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Sustainable energy without the hot air does this, it's a great book though I've heard it's somewhat outdated now.

The analytic approach is great, but the numbers are very out of date.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

https://apnews.com/article/56b7e682362016c1d97f094c2cde4a46

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.