved the target to embodied carbon, not away. I'd imagine that the executive who runs a company which produces the material responsible for ~36% ([1]) of a typical residential building's embodied carbon would have some motivation for getting ahead of criticism 😅
I, uh, no comment.
[1]: "Concrete is the leading contributor to emissions from the sample houses,
representing over 36 percent of all material emissions" Materials emissions benchmark report for part 9 homes in Vancouver, pg. 22
There are some serious limits on the substitutability of wood for concrete, though. You can build six-story timber frames, but not dense urban skyscrapers, roads, or massive dams, bridges, and subterranean infrastructure. I've seen those solid wood factory floors, and the modern cost would be astronomical given how few large-diameter hardwood trees are left. Fire-retardant technology has gotten better, there's research on silicated wood treatments that might resist wet conditions more effectively, but wood still won't make up more than a fraction of concrete applications.
I'm not saying we can't substitute a fair amount of concrete, though. For housing, adobe, rammed earth, modular panels, bamboo, and other solutions can still support fair density and lower environmental impact. Provided that they're chosen appropriately for local availability and conditions.
The article also mentions the risks from clear-cutting trees - damaging CO2 and methane emissions from exposed decaying forest floor materials.
Oh absolutely! To put my point more precisely: the most carbon efficient yard of concrete is the one we didn't use, so putting effort into reducing utilization is often a huge bang for the buck. In effectively every sense I do not see things as binaries, so I'm not proposing that the world can go "concrete-free" at the drop of the hat -- only that there's likely a lot of low hanging fruit by thinking about alternatives in end-uses, as opposed to pursuing diminishing returns surrounding CO2e reduction in concrete production.
I won't go point by point, since I don't think we're having like a debate or anything, but wood's good to 18 stories with mass timber (the structural system is mostly timber, but there's definitely concrete and steel in there playing supporting roles), and the floors mentioned don't use large diameter wood anyhow -- it's often 4x4's or 6x6's, and there's no compelling reason to keep 'em wood (they're still making them out of SYP, which is very much not old growth in 2026). Anything cellulostic with roughly the same material properties (i.e. endgrain is tough, can be sealed with oil) should behave similarly, too. Some industrial wood block flooring companies already do so with (seemingly) wood-plastic composites!
That's really cool! I think they're all out east, effectively, and I've never had a chance to see one in person. There're a few public spaces which have 'em and they've held up great, though!
Yeah I think that's where I would love to have more info? I threw a very cursory look into this, and turned up this dubious report. Taking their numbers with a grain of salt, it sounds like ~43% of cement usage is in roads/bridges, ~28% are residential, and 19% is "non-residential demand" (presumably, commercial/industrial, but the article frames it as "AI datacentres"). Even if we pretend that the 43% is untouchable (dubious IMO but perhaps there's a civil engineer around who could dig in further), that leaves another ~47% which could be meaningfully addressed by reducing concrete usage. For instance, it seems like AI datacentres are mostly one storey (just based on vibes, since searching it always turns up images like this one), which could easily be built without any concrete: gravity loads seem low enough to be handled with some of the plywood-on-grade flooring options, and if it's one storey, wood framing it (maybe with trusses to get decent enough clear spans for racks) seems very plausible.
🤦 apologies, I appear to have skipped this sentence before writing the above response. I suppose it still applies, but please consider it moreso a soft push instead of the hard counterpoint I had originally penned.
Oh totally fair. But no solution is perfect, so we need to compare them against each other instead of studying each in a vacuum. Perfect should not be the enemy of the good, and etc. Sustainable forestry management is possible, and since we haven't done tonnes of applied research into it yet, I expect that the CO2 emissions reductions possible are still firmly in the 20% effort/80% return zone.
edit: I got a little nerd sniped XD I'd not looked into bridges much, so a bunch of this is new to me, but apparently FRP bridges are a thing! They seem primarily used for pedestrians, however. Covered wooden bridges have a surprisingly long service life (up to 100 years, with maintenance!), and we have extensive experience with wooden trestle bridges for rail traffic. It looks like there's some research into FRP as an alternative to steel for buried bridges (apparently, AKA "soil-steel composite bridge", or "steel culvert bridges) which can themselves be scaled up very impressively.
Super cool, and I appreciate the links! As you said, not trying to argue at all.
I'll admit that I was taken aback by the sheer scale of concrete usage described in the article. It was hard to imagine substituting an effective fraction of an industry that uses 4.5 billion tons of limestone annually for the Portland cement component. I can remember when "pave the Earth" was a big joke... 14 billion cubic meters of concrete poured per year feels unstoppable in the same way that fossil fuel use felt unstoppable until economies of scale worked for manufacturing the alternatives.
np! I always appreciate an excuse to dig into another field's business :3 and the bridges were particularly interesting; those nearly concrete-free vegetated buried arch bridges were amazing. Didn't even know that was possible!
And yeah, the scale of the problem is huge. Tbh I often lose hope when contemplating it. But these sorts of exercises have helped! It seems like we're like 15% away from sustainable, environmentally conscious solutions, for each deep dive I wind up doing, with basically no exceptions. The problem is enormous -- my old go to conversation starter (ender?) was to randomly point at an object in the room, and then to explain how its manufacturing is deeply intertwined with fossil fuel exploitation -- but it still feels tractable? At least, one bite at a time.
Everything you’re saying sounds reasonable to me, but I don’t run a construction business or factory!
The alternatives must have some underlying cost and/or supply chain factor dampening their uptake—unless there’s a tremendous industry knowledge gap in the mix, which seems a watery proposition; or unless regulatory constraints make substitutes illegal, which is presumably only true for the most mountainous of structures, not sidewalk tiles or floors.
I believe you that many physical engineering challenges of concrete alternatives have been solved. I can accept the long-term view that society ought to pay the cost of more expensive, low-carbon material in a majority of circumstances to escape the externalities associated with concrete, which are higher in aggregate. (I could also accept the altruistic view that we should do so even if it’s a net loss on paper, for the purpose of saving an endangered fish or something else purely moral.) But I was convinced before I even opened the article. Policy hits a wall once a solution incurs short-term costs for the non-treehugging public constituency.
I would be interested to hear your perspective, as a person who knows more about this industry than me, on the particular substitute materials that are most likely on a fast-track to cost parity with concrete.
I’m also curious about holistic deployment. In the power sector, people rightly credit solar cell cost drops to much of the renewable boom, but industry analysts would have a lot to say about the buildout of financing infrastructure, establishing globally viable supply chains, and scaling up manufacturing capacity.
The article presents various ongoing initiatives to reduce emissions in the sector, but seems unconfident that they’ll become cost-competitive. It cites the concrete industry, who say that only carbon capture is an economically viable decarbonization accelerant.
So FYI I'm just some internet person 😅 my experience in this is that I'm spending a very large chunk of my life savings to build a workshop/loft that can support the next few decades of my life (fleeing software dev and apartment rent; condolences if you're in a similar boat), and I couldn't stomach the idea of causing that much environmental damage without thoroughly researching the solution space in order to minimize it. The numbers seem to indicate that I'll be doing better than average, which is at least a small solace.
Anyhow!
I can mostly only speak to what I'm personally dealing with (permanent wood foundations and MSE retaining walls), but it's pretty much tremendous industry knowledge gaps that I'm confronting? At least with single family homes, people only build what they're used to, despite code and fifty years of practice indicating that different construction techniques work. Ultimately, since these projects will stand for decades, people who bear liability for them (e.g. builders, engineers, trades, etc.) are extremely conservative and slow to change. Absent a strong incentive (e.g. huge carbon taxes, building codes adjusted to forbid much embodied carbon, etc.) it doesn't seem likely that they'll try anything new.
If people were open to it, there's no reason why an overwhelming majority of single family homes (and many buildings up to about three stories + a basement) need use any concrete in their construction whatsoever. We have the technology and the knowhow, it's just isolated in places where concrete was always too expensive to deploy (backwoods and whatnot), so the institutional knowledge built up. They have several advantages, too, in that they cost less (wood is cheaper than concrete), can be prefabbed more efficiently (you can -- with great difficulty -- prefab concrete basement walls, but it sucks), and can be built rain or shine (it's a bad idea to pour concrete when it's cold or rainy, due to effects it has on curing). It's just inertia, really, and the perception of risk.
I expect that many places where concrete is perceived as absolutely necessary are probably similar? The problem is that it's a miracle material: easy to analyze, strong in compression and tension (with rebar), can be poured into any shape, immune to rot, and extremely robust against weathering. The alternatives need to be selected one at a time, for each application (often as a composite), instead of leaning on the default simplistic answer of using concrete. That knowledge requires experts in a given domain to spend a tonne of time analyzing requirements and coming up with solutions. For example, the only reason why permanent wood foundations exist is because of the 1970 oil crisis, which drove the development of concrete alternatives that required less energy in their production. I'm just working out of a CSA standard and a book that the Canadian Wood Council publishes to teach people about this stuff.
(apparently MSE retaining walls exist because an engineer/architect got bored on vacation playing with sand castles, however, so I guess sometimes this stuff happens spontaneously by accident)
Can't speak to that myself, unfortunately 😅 agreed, though! The engineering challenges involved are only one small part of the overall problem.
Yeah IMO a major reason for that is that they've already gotten all their easy wins out the door, so now we're stuck with e.g. using fly ash (from coal power plants) to reduce clinker, doing crazy stuff with geopolymers (and hoping that they work out as less carbon efficient), and etc. It'd be cool to see concrete production become greener! But, as a lay person, it seems like an extremely tough nut to crack.
Man, thats a pretty long article. I want to read this, its a topic Ive been interested in for a while, but I got about 1/3 of the way through and its really taking its time to get into things. Its like half infodump and half travel blog. Ill try again a bit later.
It certainly feels like three or four modern "deep insight" articles bolted together into one that follows the old monthly magazine feature format. For me, that was kind of nostalgic, and it does capture the human impact and complexity of the topic all in one story.
It's a matter of taste and attention span, but I mourn the loss of long, comprehensive news articles that provide adequate context and history for general readers. The few being written are paywalled, so I thought I'd share for anyone interested.
Yeah, it really is just a matter of taste.
Personally I dont like interweaving the human interest aspect. Particularly when its something I already agree with going in, I dont like when articles feel like they are trying too hard to "sell" me on something. It calls into question in my mind how much I should be trusting the piece as a source of information. If someone is pushing really hard to lead you to a specific conclusion, they might be motivated to ignore or minimize certain details that arent convenient to what they are trying to argue.
Id be happy to read a piece of this same length if it was more dispassionate. For example, the article discusses the "hard problem" of calcium carbonate inherently needing to release carbon dioxide to become quicklime. There are some efforts being made to develop alternatives to using limestone. However I don't have any idea how economical that would be or if we can source alternative materials at the same rate we do limestone.
I would love to see a really thorough breakdown of something like that on a purely analytical level, where someone just investigates whether that seems like a good solution and presents their findings whether it gives them the answer they wanted or not. Like a scientific paper, but written in this more journalistic style.
Something like that I wouldnt mind the length at all, Id actually be thrilled about it.
Still glad you posted this though, its an interesting topic of discussion.
It's a Bloomberg Business article, and thus I find it remarkable that they included a detailed human interest narrative at all. I can understand wanting a more dispassionate tone, but the readership for that outlet might be shocked out of the familiar business-only zone and swayed by a direct illustration of the human impacts of failing to act on climate change.
Anyway, the article does discuss limestone alternatives or additives, like the pozzolanic ash used in Roman concrete.
Here's your vital equation for concrete and climate:
CaCO3 + heat = CaO + CO2
or
Calcite* + heat = Lime** + carbon dioxide
*calcite is the principal mineral in most limestone
**lime is the main ingredient in cement
Every kg of lime generates ~0.8 kg of carbon dioxide, before considering how temps of 2700°F are maintained. I'd read some studies of labs doing the process using far less energy using electrochemistry, though I don't recall the details, but it certainly wasn't at scale.
Blue Planet has an interesting approach, curious if that gains traction, but doesn't really help the concrete situation. Sure, it can substitute aggregate that hasn't captured atmospheric carbon, but doesn't change the above equation or method of making concrete.
I'm having a hard time buying these energy storage claims work out practically, but I don't imagine MIT attempts to commercialize ideas to be proven wrong.
It's a hard problem of climate change, if not one of the hardest, and doesn't get discussed too often. This article goes over a lot of the work going into it. Thanks for posting!
Side comment: that's an awful lot of tags! Are you autogenerating them somehow?
Nope, purely handcrafted tags. I suppose I'd post more often if I wasn't so obsessive about keyword labeling.