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Cement is the source of 8% of the world's CO2 emissions (2018) (bbc.com)
236 points by fn1 32 days ago | hide | past | favorite | 149 comments

The largest issue with concrete is that we misuse it. As a building material it has great thermal mass ( aiding temperature stability ) and longevity. But all too often buildings are poorly designed for renovation, and hence end up being torn down after a couple of decades. A small fraction of the useful lifetime of the structure. Any building using concrete for a structure should be aiming to last at least 100 years.

For those who didn't read the article: the chemistry of Portland cement works against it. Production requires heating the calcium carbonate to a high temperature to extract carbon dioxide from it. Which obviously produces large amounts of CO2 proportional to concrete production. However, concrete also absorbs carbon dioxide from the air over its lifetime. So the measured emissions aren't the entire story.

Perhaps in future we will consider this an excellent source of carbon dioxide for the production of various hydrocarbons. I've heard of several efforts to create octane using carbon dioxide from the air, but you need a large amount of energy to extract a useful amount of CO2. Well this would be a good source of high concentration CO2. Perhaps not for octane ( we should really be moving away from combustion engines ) but perhaps plastics and other products that are currently derived from crude oil.

> Any building using concrete for a structure should be aiming to last at least 100 years.

I don't know which country you have in mind but in Europe the construction industry by law is obligated to design concrete structures for residential buildings that ensures a useful life of at least 50 years, and by definition that means that the building structure shall not require maintenance for at least 50 years.

Moreover, concrete as a widespread structural material is relatively new, and city centers are still packed with contrete buildings that were built when the technology started popping up.

In fact, in general a building with concrete structure is only demolished when it's not possible to retrofit or renovate it effectively, due to unrelated reasons such as increasing occupation density that would not be cost-effective by reinforcing the concrete structure.

My point is that concrete structures are not demolished with enough frequency to be of any concern. The main reason is that concrete structures are simply too expensive to be demolished, moreso in urban centers. Thus your concern simply isn't relevant in the real world because economics already impose the same restrictions that are expressed in your environmental concerns.

Maybe in Europe, but in the United States if you want to tear down a building and build another one, there is about a 99% chance you can do that and get the paperwork for it without too many hurdles other than NIMBYs.

That's an entirely unrelated issue, and fits the case of urban renewal projects whose preexisting building is not able to accommodate new functional requirements, at least in a cost-effective way.

The only factor that the use of concrete plays in this scenario is that concrete structures are expensive and time-consuming to demolish. If the investment makes financial sense then the choice of building material doesn't make any difference.

In Finland there is effort to capture carbon from industrial emissions and eventually from the air. Pulp mills are very promising.

Turning the cons of concrete into pros (carbon-cured concrete) https://www.vttresearch.com/en/news-and-ideas/turning-cons-c...

>carbon-cured concrete: in carbon curing, concrete is cured with gaseous carbon dioxide, from the plastic phase forward. The curing of concrete with pressurized carbon dioxide generates not only the ordinary reaction products of cement but also carbonate-based reaction products. Consequently, the process binds carbon dioxide, and it is even possible to make the final product carbon negative if ordinary cement is replaced with alternative binders with a low carbon footprint.

The Carbon Reuse Economy: Transforming CO2 from a pollutant into a resource https://cris.vtt.fi/en/publications/the-carbon-reuse-economy...

Do we want 100 year old buildings? I don't think we can predict the needs of building even 20 years into the future. City layout could change drastically. Monumental buildings should last a long time, but not every structure.

The alternative is to build from wood whenever possible, and capture extra cabon in building material. This increases market need for wood and therefore forestation.

> Do we want 100 year old buildings? I don't think we can predict the needs of building even 20 years into the future.

My parents live in a house that was originally built in the 1890s. It first had a fire place and wood stove for eating/cooking (surmised via chimneys), then it had gas lighting (some pipe are still in the walls), then it knob-and-tube lighting, then modern electrical lighting and cooking.

Walls were replaced, insulation added, etc. Lots of internal changes.

But the foundations and external brick is original (AFAICT).

Buildings are just boxes for people which keep the cold/heat/moisture at a comfortable level. As long as the "bones" of the buildings are good seismically, the "skin" has proper environmental control, then you can shuffle the inside around without too many issues.

Design/build things with minimal internal load-bearing walls and things can be shuffled fairly easily. Perhaps also use trusses instead of rafters as well for easier running of piping/wire.

> Buildings are just boxes for people which keep the cold/heat/moisture at a comfortable level.

So true. With the knowledge we have now about building materials you could create a very versatile, rigid, energy efficient base structure that lasts > 100 years, and adapt/update the internals to the current needs. You could even change the room layout completely.

I live in Europe and I can't understand why houses in the US are built with wood and drywall. It surely must be cheaper to use bricks/concrete and then renovate it fully every 20 years, or am I wrong here?

You are not wrong. However, houses could still be built from wood like the 500 year old houses and churches made with actual timbers. Timber framed houses would use a lot less wood in the long run due to less waste and greater longevity (especially when coupled with bricks and concrete).

Milling large trees down to 2x4s and coupling it to drywall to build homes that don't last is a travesty.

What are you counting as a house that hasn’t lasted? 50 years? 100? The house I am in was built in the 1940’s by the state as an employment and housing scheme for returned servicemen post WW2. It’s wood framed and has a fair few years of life left if cared for.

The bulk of NZ houses are wooden, and have been for its entire history. They are also cold and are often damp, though these problems can be solved with decent building practices.

Concrete and brick are not that desirable in an earthquake prone country.

And yes, milling big old trees is bad. They are now made of treated pine, which comes with its own environmental concerns.

I think that Europeans just are biased against wood frame houses. I've heard this argument over and but a wood frame house can easily last 100+ years with maintenance and owners who care about what happens to it.

OP here. I guess you are right about the bias. I've learned a lot from this thread, thank you!

The funny thing is that Europe some really old wooden buildings. There is a 1200 year old one in Essex.


There's a lot of great youtubers out there who document their work in construction. It seems like a subset of contractors/architects/builders are interested in doing "experimental" things and improving the world's understanding of how to build buildings.

This one is about energy efficiency: https://www.youtube.com/watch?v=mBOvflXoWlw

I'm really interested in finding more videos like this because his videos go past "Home Depot said this is energy efficient", he instead tests these concepts and apparently works with different colleges that research these ideas.

Properly maintained wood houses are good for 100 years. My house is 70 years old. It required insulation and electrical upgrades, mostly diy, but is otherwise fine. Also, the wood is a carbon sink, vs masonry being a carbon source.

> I live in Europe and I can't understand why houses in the US are built with wood and drywall. It surely must be cheaper to use bricks/concrete and then renovate it fully every 20 years, or am I wrong here?

I would think that renovations are much easier to do, regardless of the time interval between them, with wood and drywall. Drywall can be torn apart with by someone with just their hands; wood may need some cutting, but once in shorter pieces, can often just be yanked. Even a large house can probably be gutted/internally-exposed in a day or two.

With any kind of masonry you have to swing a sledge hammer with a lot of force or bring in jack hammers. Once set, concrete will resist a lot of force against it, which is why it's generally used for slabs and foundations.

It also depends on what you mean by renovate: often changes are in internal layout, so if one uses good design techniques for the shell:

* https://www.buildingscience.com/documents/insights/bsi-001-t...

And floor trusses to reduce/eliminate internal load-bearing walls:

* https://www.youtube.com/watch?v=ysT3zXkFGB8

It give completely flexibility on what can be done inside the box.

Wood is also fairly cheap and plentiful in North America.

As for drywall: what are the alternatives for internal walls? Lath and plaster?

* https://en.wikipedia.org/wiki/Lath_and_plaster

Some growth in popularity for wood in Europe; some Swiss examples:

* https://www.youtube.com/watch?v=RlplalGNfFM

* https://www.youtube.com/watch?v=4j_UjIshzMc

Why would you remove concrete and masonry every 20 years? I don't have much experience with wooden houses, so I don't know if it's the case there.

But in brick houses renovation often means fixing what's broken and adding modern technologies such as insulation. Moving or adding walls can easily become quite a large scale project.

I think he means changing the room layout. In Europe, usually all the walls are 'set in stone'. Using a combination of masonry/concrete for the outer shell and timber/drywall for the internal walls would eliminate this problem though.

Wood is cheaper in North America than it is over there. Also it has some advantages, like being easy and cheap to work with, safer in areas with seismic activity, and it’s renewable.

Wood structures have no issues lasting 100+ years as long as they’re protected from water and termite damage.

On the east coast I’ve lived in plenty of wood houses that were built in the mid 1900s and just renovated every few decades. My last rental was even originally built in 1910. Well built wood frames can last for a long time.

Renovate every 20 years? There are plenty of wood houses that are hundreds of years old and have had minimal renovation to the wood frame.

Yeah if you can keep it dry (take care of roof and siding) and keep termites away they can last a long time. Especially older homes that have sturdier frames (when a 2x4 was really 2x4) built with old growth wood which tends to have tighter grain and therefore more strength.

This is true. Longevity of wood homes varies a lot by location.

California? They last a long time. Deep South? I assume they don’t last as long. Canada? They last a long time.

> Do we want 100 year old buildings?

At least a fifth of the UKs housing stock is over a century old, so the answer to that question is yes, if they're built properly...

I haven’t been impressed by any of the old UK houses I’ve been in, from rowhouses in London to detached houses in a midlands to mansion in Cotswald.

The insulation, pipes, and wiring all are quite inferior to modern standards.

London especially suffers from lots of shoddy conversions.

However, buildings built today to today's modern standards (with a little foresight) could easily be fine 100 years in the future. I'm not talking about fragile glass showpieces, but simple properly insulated homes built from durable materials.

We call that “character”.

My biggest issue with old homes is the layouts tend to be weird for today’s uses. Where I live many of the homes have a lot of small rooms and and narrow doorways instead of larger ones, for instance.

This of course goes back to conserving heat. But it makes house hunting difficult when trying to find a house with a layout you like.

Do we want 100 year old buildings?

The house where I grew up was made before Portland came to our zone, so it was made of lime mortar and rocks, some of them as big as a mellon, I found out when I tried to drill the walls to put a basketball basket.

It was demolished in the eighties, but not because it was in bad shape. I met the bulldozer operator years later and he recalled how he had a hard time with it.

I'm sure it would have been fine today, when it would be 100 y.o. or close. And I'm sure there's no other place where I'd rather live. It was cool in the summer, easy to warm in the winter, no mold, little noise from the outside.

> Do we want 100 year old buildings?

Obviously, we do.

To put it in terms that may be easier to understand, we do not want to demolish a building when it serves all functional requirements.

Double so if they have urban and cultural value.

I suggest you visit places such as Amsterdam, where most of the city center was built in the 17th century and it's glorious.

>Do we want 100 year old buildings?

I don't want a new house. Why? Because I refuse to live in a house with no natural ventilation. Most modern houses need air condition or at least ventilation systems, because they need to be so energy efficient, that there is no other way to get fresh air in. The fact that a house needs to be pressure tested seems insane.

Sure you can leave the windows open, but that defeats the purpose. Modern home needs to be ventilated three times a day, that means opening all the windows in the morning, when you get home in the afternoon and before going to bed. How many people will remember to do that?

The air in a modern home is often so dry that my nose start running the minute I enter. I don't want to live in that sort of climate.

Depending on the country, I think people should aim for home built from the late 1940 to mid 1970. Most likely additional isolation and new windows have been added over the years, making them reasonably energy efficient.

> The fact that a house needs to be pressure tested seems insane.

What's the alternative, building intentionally leaky houses? Better to be able to control the leaks to your benefit, aka active ventilation.

> Sure you can leave the windows open, but that defeats the purpose.

Actually the purpose of wind-ows is to let the wind in - no pun, that's the actually etymology of the word, (also in Spanish: ventana originally meant "for venting").

Even in an old air-leaky house if you don't open your windows, the ventilation is happening through your walls, using them as an air filter which they were not designed to be, and in the process pulling moisture through them, which can cause all kid of bad stuff to grow in them. You shouldn't rely on such passive depressurization for ventilation, as it depends totally on pressure differences between indoors and outdoors.

> Most modern houses need air condition or at least ventilation systems, because they need to be so energy efficient, that there is no other way to get fresh air in.

There absolutely are ways to get fresh air in and dirty air out, including the following:

- Exhaust ventilation systems (i.e. whole home extractor fans)

- Balanced ventilation systems

- Energy/Heat Recovery Ventilation systems.

The poorly ventilated houses you are referring to were built between the 80s and 90s - yes they have ventilation issues. I know this because I own such a house and have fixed the ventilation issues with solutions from the list above.

Today in most areas, some form of mechanical ventilation is required by code on new construction, and has been for 15 or so years.

> The air in a modern home is often so dry that my nose start running the minute I enter. I don't want to live in that sort of climate.

In cold climates, the ability to safely humidify a house depends mainly on having good enough insulation and air sealing that the indoor humidity doesn’t condense on cold surfaces and rot the building. This is especially relevant near windows.

So if you want decent indoor humidity when it’s genuinely cold out, you want double- or triple-paned windows with insulated edges, proper air sealing near the windows, and possibly even an energy recovery ventilator.

(Or you can live in an old house, spend stupid amounts of money to heat it all the way to 63 degrees for a few hours a day, be cold and dry, and wonder what the heck anyone was thinking when they designed their single-pipe steam heating system.)

P.S. It is supposedly possible to properly design a single pipe steam heating system that achieves a comfortable temperature in more than one room. If so, I have never seen such a thing.

> It is supposedly possibly to properly design a single pipe steam heating system that achieves a comfortable temperature in more than one room.

If you are interested in learning more about this "possibility", particularly if you have a steam system that you hate, you'd probably enjoy Dan Holohan's books. His basic thesis is that when designed and installed, they worked well, but the knowledge necessary to keep them functional has been lost over the years. Here's a New Yorker profile of him: https://www.newyorker.com/magazine/2016/01/04/steamed-the-jo...

> Sure you can leave the windows open, but that defeats the purpose. Modern home needs to be ventilated three times a day, that means opening all the windows in the morning, when you get home in the afternoon and before going to bed. How many people will remember to do that?

I don't really understand your objection. in a leaky old style building without an effective moisture/thermal barrier, you don't get to choose whether ventilation is happening; it always is. with modern sealing, you can open the windows if you prefer fresh air, or you can enjoy much more efficient AC/heat if you don't. why couldn't you live in a modern home and just leave the windows open? it's easy to get a good draft going in any multifloor building with windows.

> open the windows if you prefer fresh air, or you can enjoy much more efficient AC/heat

How can something powered by electricity/natural gas/etc be more efficient than simply opening the windows and letting Mother Nature do the work?

poor wording. I mean more efficient than ac/heat in a leaky house.

Most new homes today include heat recovery ventilators that continuously cycle the air from outside.

I’m looking to buy a place in Berlin, and from the search results it feels like half of the apartment buildings are from 1880-1910. I’m renting in a very old (not sure exactly how old) building, and it is… fine. It has been renovated, it is warm, it has double glazing. The only thing wrong with it is the walls are too thin for modern sound systems, but even that is less of a problem here than (for example) my university accommodation in Aberystwyth, because Germans care a lot about quiet time. The only reason I’m skipping anything pre-1950 is that I want to own it for at least 30 years.

I think we do, if we design them properly in the first place. For example, in 11 years the empire state building will be 100 years old, and its still an very useful and beautiful building. I think as long as you design a building to use something like conduits, you can update the wiring, plumbing, hvac, elevators, etc over time and it can continue to be useful for centuries.

The house I grew up in in rural UK was built in about 1910. My university accommodation was built in the 1880s. The first place I lived in when I moved to London was Victoria, as is where I'm living now. The newest place I've lived for longer than a few months was a flat-share in a 1960s block. For huge amounts of people, >100 year old housing is the norm.

My house is at least 200 year old and have been inhabited by 4-5 families. Although I must admit that it is thermally very bad, its perfectly livable.

Now the thing is that I like old houses.

So, just pay a nice marketing team to make sure people love old houses (after all, we have marketing team that can sell poison such as cigarettes or carbon dioxide).

Or, as you said, just build with something easier to handle such as wood (provided you recycle it, else it'll go back to biomass, releasing its CO2 again)

I don't think we want 100yr old buildings (except for history like a famous temple etc.). Certainly in my country old buildings are not designed in any environmentally conscious way. They aren't energy saving. They aren't in any way designed to be naturally cooler in the summer or hotter in the winter. They aren't designed for the changing needs of society which went from walking and horses 100 years ago whatever it is today. Why would I think a building made today is going to be a good building for the needs of people 100yrs from now?

Many old buildings where designed to be cool in the summer and warm in the winter. Often those features have been removed as historically airflow kept things cool where today you want to maintain AC.

It’s something of a design failure of modern buildings where walking outside when it’s 80f is pleasant but inside you need AC at those temperatures.

Very interesting, didn't expect it to be that high. Another thing I came across recently : The fashion industry is responsible for 10 % of annual global carbon emissions. Source : https://www.worldbank.org/en/news/feature/2019/09/23/costo-m...

Statistics on how much CO2 something emits can vary wildly. For instance, meat consumption has high CO2 emissions when you include the CO2 emitted by transporting grain to feed animals. But most typical studies would include that under emissions due to transportation. Hence why you can have some studies claiming meat accounts for a double-digit percentage of emissions while others claim that all agriculture contributes to ~3% of emissions.

The citation for this claim doesn't seem very robust. It links to the Ellen MacArthur foundation website, but just to the front page. After some of my own Googling it looks like it's coming from this publication [1]. This study drew up some estimates on the amount of textiles produced and discarded as well as a simple conversion of 4.7 Kg of CO2 for every Kg of textiles produced. The source for this ratio of CO2 to kilogram of textiles simply says "McKinsey Analysis"/

1. https://www.ellenmacarthurfoundation.org/assets/downloads/pu...

I’ve always wondered how much standardisation there is in reporting these types of numbers, particularly with regard to countries, albeit not enough to actually look in to it.

Say Australia digs up some coal, ships it to China, it’s used to power factories and smelters to produce goods, then those goods are shipped to and used by Americans. Is there consensus on who the pollution from burning coal gets tied to? Or does it vary per report and article?

It goes to China, because it is the one that can change it. But that's when you're looking at the output of countries. What you could also do is look at the output of individual persons, and then you could more easily attribute the CO2 to the American.

Sustainable energy without the hot air does this, it's a great book though I've heard it's somewhat outdated now.

The analytic approach is great, but the numbers are very out of date.

It depends on what type of accounting is being used. If it’s a production-based accounting then they’ll be attributed to China. But if it’s a bottom-up, consumption-based accounting then they’ll be attributed to the consumer in the United States.

It’s great that both approaches exist, because they surface different conclusions. If you want to see where the actual emissions are being emitted, or what “industry” they’re from, then the production-based accounting will give you that. If you instead want to see what different consumer-level behaviors are responsible for most emissions then you’ll need a consumption-based accounting.

That duality is what makes it hard for people to grok carbon accounting estimates sometimes.

It gets tied to China, for better or worse.

These different sources are classified as Scope 1 2 and 3:

- Scope 1 emissions are direct emissions from owned or controlled sources. - Scope 2 emissions are indirect emissions from the generation of purchased energy. - Scope 3 emissions are all indirect emissions (not included in scope 2) that occur in the value chain of the reporting company, including both upstream and downstream emissions.

So grain purchased and shipped to the animals is measured under Scope 3. Powering the lights and machinery on the farm is Scope 2.

It's tricky and inexact to do GHG accounting, but the same methodology and emissions factors are used everywhere so at least it's comparable between companies and products.

About meat specifically -- one has to be careful when counting all greenhouse gases versus just CO2, and pure quantity of gas vs. effect on global warming.

Cattle produces a lot of methane, which has a very powerful greenhouse effect, a lot more powerful than CO2. So while it does not contribute to CO2 emissions that much, it contributes to the greenhouse effect proportionally a lot more.

CO2e is standard when talking about GHG which takes this into account.

The methane has lower cumulative impact and is a closed loop where it gets recycled over time. [1]

[1] https://onezero.medium.com/cow-farts-are-not-the-problem-f57...

Oh yeah, I remeber also driving once next to a large farm with cows, it's crazy how much of the gas they produce.

got some downvotes, but I guess those people never experienced, you can close air circulation in your car and still smell it, it's that bad.

Also an interesting study compared what people bought who didn't buy meat, as vegetarian diet tends to be cheaper too. This brought the carbon difference to within 2%. I can't find it but think it was from Swedish researchers.

That was my biggest take away from the Biosphere documentary, as it was the concrete used in it's construction that eventually led to the abundance of CO2 and lack of O2 in that closed system.

We'll clearly have to use something else for building moon bases.

I’m not sure you’re right there.

Co2 is released in the production of cement (in cement factories). Once it’s used in the buildings it actually sucks back some of that co2 back during the first years.

In biosphere cement was actually a carbon sink, but it threw the system off balance, because it caused bacteria to eat more oxygen than expected.


Sorry for the tangential drift but it's ubiquitous now. I guess those boring grammar pedants should finally give up. The totally meaningless and incorrect apostrophe in it's (unless it indicates an abbreviation) has gone viral. You can even find it in headlines in newspapers. Odd really that many of us go to the trouble of adding a pointless character intent as we are on writing correct English. I think we should keep on trying though.

I suspect a lot of the rise is fueled by autocorrupt on smartphones. It changes every damn time on iPhone, and it takes effort to get it with no apostrophe.

The English language changes over time.

Why would a moonbase need to be a closed system? What would stop it scrubbing the CO2 and venting it in to space?

Does the vacuum of space generally require a closed system? And venting the CO2 is bad for the same reason that the heat death of the universe is bad; at some point you have converted all of the usable stuff into useless stuff and have vented it somewhere that you will be unlikely or impossible to be able to recover it.

If we do that, we will have to resupply the O2 in some way other than converting CO2 back to oxygen. Either shipping new gas to the moonbase, or having the moonbase convert organic material on the moon to O2 (which sounds a lot more expensive and difficult than having plants scrub CO2 into O2 for us).

This is also not to mention the other valuable things were venting with the CO2 (heat for one; I assume keeping a moonbase at a livable temperature would be a struggle). Your scrubber also has to be able to replenish the gas while it's venting, or you risk having rapidly fluctuating pressures in the moonbase. Which is going to be uncomfortable for living things, and will require whatever the moonbase is made out of to be able to handle those changes in pressure (again, I imagine having pressure that fluctuates like a bounce house with a group of sugared up children in it is less than ideal). It's not hard to imagine a non-rigid structure like the base from The Martian bouncing off the surface of the moon when it rapidly constricts from venting CO2 and then rapidly inflates as the O2 replenisher kicks on. It would become a massive bouncy ball in 0G.

Eventually, you could convert all O2 to CO2 and be left with nothing?

I don’t think it’s clear at all that concrete wouldn’t work for a moon base. I can definitely at least imagine that there might be some CO2-scrubbing technology that might be practical on the scale of a moon base that wouldn’t be if scaled up to the entire planet Earth.

The good news is that there's very little calcium carbonate on the moon, so you'll have to build it out of something else. Probably thermally fused silicates.

So the biggest polluters are food, clothing and shelter - I'm seeing a pattern here...

Yes, but the question is, how much of these emissions come from the basics, and how much from extravagance?

The question is how do you define extravagance? Ask someone in a middle class suburb of the US and you will get a different answer than the most of the rest of the world.

The biggest extravagance is space. Having space (I.e. detached houses) has a knock on effect of increased emissions of everything. Increased energy usage to transport mass increased distance.

Clothes industry has long stopped being about clothing and moved to stroking egos instead (infinite stream of money in that). It is even reflected in the name change ("clothing" -> "fashion").

Transportation and heating are in there as well

Doesn't matter. The rags companies get clothing and Africa imports tons of clothing for free. The clothes aren't all just made and discarded, they often have a second life.

this is a much more depressing number. steel and cement are necessary to the development of all nations, designer clothes are not.

This seems unlikely. Clothing is about a $1.3 trillion market, against a world GDP of about $80 trillion. I doubt that an industry that's 1.6% of GDP is contributing 10% to carbon emissions.

Also, as pointed out below, the "fashion industry" includes all clothing. Beyond food and water, I'm not sure what would be more necessary than clothing.

The overwhelming majority of clothing produced is totally unnecessary. The fast fashion industry produces an insane amount of clothing, way beyond what is necessary for utilitarian purposes. I don't doubt that it causes that much CO2 emission, especially if you factor in the shipping cost from the places that manufacture it.

I believe this is generally true of any utility. We can all live of soylent or something instead of moving around foods that spoil easily for example. We could all also live in large concrete block where everyone has a small room and houses don't exist. All of that would be hugely more efficient but I doubt you or many other people would like that.

A bit of an excluded middle - soylent or what we have now, a massivly wasteful and inneficient food system. I, and many others, would argue that localization and diversification of the food system is the missing middle here.

Fashion refers to all clothing. "fast fashion" (cheap disposable clothing) probably produces a lot more emissions than designer clothing.

Clothes are discarded but can be turned into rags or donations. Don't feel bad, I bought some very nice stuff for cheap and I didn't hurt the environment more. I'll just drive these wonderful finds I got for $5 30 miles home in my Hummer.

Garments that are high quality are designed to last and be worn for a long time. High end selvedge jeans might run a couple hundred bucks, but they will last a decade.

I suspect cheap, disposable clothing is driving much more emissions.

> High end selvedge jeans might run a couple hundred bucks, but they will last a decade.

Is there any data supporting this? Because while I think this is our intuition, i.e. "it's expensive therefore it's better quality," I wonder if there's any way we could verify this other than anecdotal evidence.

You see the British aristocracy wearing 30+ year old shoes that look as good or better than they did when they were new.

I think it is common sense that emissions are far lower for extreme-luxury clothing that can be repaired and is timeless verses disposable clothing that last one or two years.

We're not talking extreme-luxury clothing here though. We're talking Ralph Lauren vs H&M, or something similar. What the British aristocracy wears is probably hand-made stuff by world-class artisans. What Ralph Lauren makes is mass produced in either Europe or China, so it's a much closer comparison to H&M (not to mention still within the reach of an average person in a rich country)

I'm not sure if jeans that are torn/blown out can be seamlessly mended the way shoes can be.

Low end selvedge denim lasts longer than a decade and even low quality denim lasts. You don't wear stuff out of fashion though, it would be like wearing the best of the 90s. You're also assuming that the clothes get worn. The cheaper stuff may just be worn as much as the high quality stuff or that they continue to be used.

The article doesn't mention one alternative: CLT (cross laminated timber) as a building material for houses and flats. See https://www.bbc.com/future/article/20190717-climate-change-w... for example.

Using CLT (and passive house principles) can reduce the total CO2 emmissions of a house by 90% in its total life span. The wood in CLT stores carbon and the passive house principles reduces energy needs.

Yes. And better than that using this at scale is going to require massively scaling up wood production (i.e. forestry). This too will help with capturing a lot of co2 in the soil. A lot of countries would end up restoring farm land to production forests and probably end up using sustainable practices for this.

For those unfamiliar with CLT, this is a high tech building material suitable for making e.g. sky scrapers or other types of buildings. It's much lighter and stronger than concrete. Because it is lighter, you save a lot of fuel transporting it. It's fire resistant and rot resistant because it is chemically treated. It's also much easier to work with as you can drill, glue, saw, etc. it. Additionally, you can do this off site meaning actual onsite construction activities are a lot more straight forward, less noisy, and much less wasteful. Think Ikea for buildings.

To sketch you a picture of how awesome this stuff is, the Japanese are planning to build a 1100 feet skyscraper made of wood, steel, and clt in Tokyo, which is of course a city that regularly sees earthquakes and tropical storms. https://www.archdaily.com/889142/japan-plans-for-supertall-w....

The biggest challenge is going to be simply scaling the production of this material and transitioning the construction industry to mostly using this instead of concrete. Right now it's kind of a novelty / niche thing and it is going to take a while to reach efficiencies and economies of scale we have with concrete today. It's not exactly cheap (yet) but it could become cheaper long term; especially if you consider all the benefits (technical and environmental).

What are the long term health effects of the chemicals used in the production of CLT, on the residents of the houses?

According to this article: https://www.bbc.com/future/article/20190717-climate-change-w..., it's less than 1% vs 10% in things like plywood and does not use dangerous chemicals:

" Other engineered woods such as plywood and MDF are around 10% adhesive (glue), often urea-formaldehyde, which can produce hazardous chemicals during recycling or incineration. CLT, however, is below 1% adhesive, and typically uses a bio-based polyurethane. The planks are bonded together under heat and pressure to fuse that small amount of adhesive using the moisture of the wood. To look at, smell and touch, it’s as pure wood as a child’s tree house – knots and all. "

In any case, there are already quite a few buildings that use this so, I'd say this is a non-issue.

Good question.

There is also CLT without glue. Check https://www.youtube.com/watch?v=4j_UjIshzMc where Matt Risinger is visiting a Swiss factory where they use wooden (berch?) nails and dowel pins in stead of glue. And by using more layers they also need no insulation. Gives R=24...

Some adhesives use formaldehyde, but you can also get formaldehyde free adhesives. It's no different than plywood or OSB which is greatly used in the construction of most wooden stick framed houses where that's common (i.e. North America).

It's the same chemicals used in the production of plywood (glue), only there's a lot less of it. It basically is plywood, just with fewer and thicker layers so a lot less glue is needed.

At least per 2019 when it was opened Mjøstårnet[1] is the world's tallest timber building. It's only 85.4m (218ft) though[2].

There's also a report[3] about a glulam burn test, something I was quite curious about.

[1]: https://www.moelven.com/mjostarnet/

[2]: https://en.wikipedia.org/wiki/Mj%C3%B8st%C3%A5rnet

[3]: https://www.moelven.com/mjostarnet/glulam-can-withstand-a-bu...

The wikipedia page you link to says it has a concrete core.

I think you misread? The concrete core is in reference to a building in Austria.

"As the main vertical/lateral structural elements and the floor spanning systems of Mjøstårnet are constructed from timber, the building is considered an all-timber structure."

I misread. I appreciate the correction.

While CLT has been certified for 60 years, I don't know how the adhesives they are using are certified for that long. The working life of common industrial adhesives is remarkably short [1]. The key is not just moisture control, but also temperature regulation.

With rigorous humidity and temperature regulation, some adhesives have an as-yet undetermined lifespan. I'm still looking for transportable passive designs without active mechanical assistance that keep humidity at or below 40% and temperature variation to within ±10° C in temperate zones.

[1] https://www.bhhomeinspections.com/building-materials-life-ex...

[2] http://www.woodcentral.com/woodworking/forum/archives.pl/bid...

There is also CLT without glue, see my other comment. Check https://www.youtube.com/watch?v=4j_UjIshzMc.

"passive designs without active mechanical assistance" - do you mean passive (highly insulated, air tight) designs without mechanical ventilation?

Thanks, I follow Matt so I saw that, but couldn't figure out how they made the exterior wood stand up to the elements.

Yes, PassivHaus or even NetZero type standard, but without an electrically-powered ERV. I don't think it is possible, so I've been looking at minimizing the power requirements.

Using actual timbers in a place like Canada should be the norm. Many of the biggest trees are left after a clearcut because they're just too big. When everything around them is cut they tend to die quicker (due to exposure). If they do get cut and milled, they often get processed into dimensional lumber (2x4s) instead of being used as timber.

Also the power needed to grind clinker down to powder is huge, overall comminution (grinding) industrial processes are among the biggest electricity consumer in the world.

Cement ball mills are less than 1% efficiency.


Having done two postdocs in the field i can tell its not progressing very fast...

Is there any reason these facilities can’t source power using renewables PPAs?

Oh wow that is interesting! Thank you!

Is there a serious source ranking all global CO2 emissions? Where percentages add up to 100%?

I don't have the answer, but I can imagine this is hard to compile because so many things emit CO2 all over their supply chain. So the question becomes, when do you consider something the 'final' product in the line.

If it's cement, you presumably can't count 'construction' as it would be double-counted. Do you count an iPhone just during production? Or do you include shipping? If you include shipping, you can't have 'cargo ships' as it's own category.

I would argue cargo ships don’t need their own category in that case since they don’t exist for any other reason than to be part of the supply chain or other goods. All cargo ship pollution can be attributed to the cargo they’re transporting.

Collapsing all the categories will make it difficult to say things like "Using locally sourced construction materials will reduce our carbon emissions by x%," or "Our new SolarShip(tm) technology will reduce cargo ship emissions by y%, which amounts to z% of global emissions."

We don't need to eliminate categories, we just need to be clever in the way we present data. For example, there's nothing particularly difficult to understand in the statement "Cement is responsible for 8% of the world's CO2 emissions, half of which is from transportation, 1/3 of which is from cargo ships." If we likewise break down each category into its major sub-components, the sub-components can be recombined in different ways to produce a lot of interesting and actionable data. Having several charts side-by-side is much better than fighting over a single chart that doesn't add up to 100%.

There was an interesting pilot performed by SEI (Stockholm Environmental Institute) and UCL, using shipping data from Brazil, that tried to attribute shipping emissions to commodity type [0]

0: https://www.sei.org/publications/shipping-emissions-per-comm...

But ultimately the main purpose of such stat is to make policy decisions to reduce amount of greenhouse emissions, and so it should show effects of the both making cargo ships more emmision efficient and reducing amount of things people buy. So it's better to let it overlap.

Why would it be hard to compile? Costs over supply chains are calculated all the time. And we don't have to look at IPhones, we just have to look at the subset of processes that emit non-neglible amounts of CO2 regardless of if they are the final product or not.

The problem is deciding categories, and what to account for what and duplicate accounting of same operation in different sources and differences in accounting and not everybody doing it the exact same way and lack of transparency for sub-components. Think about making steel for wind turbines, or transporting sand for base of wind turbines. Both actions should be accounted on wind turbines co2 emissions, but also they should be accounted for transportation/steel industry and construction. Everything is interdependent. But lets put things in perspective what is ineffective, in Finland home electricity use is 7% of all energy products used in the country, and still people concentrate on that you should make marginal reductions in your electricity usage to reduce CO2 emissions.

Here is a pie chart (globally) from epa.gov: https://www.epa.gov/sites/production/files/2016-05/global_em...

Our World in Data is usually my go to for reliable data:


Meanwhile, there's a sand shortage: https://www.bbc.com/future/article/20191108-why-the-world-is...

Concrete might look very different in 25-50 years.

>Concrete might look very different in 25-50 years.

True more like it looked in 150 BC:


Bill Gates also mentioned he's now most worried about steel & cement in one of Mark Rober's videos: https://www.youtube.com/watch?v=-k-V3ESHcfA

That’s an attention grabbing headline number, but what it doesn’t tell you is what would alternatives mean in terms of co2 emissions?

Let’s say we take cement out or drastically reduce it. Where does co2 sit in increased consumption of viable alternatives.

I'm not quite understanding why the article should present alternatives. That's not what the article is really about. However, the article does present alternatives concerning the company BioMason.

Setting aside CO₂ concerns for a moment, I was explaining cement to a young child today and was suddenly struck by how marvelous cement is: It’s poured as a liquid yet solidifies into rock, and has been known since ancient times [1].

[1]: https://en.wikipedia.org/wiki/Cement#History

One question I've had about cement being a major source of CO2 emissions that I haven't seen addressed anywhere is that my understanding is as cement cures it does so by absorbing CO2 which is what turns it into rock.

Does this not cancel out the effect of making the cement in the first place? And if not, why not?

Would love to know if anyone has a good understanding.

While concrete does absorb CO2 there is a large misconception that it can absorb as much as is output during production. In reality any concrete worth its cost can only absorb a very small fraction of the production output.

A largely overlooked issue with the idea of concrete absorbing CO2 is exposed surface area. Imagine a hydro dam, one side is saturated with water, the other side is air. The dam is also usually quite thick, several meters to hundreds of meters. That really limits the available absorption surface especially considering the ratio of surface area to volume. Concrete foundations, epoxy coated parkades, even painted surfaces start to drastically reduce the possibility of CO2 being absorbed.

Think of concrete like a membrane or a sponge. The thicker the membrane you want to pass a fluid through, the higher the pressure you would require. So using our pressure as atmospheric, getting a high depth of CO2 absorption requires a well connected pore structure, and a long time frame.

Add to this membrane metaphor the issue of size. We design concrete structures to prevent fluid transfer, especially hydro dams! H2O is a smaller molecule than CO2, and the static pressure on the ‘wet’ side of a hydro dam increases 1 atmosphere every 10m.

As concrete sets and gains strength, its porosity decreases. This process happens rapidly in the first few days, and only ever stops when the cement runs out of free water to absorb. CO2 absorption depth is a pretty common test when evaluating a structure for rehabilitation purposes (carbonation dept testing) as CO2 will mess with the concrete PH and corrode reinforcing steel which (depending on many factors) can be as shallow as 5cm from the concrete surface. I’ve seen structures with up to 5cm of depth, but that is outside of the norm. 1-2cm of CO2 absorption depth for a structure from the 50’s is pretty common in my area.

Modern concrete, through many different means, has a highly disconnected pore structure (compared to the concrete of the 50’s). New concrete, is designed to reduce any type of fluid transfer especially after the first few days of curing. This will reduce the depth of CO2 absorption further.

So bringing this all back together, consider the absorption depth of 2cm, a structure with minimal exposed surface area, and some sort of coating or cladding… and you very quickly realize that you are not going to be off setting CO2 production outputs by any significant margin, and its not in your best interests either.

Thanks for the explanation, those are good points. Though wouldn't the interior concrete not harden if it wasn't able to absorb CO2, since my understanding is that's fundamental to the hardening process?

And agreed that surface area would effect the rate of absorption. I understand it can take hundreds of years for concrete to fully harden, which I could see being effected surface area and ability of the material to breath.

the crystals that form and bind the aggregate together are a hydrolysis reaction (water using). Water is the main reactant not CO2.

By the way, the bridge is part of the Brennerautobahn between South Tyrol in Italy and Innsbruck in Austria. The exact bridge is located in Italy.


Opentopomap: https://opentopomap.org/#map=13/46.93620/11.45582

I was looking for brick pavers recently and was having quite a time locating actual bricks instead of cement pavers colored badly and textured worse to look vaguely like bricks to nobody sober during daylight hours. I can only assume their target audience is a drunken man, at night, in a rainstorm.

I have to wonder why we are still looking for new ways to employ Portland cement at this point, over alternatives. You can, I’m told, reduce the footprint of clinker a bit with fly ash, but you get that mostly from coal, so it’s splitting the “savings” with an equally problematic cousin, and at any rate that supply should be in steady decline now, although I guess we discovered the Tennessee Valley Authority has stockpiles of the stuff when they lost one of them a decade or two ago.

> I was looking for brick pavers recently and was having quite a time locating actual bricks

I am not an American but I am not sure I have even seen a paver made from brick now that I think about it. I suspect the larger a brick is, the more chance of cracking.

So if it makes you feel any better, you probably would not find one in New Zealand either.

Seems clay pavers are still out there. Here's some in NZ:


But I don't think any national chains carry them anymore.

You can also supplement with iron slag cement and silica fume from iron and silicon production, respectively. Those are probably not going away.

False. It's common in volcanos. It's why Roman Cement is so good. That, salt water and pig blood.

It's also 11% of global anthropogenic mercury emissions.


TIL concrete and cement are not the same thing. The words are often used interchangeably, but that's apparently incorrect:


Crazy that quarrying and transport is less than 10% of the CO2 from Concrete.

Would living in tents reduce CO2 emissions? Is that preferable?

If you don't heat or cool them yes, it reduces CO2 emissions. No, it's not preferrable.

Wood, Straw Bale, Earth. This all works even in high rise building.

I live in a high rise building made out of concrete and know plenty of people who live in wood buildings. I'll pay double to not have to deal with the problems wood buildings have.

How often do you replace your tent? Does it come from china?

I’ve been touting this fact for years.

90% of landfill debris is from demolition.

We need more renovation instead of new construction.

"About 13 percent of the solid waste in Missouri landfills is demolition waste."

From page 128 of https://dnr.mo.gov/env/swmp/docs/wcs98constructionwaste.pdf

Debris is a type of solid waste.

I remember a while back reading about work on increasing the recycled content of concrete (using old concrete as aggregate in new concrete, I think?) but I did not bookmark it and none of my last set of searches seemed to be in the right direction.

There’s a Wikipedia page on the subject but little of it sounds familiar, and those bits have no citations.

Do you have a source for this?

“Demolition represents more than 90 percent of total C&D debris generation, while construction represents less than 10 percent.“


90% of construction and demolition debris is from demolition.

Not quite the same as your opener that claimed that it's 90% of all debris.

"Eliminate carbon dioxide, and plants would shrivel and die. So would lake and ocean phytoplankton, grasses, kelp and other water plants. After that, animal and human life would disappear. Even reducing CO2 levels too much – sending them back to pre-industrial levels, for example – would have terrible consequences for crops, other plants, animals and humans.": https://www.masterresource.org/carbon-dioxide/co2-gas-of-lif...

The minimum necessary CO2 level for plant life is about 100 ppm. That is a quarter of current levels. No plant life, no animal life, no life on the continents. Only a few chemeotroph bacteria survive.

The long term geobiological trend is for C02 to decrease through absorption by weathering rocks and burial of biogenic limestone in subduction zones. C02 was thought to be as much 50% early Earth. Then a percent or two in early Phanerozoic 400 million years ago. And natural about .025% in the current ice age.

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