At current rates of emissions, we’re only about 20 years away from people needing to install CO2 scrubbers in their homes.
Soda lime, or calcium hydroxide, is the current state of the art. We use that in an anesthesia and in saltwater aquariums and in scuba rebreathers. An idealized system can capture 500 mg per gram, but in practice you only capture around 250mg/g. This outperforms the method in the article but it’s one-shot. There are interesting proposals to use this for direct capture at industrial facilities and to turn the waste material into bricks for building.
The key advantage of this new material appears to be that it can be heated and reused. That would be very valuable in an interior direct air capture use case. Think about filtering the CO2 from an office or a home to get us back to pre-industrial levels indoors.
I think it’s little appreciated that high CO2 levels cause cognitive impairment, and with the same amount of (often very poor) air exchange, higher outdoor concentrations can push indoor spaces to levels that cause impaired cognition and poor sleep. I’ve already been seeing this in my home, and will often open windows even when cold just to keep co2 levels reasonable. One solution that can help is an external air heat exchanger, which can exchange air with the outdoors without compromising your homes heating and cooling like an open window will do.
Noticeable cognitive impairment starts in the 700-1000ppm range, whereas it is very common for homes to reach 2000-3000ppm, especially when in a closed bedroom.
> Noticeable cognitive impairment starts in the 700-1000ppm range
The US navy failed to detect such effects in submarine crew, even at much higher levels like 10,000 ppm.
Another reason to be skeptical is that exhaled breath is 4% CO2 (40,000 ppm!). Therefore a few thousand extra ppm in the inhaled air should not make much of a difference to the homeostasis mechanisms in our bodies.
>One solution that can help is an external air heat exchanger
I have one of those, it blows fresh air in through the bedroom and sucks it back out through the kitchen (loft house, this route prevents food smells from wafting into the bedroom). Aside from just feeling fresh all year, this system also prevents mosquitoes from entering in summer while still allowing air circulation, it automatically bypasses the exchanger at night to provide cool air and it has some pollen filters installed which helps with hay fever.
So great economic return and a bunch of upsides, but it does require space for the exchanger and the ducts throughout the house.
I have been monitoring for high CO2 for a few months now. I easily find myself in the 1000 - 1400 range for some time before I finally let some air in in winter.
I have not noticed significant cognitive impairment (not saying it did not happen)
I find it extremely unlikely that homes are routinely at 2000-3000 ppm. That is extremely high and would mean multiple people in a small area with no air exchange for a long while.
I monitor my indoor co2, but don't take any action because it's extremely rare to be above 700 or 800. I can only remember a handful of times its reached 1k ppm. And my house should be prime candidate for co2, it was built during the era of "seal all air gaps" but before ERV or HRVs. I also use pressurized co2 to inject co2 into a planted aquarium. And my dogs are terrified of open windows so they are rarely open.
My bedroom regularly gets to 3000 at night, and the flat in general is around 2000. This is in the winter, when I don't open the windows for days because of the cold. The flat is very well insulated.
I used an Awair Element after wondering if Co2 buildup was causing my groggieness in the morning and an ever so slight dull headache.
My bedroom was quite small at the time, but I measured the same effect of buildup in a larger bedroom, just the Co2 level took a little longer to reach it's peak.
In the small room it took about 45 mins to climb to about 1400 after I closed the door and went to sleep.
I'm currently trying to install some above-door vents to improve circulation but this is a topic most people don't consider at all, even though studies have shown the effects of classrooms having high Co2 concentrations on exam results and cognition.
> The ease of releasing CO2 is the key advantage of the new compound.
I have no idea why the journalist that wrote this article choose to highlight the carbon density of the sub-header. It's almost completely irrelevant for carbon capture plants.
Another clear benefit is that it's a liquid.
Today people mostly use the substances that you called non-reversible in research plants (AFAIK, all plants are research right now). They are perfectly reversible, but that uses a lot of energy.
> perfectly reversible, but that uses a lot of energy
Looks like a perfect match to a solar plant, which provides basically free energy periodically. All you need is a large enough cistern to hold the liquid during night time.
160F, non toxic, this already sounds like something that could feasibly be used in the home. I would already be interested in installing one. And would absolutely love to see what it would do to school performance.
Indoor is always higher ppm (how much depends on many parameters) without proper ventilation. „Proper“ should include a „Heat exchanger“ thus you don’t need to reheat fresh air.
Still, it will add some 80ppm over the amount you have today. There's a huge amount of disagreement over how much CO2 is harmful, but it tends to happen over numbers way above 800ppm.
If your room has 2 times the open air concentration, and you are concerned if it's 2.0 times or 2.2 times, you should already be dealing with the problem.
According to https://www.co2meter.com/blogs/news/carbon-dioxide-indoor-le..., at 1000 ppm people start getting drowsy. Let's assume that a decent indoor environment has 300 ppm more CO2 This means that our threshold for when people start getting drowsy even in decent indoor environments is when atmospheric CO2 reaches 700 ppm. For reference, it is currently around 420 ppm, and pre-industrial levels were 280 ppm.
The 300 ppm offset compared to the outside air is naturally just an arbitrary number, everything up to 1000 ppm (meaning everything up to 580 ppm more than atmospheric levels) is considered "acceptable". That means any increase in CO2 concentration will take an indoor environment which used to be considered "acceptable" and make it cross the threshold into "unacceptable". An indoor environment which would've been at 900 ppm around the industrial revolution (280 ppm) would've crossed the threshold when we surpassed 380 ppm (which was in 1965 according to https://www.statista.com/statistics/1091926/atmospheric-conc...).
let's compare the past 20 years. In 2004, the concentration was ~377 ppm. That's 47 ppm lower than what was in 2024. An indoor environment which was "borderline but acceptable" at 955 ppm CO2 in 2004 would've crossed the arbitrary 1000 ppm threshold by now, and therefore would benefit from a CO2 scrubber. The next 20 years will likely have a higher increase than the past 20 years, so there will be a larger range of currently acceptable indoor environments which will cross the 1000 ppm threshold by 2045.
TL;DR: It's complicated, 20 years is arbitrary, but as CO2 concentrations increase, indoor quality gets worse so indoor environments which were already bad will become worse. 45 years is a more realistic estimate for when your typical good indoor environment will become unacceptable, but it's a gradient.
I am not against doing research in this area, please do, it is interesting and likely has many applications but global CO2 removal isn't one of them. Nothing proposed, including this, is within any orders of magnitude of a viable solution. The only solution we have is put less in the air in the first place. This tech looks interesting for transporting CO2 but that doesn't mean it sequesters it and even if sequestration was solved the scales here are massive. If we don't have the political will to reduce the amount going into the air then what makes anyone think we would have the political will to build out some system to capture and sequester? We need to focus more on not putting CO2 into the air and less on trying to take it out.
I've wondered if capturing carbon emissions from industrial-scale compost facilities would be a net positive. It would have the added benefit of the carbon initially being captured by natural organic processes (i.e. growing food), so it avoids the problem of the energy requirements from trying to just pull carbon from the ambient atmosphere. I don't know if this is feasible but I haven't seen any research on it.
What we need to offset the last 3 centuries of coal use is to reverse the process. Plant large amounts of trees, cut them, burn the hydrogen part of them, producing char and reclaiming some energy, then bury the resulting coal back in the abandoned coal mines.
There are applications where weight still makes battery storage impossible. By capturing carbon, we may give ourselves the ability to harvest fuel from the air instead of the ground. Given the sometimes negative cost of electricity, this could make it more cost effective to do so. If we replace fossil fuel drilling with sequestration then we are at net zero.
This may be part of the solution … or maybe we find a way to make a utopia where we can all agree to just stop polluting. Historically, the utopia has no precedent that I am aware of.
> If we don't have the political will to reduce the amount going into the air then what makes anyone think we would have the political will to build out some system to capture and sequester?
Because political will requires coordination, building systems and turning them on doesn't have to!
> We need to focus more on not putting CO2 into the air and less on trying to take it out.
What part of the "we" in this coordination problem doesn't require political will?
The implicit model in "just emit less" is that human coordination problems are easier than engineering problems. That's historically backwards. We're extremely good at building things. We're terrible at getting everyone to sacrifice simultaneously for diffuse future benefits. Please generalize this!
Unfortunately, Technological solutions are more politically feasible than attempting to reduce via restrictions and regulations that require intense global coordination that does not exist.
There are 4 different categories of fixing the global CO2 challenge:
a. Remove CO2 from atmosphere
b. Prevent adding new CO2 from reaching atmosphere
This could also be a good use case for #b where CO2 is captured before being released to the atmosphere. For example factories and vehicles could be mandated to use this.
Maybe we need to genetically engineer special of trees that are active only during the day and sleep at night. Photosynthesis at daytime and Dormancy at nighttime for maximum CO2 conversion.
There's no general will, it's not specifically political will. Emitting less CO2 means doing less things or doing them for much more money due to high taxes to discourage it (and also disproportionately affect poor people). Other than some luddites I've never met anyone that genuinely was willing to sacrifice eating a nice steak or going on vacation unless they are millionaires, and that's only because those people know they can do it as much as they want. You have a huge mass of people getting lifted from poverty that will tell you to fuck off if you tell them that now they are finally out of eating rice and starving they can't have a steak, because of CO2.
All the things silicon valley "caviar communists" say you need to stop doing are basically the dreams of a whole mass of people coming out of poverty. Nice food, traveling, having a car, having A/C, etc.
So we can either find alternatives, or slowly figure out more geoengineering projects like mass absorbing CO2 and the like.
Well, instead of repeating myself manually, I'll paste in a comment of mine here from a past discussion on carbon capture:
It's easy to forget why there is a bit of a challenge to getting C02 out of the air: there's so little of it, comparatively.
In order, air is, broadly, made up of the following:
Nitrogen: %78.084
Oxygen: %20.946
Argon: %00.934
CO2: %00.042
The stuff is essentially beyond a rounding error - it really gives one an appreciation of the "either don't release it, or capture it at the point of release" sentiment, and for the difficulties in making carbon capture outside of these scenarios be even slightly cost-effective.
So then, is it really the CO2 that produces the cognitive impairment, or is the CO2 here just the proxy value that we are measuring, and the real reason for the cognitive impairment is low oxygen?
They don't, and they can't cheat physical realities either.
Plants only filter out very small amounts of CO2 from the air over relatively long timeframes. That's why crop-based biofuels require such enormous amounts of space.
I like the unconventional approach. A few minutes with GPT raises two issues:
1. We've raised CO2 from 280ppm to 420ppm, about a 50% increase. To dilute it back down would require 50% more total atmosphere. This would also raise the surface air pressure 1.5x.
2. How much heat is trapped is related to the absolute amount of CO2 in the atmosphere, not the fraction. So the diluted atmosphere would retain just as much heat.
Interesting thought but you would need a lot of these gasses on the one hand and on the other hand it doesn’t help in working against the greenhouse effect. The greenhouse effect depends on the absolute amount of CO2 in the atmosphere, not the percentage. How much infrared light is absorbed by CO2 primarily depends on the amount of CO2 in the atmosphere.
We will unquestionably reach more than twice the CO2 concentration of pre-industrial levels (which was around 280 ppm; we're at 424 ppm now, it'll increase to beyond 560 ppm in most not-super-optimistic projections).
Do you really think it's both feasible and a good idea to release so much O2 and N2 to double the mass of the atmosphere? Or even just increase it by some appreciable fraction?
For the record, the atmosphere is around 5 150 000 000 000 000 metric tons. 5 quintillion kilograms. You're talking about producing metric exatons of gas.
Wikipedia says that there's 300 000 to a million gigatons of nitrogen in the earth's crust; that's 300 teratons to a petaton (https://en.wikipedia.org/wiki/Nitrogen#Occurrence). If you extracted LITERALLY ALL THE NITROGEN IN THE CRUST, converted it to nitrogen gas and released it into the atmosphere, and we use the extremely optimistic 1 petaton estimate, you'd have increased the mass of the atmosphere by roughly 1/5000. That means you'd have decreased the CO2 concentration in the atmosphere ... by roughly 1/5000. From 424 ppm to 423.92 ppm.
Where else are they going to come from? They’re all basic elements, either you separate them from air, or you have to go through an energy intensive process to liberate them from various chemicals they’ve been compounded into.
But guess what, all of those chemicals are extremely valuable, such as nitrates for fertiliser, water, and Argon does really react with anything (it’s a noble gas), which is why we use it as a shield gas in processes like welding.
So producing enough of those gases to somehow offset CO2 production would first require ludicrously large amounts of energy, and if we had access to that amount of clean energy we wouldn’t even be having this discussion. Plus it requires breaking down really valuable chemicals that we spend quite a lot of energy trying to produce or preserve anyway.
Think about the magnitude you’re talking about here. Every internal combustion engine on earth is emitting CO2. Every volcano, forest fire, coal power plant, etc. The atmosphere is massive. We’ve been, basically, doing our best to pump it full of CO2 for the last 150 years, and this is what we’ve got. Ignoring the chemical challenges with your idea here, the scale is impossibly gargantuan.
Direct air capture imo can’t escape the scaling problem - when the feedstock has CO2 at ~400 ppm the economics simply won’t work out despite various oil companies backing one off systems around the globe.
Capturing CO2 at the source (power plant, etc) would be simpler to reach economic viability but without incentives it’s dead on arrival. I believe the IRA infra bill had put a price ~$50/ton of CO2 captured.
Capturing CO2 at the source will always be worse than removing the source. At the same time, capturing CO2 from the air will stay necessary until we do it.
But we still need to remove all the excess co2 that we released into the atmosphere since the start of the industrial revolution if we want to reduce the temperature back to what it was before we started disrupting the natural state of the plane.
We and previous generations took out a loan and the payment is coming due.
Because of the framing about degrees in celcius change people are thinking in small numbers, like "oh, it's just 1.5'C over normal. oops, we missed that, well maybe we'll get it at 2.0'C. They don't realize that if we want normal we ahve to reduce the temperaure and to do that we need to take that c02 blanket off that we've been tightly wrapping around our collective bodies for decades.
And that endeavor is nearly unfathomable. Think of all the energy used by humanity since the industrial revolution and the energy we're going to be producing in the time period that we attempt to sequester the previously poduced C02. All of that needs to be accounted for.
And then there's the surplus energy roiling around in the system now, and the collapse of food webs.
I don't see how we get our way out of this in the next 50 years.
With ice caps melted off, just removing all the excess CO2 isn't even enough since with that reflective surface gone, more energy from sunlight stays in the atmosphere than previously when more of it was reflected back into space instead of nowadays being absorbed by the ocean.
Absolutely. People seem to think that we just need to recycle more, seal some cracks in the house with foam, install some solar panels, and buy an electric car.
They underestimate the scale of the intervention that will be required to stave off the potential end of human civilization as we know it. If we have any hope of continuing to live at something resembling the quality of life that we've grown up in it will require radical science fiction like developments.
We're going to need things like space based solar shades to regrow glaciers and icepack, advanced breeding and cloning and ecosystem engineering to reconstruct collapsing food webs, and I think the big picture thing is that we're going to need to engineer people to reduce susceptibility to addictive food and manipulative marketing.
That’s true. It’s more of a policy issue that’s like carbon credits… nice on paper but a big nothing burger. Look at F1 and Porsche talking about sustainable synthetic fuels.
When you compare round trip efficiencies and economics it makes sense to just not burn the hydrocarbons to begin with.
If stored near a populated area, hundreds of thousands could be kill, including all animals and insects, in a matter of minutes if the "vault" has a catastrophic failure. I would rather live near a nuclear waste site than a CO2 Site.
Well as far as storing it goes, if you can capture it, turn it into a solid and stick it in the ground.
Imagine you were growing a huge biomass that you harvest, dry out, and then store. We know how the bacteria and processes that stripped co2 from the atmosphere in the past, we just need to do that in a big way. Good thing we have places on earth that are huge and flat and growing algae won't be a problem.
And then we complement that with green energy and an attempt at net zero.
One thought I had was to go a very cold place and freeze CO₂ out of the air, about -80°C.
There’s the katabatic winds off of the glaciers in Greenland and Antarctica, which could help things go through.
But I soon realised that CO₂ is so potent, that it’s so such a small proportion of the air that not much would be taken out.
There’s some renewable storage systems that liquify air, that could remove CO₂ but they don’t mention it;,but air liquification doesn’t seem to be growing fast as an option.
The other one from mere A-level chemistry is buffer solutions and using chemical reactions in the Oceans, apart from iron seeding for life, but a chemical that precipitate an insoluble carbonate.
Not ideal raining down precipitates, or using the Ocean as a test tube.
And the superbase is 1,5,7-triazabicyclo [4.3.0] non-6-ene
It is an anime based technology. Other amines in water-based solutions also get regenerated at about <200C. It is great to find new molecules to do this work but as I usual, these marketing articles sensationalize the actual work.
A better title would be "More efficient method to capture CO2 from the atmosphere." The method is not objectively efficient, but may be more efficient than other methods (solvents/sorbents) used for DAC.
I gave my engineering students a CO2 removal design problem once, and at the end, asked why the theoretical efficiency had increased in the time since the textbook was written. The answer was that the concentration of CO2 in the atmosphere was higher.
Economics rules everything. How much does this cost vs simply planting trees, when the value of harvesting the trees is included? Since tree farms are generally profitable, and wood is expensive, it seems this method is likely to be economically less efficient.
The problem is you cannot plant enough trees around the globe to offset our CO2 emissions.
Also, a forest only absorbs CO2 while alive. Once it dies, it emits CO2 too.
You would need to permanently store the wood somewhere (submerging in water, etc).
You don’t need to convert it to coal. Use it to build houses, furniture, and other things.
I am currently building a wooden house this way. Wooden frame, wooden exterior, wooden floors, even wood-based insulation (https://huntonfiber.co.uk/). The isolation has the shortest life span and it is expected to last at least 60 years.
If these forests are planted by humans, why do we think the dead trees would just be left to rot like you suggest vs being harvested for wood? The logic does not compute other than trying to make a ridiculous point.
One little appreciated fact is that trees also respirate CO2 when they are cracking their stored sugars produced via photosynthesis. So they don’t sequester all of the CO2 that they consume.
I suppose I’m pointing it out to highlight the trade offs with any of these solutions.
What is unsaid is that we need to sequester CO2 for hundreds of years—often far beyond the lifespan of the trees. Trees are short term storage, and sometimes the storage is a lot shorter than popular imagination purports.
It's a hugely underappreciated option. I'm not sure how accurate it is (or how legitimate the companies doing biochar carbon removal are), but cdr.fyi shows biochar as the top carbon sequestration method that's actually happening.
Physics rules everything, once you start trying to run at scale.
The density of carbon per unit volume in solid materials of interest doesn't vary that much, whether you sink it in trees or in exotic materials like diamonds. That means you can calculate the volume of material required so sink a desired amount of atmospheric carbon.
If you want to have a measurable impact on the atmosphere, say dialing it back to 1980 CO2 levels, you're talking not about making a pile of stuff but about making a mountain range that's a mile high and hundreds of miles long.
Now figure out how many trucks you're going to need to move that much material from where your sequestering machine is to where your pile of stuff is.
Or if you want to dump that material in the ocean (which someone else will certainly object to), extend your calculation to figure out how many container trucks worth of material you need to dump into the ocean every hour to accomplish your atmospheric cleanup in whatever amount of time you choose (a decade? If it takes a century, that's not fast enough).
And finally think about surface to volume ratios. You're trying to sink it into a volume, but you can only get the gas into the volume through its surface, so the speed of your process is limited by surface area.
If you want to do it with trees,
my personal spitball estimates are that you probably need to plant somewhere between the entire state of Connecticut and the entire state of Colorado to have the kind of impact one would want (there's more subtlety to tree calculations than one generally likes to admit, so feel free to come in with way higher numbers than I did).
Which brings us back to economics. If you have a well-managed forest of that size and scale, someone is eventually going to come along, maybe in 100 years, maybe in 500 years, and say "hey if we cut this down, we could burn the wood to heat our homes" and all that carbon goes back into the atmosphere, so you actually need to sink it into something that is energetically unfavorable for recovery, which means you also need to expand a huge amount of energy to sink the carbon into that energetically unfavorable state.
> you're talking not about making a pile of stuff but about making a mountain range that's a mile high and hundreds of miles long.
Just to put it into numbers, wikipedia has the total amount of CO2 on the global warming page, if we assume it's in a 2 g/l substance it totals to around 180 km^3.
But if you release the O2 and convert it into diamond, then by my highy-suspect back of the envelope calculations, it'd be a diamond that would fit into one square kilometer, 87 meters high. It would make quite the tourist attraction.
1. Even if we do magic and emit nothing, we still need to remove CO2 from the atmosphere or it will cook us over time, just longer.
2. We would need an enormous area for forests (which i great), which would mean a lot of intervention, like resettling people, demolishing and constructing new buildings, a lot of machinery time to move people to and from the new forests, a lot of planting and forest maintenance involved. And add he work to cut and bury resulting wood. If you would sum all the incidental emissions from this process it would rapidly become much less efficient (if at all).
Without either CO2 capture or a sun shade of some sort, the CO2 levels and temperature will only ever increase, just like now.
I agree. Plants are not very efficient (1% or 2%) but they include packaging the CO2 in a stable form. You can store the grain or wood for long periods of times.
In this case, it looks like they get CO2 as a gas. It's cheaper because you don't have to use energy to undo the burning, but it's difficult to store for a long time.
(I'm not sure if someone tried to make a fake underground bog in abandoned mine. Just fill with wood and water to keep the oxygen low and make the wood decompose slowly.)
Take a look at "wood vault".
'Wood vaulting': A simple climate solution you’ve probably never heard of | Grist https://share.google/lS8xnMGEd1pMzlNg2
Economically not attractive but apparently very efficient in locking up CO2.
The problem with any scheme to capture and store carbon from the atmosphere is the incredible amount of carbon we've blown into the air in the last 150 years. Just look at the size of the machines we use to harvest coal. Essentially you'd need to have machines of similar size working for many decades to re-bury the carbon we extracted and burned. Who's gonna pay for that?
Planting trees is not effective since it takes decades to capture the carbon, but the next years are crucial for determining long term climate developments.
There is no carbon capture technology on earth that can be rolled out at a scale over the next few years that can compete with planting trees. Especially not one that has just been invented in one university. Ash grows 90cm per year, that's all carbon. Scale that to millions and billions.
Without knowing much about the details of it, this might be interesting to evaluate as a potentially economically more attractive alternative to DAC in the supply chain of e-fuel production?
Just use lye to baking soda. You could in theory make an efficient roundtrip.
Anyway - CO2 in the atmosphere is here to stay. Much more "realistic" approach is to decarbonize the ocean and let the ocean absorb the atmospheric CO2.
That's the first thing I thought when I read the title.
Hey we have already efficient systems for eliminating CO2 from the athmosphere: trees!. The joke tells itself.
It seems like we have not yet done the full circle, but we are close.
The thing people don't think about with regards to CO2 capture is that you have to get the atmosphere in order to capture CO2 from it. You essentially have to suck the entire atmosphere into these carbon capture facilities.
Using something like this to capture carbon from an exhaust pipe might be viable, but scrubbing CO2 out of the atmosphere is not even remotely viable. There's just too much air out there.
You can actually capture CO2 from sea water thereby reducing ocean acidification and improving its capability to continue as our planets biggest CO2 sink.
You're right, it's expensive and hard, so it's better to not do anything and... migrate all humanity onto space stations so we don't die with the earth, I guess is the alternative you're suggesting?
On a much smaller scale I've been hoping for a small solar powered CO2 compressor to exist so I could use it for mosquito traps. The state of the art for those right now is burning propane for the CO2 combined with a scent emitter for the human smell to attract female mosquitos.
You can think of industrial CO2 use as basically the same as nitrogen but a little worse and several fucktons cheaper.
CO2 is fairly inert. This makes it useful. Welding steel is a typical example of something you can use CO2 to shield. There are many other examples in the chemicals industries of things like that where you want to do something at a "higher than natural on earth" temperature to make a reaction happen or happen faster but you don't want that reaction to happen with oxygen all around.
And on the other end of the temperature spectrum....dry ice.
This solves only part of the problem: it captures CO2 and can release it later. But you still need to figure out what to do with this CO2, how to turn it into something useful.
you can inject it into peridotites and let it mineralize. there is enough exposed peridotite outcrops in the world that we could inject all the co2 produced and store it there indefinitely. this process also produces elemental hydrogen.
This is more about the mechanics of how the rock breaks to allow fluids to move around.
And here is another paper currently in review that we coauthored about how we know there’s gas moving in the system and therefore hydrogen is being produced:
Someone proposed to make giant beaches of malachite and let the sea break the rocks. Malachite has two -OH that can be replaced by a CO3= and so capture the CO2.
I can't find a good link now, but at least it's the only method I know where it's not obvious that requires a huge amount of energy that makes the whole process net negative.
Their process for generating potassium formate is greener than standard methods. It does require electricity as an input but that can come from renewable, green sources.
Potassium formate is used in de-icing products, fertilizer, heat transfer fluids, drilling fluid, etc... so a useful, monetizeable output comes out of the process.
Disclosure - Know the founders personally. Wanted to shoutout their work. No financial ties to the company.Chemistry is not at all my expertise & I don't have details on their process beyond what's on the website.
I'm fine with keeping it inside something brick-shaped and chucking it down an abandoned mine from where it can be retrieved at a later time. It would definitely be a storage improvement over "the atmosphere and our lungs".
Stable storage would be limestone. To bring it down to pre-industrial levels it would mean that each person on earth would get a cube of 5 meters a side.
IDK, build houses out of limestone like we have been doing for ages.
The answer is obvious: create a cryptocurrency-based economy where countries and citizens are incentivized to pull CO2 out of the atmosphere and ship it into space in exchange for crypto.
/s
One of the subplots from the excellent Delta-V series by Daniel Suarez.
At current rates of emissions, we’re only about 20 years away from people needing to install CO2 scrubbers in their homes.
Soda lime, or calcium hydroxide, is the current state of the art. We use that in an anesthesia and in saltwater aquariums and in scuba rebreathers. An idealized system can capture 500 mg per gram, but in practice you only capture around 250mg/g. This outperforms the method in the article but it’s one-shot. There are interesting proposals to use this for direct capture at industrial facilities and to turn the waste material into bricks for building.
The key advantage of this new material appears to be that it can be heated and reused. That would be very valuable in an interior direct air capture use case. Think about filtering the CO2 from an office or a home to get us back to pre-industrial levels indoors.
I think it’s little appreciated that high CO2 levels cause cognitive impairment, and with the same amount of (often very poor) air exchange, higher outdoor concentrations can push indoor spaces to levels that cause impaired cognition and poor sleep. I’ve already been seeing this in my home, and will often open windows even when cold just to keep co2 levels reasonable. One solution that can help is an external air heat exchanger, which can exchange air with the outdoors without compromising your homes heating and cooling like an open window will do.
Noticeable cognitive impairment starts in the 700-1000ppm range, whereas it is very common for homes to reach 2000-3000ppm, especially when in a closed bedroom.
> Noticeable cognitive impairment starts in the 700-1000ppm range
The US navy failed to detect such effects in submarine crew, even at much higher levels like 10,000 ppm.
Another reason to be skeptical is that exhaled breath is 4% CO2 (40,000 ppm!). Therefore a few thousand extra ppm in the inhaled air should not make much of a difference to the homeostasis mechanisms in our bodies.
>One solution that can help is an external air heat exchanger
I have one of those, it blows fresh air in through the bedroom and sucks it back out through the kitchen (loft house, this route prevents food smells from wafting into the bedroom). Aside from just feeling fresh all year, this system also prevents mosquitoes from entering in summer while still allowing air circulation, it automatically bypasses the exchanger at night to provide cool air and it has some pollen filters installed which helps with hay fever.
So great economic return and a bunch of upsides, but it does require space for the exchanger and the ducts throughout the house.
I have been monitoring for high CO2 for a few months now. I easily find myself in the 1000 - 1400 range for some time before I finally let some air in in winter.
I have not noticed significant cognitive impairment (not saying it did not happen)
> higher outdoor concentrations can push indoor spaces to levels that cause impaired cognition
I am somewhat skeptical of this:
https://www.astralcodexten.com/p/eight-hundred-slightly-pois...
> high CO2 levels cause cognitive impairment
Sounds seriously unlikely. How would this work in practice, at the level of bodily functions?
I don't know the mechanism, but: https://www.google.com/search?q=co2+cognitive+impairment
Really? Wow, I try to keep my place at 500-600, without that much effort.
I find it extremely unlikely that homes are routinely at 2000-3000 ppm. That is extremely high and would mean multiple people in a small area with no air exchange for a long while.
I monitor my indoor co2, but don't take any action because it's extremely rare to be above 700 or 800. I can only remember a handful of times its reached 1k ppm. And my house should be prime candidate for co2, it was built during the era of "seal all air gaps" but before ERV or HRVs. I also use pressurized co2 to inject co2 into a planted aquarium. And my dogs are terrified of open windows so they are rarely open.
My bedroom regularly gets to 3000 at night, and the flat in general is around 2000. This is in the winter, when I don't open the windows for days because of the cold. The flat is very well insulated.
Homes in the upper midwest are well-sealed and insulated. Bedrooms can hit 2,000 ppm with two adults sleeping in them.
If we are three in my small living room in winter (around 20m2), it easily climbs above to 2000ppm in less than an hour
Ok this sounds like BS, what kind of sensor is being used to get such readings? What do you use?
I used an Awair Element after wondering if Co2 buildup was causing my groggieness in the morning and an ever so slight dull headache.
My bedroom was quite small at the time, but I measured the same effect of buildup in a larger bedroom, just the Co2 level took a little longer to reach it's peak.
In the small room it took about 45 mins to climb to about 1400 after I closed the door and went to sleep.
I'm currently trying to install some above-door vents to improve circulation but this is a topic most people don't consider at all, even though studies have shown the effects of classrooms having high Co2 concentrations on exam results and cognition.
We monitor air data quite closely at work.
CO2 rises really fast with people in even a large space.
I wouldn’t put too much effort into vents above a door as we’ve seen that CO2 will leak through doors and even floors/ceilings very quickly.
> The ease of releasing CO2 is the key advantage of the new compound.
I have no idea why the journalist that wrote this article choose to highlight the carbon density of the sub-header. It's almost completely irrelevant for carbon capture plants.
Another clear benefit is that it's a liquid.
Today people mostly use the substances that you called non-reversible in research plants (AFAIK, all plants are research right now). They are perfectly reversible, but that uses a lot of energy.
> perfectly reversible, but that uses a lot of energy
Looks like a perfect match to a solar plant, which provides basically free energy periodically. All you need is a large enough cistern to hold the liquid during night time.
160F, non toxic, this already sounds like something that could feasibly be used in the home. I would already be interested in installing one. And would absolutely love to see what it would do to school performance.
The hard part is capture and disposal.
Could something like this be used to make cement?
Imagine capturing CO2 to turn it into cement, used for constructions.
Pardon my ignorance, though.
We don't use CO2 to make cement, we use limestone, and CO2 is the byproduct of heating the limestone to make reactive calcium.
Do you have a citation for that 20 years estimate?
https://gml.noaa.gov/ccgg/trends/
Extending the current exponential for 20 years, we get into the 500ppm region.
I don't think that's enough to need scrubbers.
Indoor is always higher ppm (how much depends on many parameters) without proper ventilation. „Proper“ should include a „Heat exchanger“ thus you don’t need to reheat fresh air.
Still, it will add some 80ppm over the amount you have today. There's a huge amount of disagreement over how much CO2 is harmful, but it tends to happen over numbers way above 800ppm.
If your room has 2 times the open air concentration, and you are concerned if it's 2.0 times or 2.2 times, you should already be dealing with the problem.
According to https://www.co2meter.com/blogs/news/carbon-dioxide-indoor-le..., at 1000 ppm people start getting drowsy. Let's assume that a decent indoor environment has 300 ppm more CO2 This means that our threshold for when people start getting drowsy even in decent indoor environments is when atmospheric CO2 reaches 700 ppm. For reference, it is currently around 420 ppm, and pre-industrial levels were 280 ppm.
From https://www.climate.gov/news-features/understanding-climate/..., the pessimistic projections suggest that we may reach our 700 ppm threshold by roughly 2070; 45 years from now. (The graphs are hard to read precisely)
The 300 ppm offset compared to the outside air is naturally just an arbitrary number, everything up to 1000 ppm (meaning everything up to 580 ppm more than atmospheric levels) is considered "acceptable". That means any increase in CO2 concentration will take an indoor environment which used to be considered "acceptable" and make it cross the threshold into "unacceptable". An indoor environment which would've been at 900 ppm around the industrial revolution (280 ppm) would've crossed the threshold when we surpassed 380 ppm (which was in 1965 according to https://www.statista.com/statistics/1091926/atmospheric-conc...).
let's compare the past 20 years. In 2004, the concentration was ~377 ppm. That's 47 ppm lower than what was in 2024. An indoor environment which was "borderline but acceptable" at 955 ppm CO2 in 2004 would've crossed the arbitrary 1000 ppm threshold by now, and therefore would benefit from a CO2 scrubber. The next 20 years will likely have a higher increase than the past 20 years, so there will be a larger range of currently acceptable indoor environments which will cross the 1000 ppm threshold by 2045.
TL;DR: It's complicated, 20 years is arbitrary, but as CO2 concentrations increase, indoor quality gets worse so indoor environments which were already bad will become worse. 45 years is a more realistic estimate for when your typical good indoor environment will become unacceptable, but it's a gradient.
https://en.wikipedia.org/wiki/Carbon_dioxide_in_the_atmosphe...
Just extrapolate.
I was also a bit skeptical, but chatgpt gave a pretty good answer I think: https://chatgpt.com/share/69553e26-ea28-8011-bc17-8658fbea4e...
Buildings with higher people/sqft could already take advantage of indoor co2 scrubbers today.
You can heat definitely heat NaHCO3 to get CO2 and NaOH back. It just takes a lot of energy.
citation for the co2 scrubbers in home need?
Maybe we just need to make cyanobacteria that multiplies faster.
I am not against doing research in this area, please do, it is interesting and likely has many applications but global CO2 removal isn't one of them. Nothing proposed, including this, is within any orders of magnitude of a viable solution. The only solution we have is put less in the air in the first place. This tech looks interesting for transporting CO2 but that doesn't mean it sequesters it and even if sequestration was solved the scales here are massive. If we don't have the political will to reduce the amount going into the air then what makes anyone think we would have the political will to build out some system to capture and sequester? We need to focus more on not putting CO2 into the air and less on trying to take it out.
Sequestering CO2 where it's highly concentrated, e.g. at power plants or cement factories exhausts, would be one way to emit less.
I've wondered if capturing carbon emissions from industrial-scale compost facilities would be a net positive. It would have the added benefit of the carbon initially being captured by natural organic processes (i.e. growing food), so it avoids the problem of the energy requirements from trying to just pull carbon from the ambient atmosphere. I don't know if this is feasible but I haven't seen any research on it.
What we need to offset the last 3 centuries of coal use is to reverse the process. Plant large amounts of trees, cut them, burn the hydrogen part of them, producing char and reclaiming some energy, then bury the resulting coal back in the abandoned coal mines.
There are applications where weight still makes battery storage impossible. By capturing carbon, we may give ourselves the ability to harvest fuel from the air instead of the ground. Given the sometimes negative cost of electricity, this could make it more cost effective to do so. If we replace fossil fuel drilling with sequestration then we are at net zero.
This may be part of the solution … or maybe we find a way to make a utopia where we can all agree to just stop polluting. Historically, the utopia has no precedent that I am aware of.
We'll need this tech later. If and when we get emissions to net zero we'll still have too much CO2 in the air. Better to have begun the research now.
> If we don't have the political will to reduce the amount going into the air then what makes anyone think we would have the political will to build out some system to capture and sequester?
Because political will requires coordination, building systems and turning them on doesn't have to!
> We need to focus more on not putting CO2 into the air and less on trying to take it out.
What part of the "we" in this coordination problem doesn't require political will?
The implicit model in "just emit less" is that human coordination problems are easier than engineering problems. That's historically backwards. We're extremely good at building things. We're terrible at getting everyone to sacrifice simultaneously for diffuse future benefits. Please generalize this!
Unfortunately, Technological solutions are more politically feasible than attempting to reduce via restrictions and regulations that require intense global coordination that does not exist.
There are 4 different categories of fixing the global CO2 challenge: a. Remove CO2 from atmosphere b. Prevent adding new CO2 from reaching atmosphere
This could also be a good use case for #b where CO2 is captured before being released to the atmosphere. For example factories and vehicles could be mandated to use this.
Maybe we need to genetically engineer special of trees that are active only during the day and sleep at night. Photosynthesis at daytime and Dormancy at nighttime for maximum CO2 conversion.
We need this even if emissions went to zero overnight. World is a big place, can do more than one thing at a time.
There's no general will, it's not specifically political will. Emitting less CO2 means doing less things or doing them for much more money due to high taxes to discourage it (and also disproportionately affect poor people). Other than some luddites I've never met anyone that genuinely was willing to sacrifice eating a nice steak or going on vacation unless they are millionaires, and that's only because those people know they can do it as much as they want. You have a huge mass of people getting lifted from poverty that will tell you to fuck off if you tell them that now they are finally out of eating rice and starving they can't have a steak, because of CO2.
All the things silicon valley "caviar communists" say you need to stop doing are basically the dreams of a whole mass of people coming out of poverty. Nice food, traveling, having a car, having A/C, etc.
So we can either find alternatives, or slowly figure out more geoengineering projects like mass absorbing CO2 and the like.
Well, instead of repeating myself manually, I'll paste in a comment of mine here from a past discussion on carbon capture:
It's easy to forget why there is a bit of a challenge to getting C02 out of the air: there's so little of it, comparatively.
In order, air is, broadly, made up of the following:
Nitrogen: %78.084
Oxygen: %20.946
Argon: %00.934
CO2: %00.042
The stuff is essentially beyond a rounding error - it really gives one an appreciation of the "either don't release it, or capture it at the point of release" sentiment, and for the difficulties in making carbon capture outside of these scenarios be even slightly cost-effective.
So then, is it really the CO2 that produces the cognitive impairment, or is the CO2 here just the proxy value that we are measuring, and the real reason for the cognitive impairment is low oxygen?
Indeed. Have a look at a comment I made some time ago on this topic: https://news.ycombinator.com/item?id=40693024
If the amount of CO2 is basically a rounding error, so too would be the reduction in oxygen.
Plants seem to manage it okay.
They don't, and they can't cheat physical realities either.
Plants only filter out very small amounts of CO2 from the air over relatively long timeframes. That's why crop-based biofuels require such enormous amounts of space.
What if one started emitting Nitrogen, Oxygen and Argon in the right proportions instead to get the mix right again?
I like the unconventional approach. A few minutes with GPT raises two issues:
1. We've raised CO2 from 280ppm to 420ppm, about a 50% increase. To dilute it back down would require 50% more total atmosphere. This would also raise the surface air pressure 1.5x.
2. How much heat is trapped is related to the absolute amount of CO2 in the atmosphere, not the fraction. So the diluted atmosphere would retain just as much heat.
Would it increase the surface air pressure by 50%, or would more molecules offgas into outer space to compensate?
If the latter, it might actually work. Assuming they offgas at-proportion. Which they probably wouldn’t…
Interesting thought but you would need a lot of these gasses on the one hand and on the other hand it doesn’t help in working against the greenhouse effect. The greenhouse effect depends on the absolute amount of CO2 in the atmosphere, not the percentage. How much infrared light is absorbed by CO2 primarily depends on the amount of CO2 in the atmosphere.
We will unquestionably reach more than twice the CO2 concentration of pre-industrial levels (which was around 280 ppm; we're at 424 ppm now, it'll increase to beyond 560 ppm in most not-super-optimistic projections).
Do you really think it's both feasible and a good idea to release so much O2 and N2 to double the mass of the atmosphere? Or even just increase it by some appreciable fraction?
For the record, the atmosphere is around 5 150 000 000 000 000 metric tons. 5 quintillion kilograms. You're talking about producing metric exatons of gas.
Wikipedia says that there's 300 000 to a million gigatons of nitrogen in the earth's crust; that's 300 teratons to a petaton (https://en.wikipedia.org/wiki/Nitrogen#Occurrence). If you extracted LITERALLY ALL THE NITROGEN IN THE CRUST, converted it to nitrogen gas and released it into the atmosphere, and we use the extremely optimistic 1 petaton estimate, you'd have increased the mass of the atmosphere by roughly 1/5000. That means you'd have decreased the CO2 concentration in the atmosphere ... by roughly 1/5000. From 424 ppm to 423.92 ppm.
My naive guess is that since CO2 takes up so few percentage, you would need an unfathomable amount of N, O, and Ar to get the mix right..?
These gases are refined from air to begin with.
Do they need to be?
Where else are they going to come from? They’re all basic elements, either you separate them from air, or you have to go through an energy intensive process to liberate them from various chemicals they’ve been compounded into.
But guess what, all of those chemicals are extremely valuable, such as nitrates for fertiliser, water, and Argon does really react with anything (it’s a noble gas), which is why we use it as a shield gas in processes like welding.
So producing enough of those gases to somehow offset CO2 production would first require ludicrously large amounts of energy, and if we had access to that amount of clean energy we wouldn’t even be having this discussion. Plus it requires breaking down really valuable chemicals that we spend quite a lot of energy trying to produce or preserve anyway.
Where would that come from? It's not that we have some large untapped Oxygen or Nitrogen source laying around that is not part of the atmosphere.
Think about the magnitude you’re talking about here. Every internal combustion engine on earth is emitting CO2. Every volcano, forest fire, coal power plant, etc. The atmosphere is massive. We’ve been, basically, doing our best to pump it full of CO2 for the last 150 years, and this is what we’ve got. Ignoring the chemical challenges with your idea here, the scale is impossibly gargantuan.
Direct air capture imo can’t escape the scaling problem - when the feedstock has CO2 at ~400 ppm the economics simply won’t work out despite various oil companies backing one off systems around the globe.
Capturing CO2 at the source (power plant, etc) would be simpler to reach economic viability but without incentives it’s dead on arrival. I believe the IRA infra bill had put a price ~$50/ton of CO2 captured.
Capturing CO2 at the source will always be worse than removing the source. At the same time, capturing CO2 from the air will stay necessary until we do it.
But we still need to remove all the excess co2 that we released into the atmosphere since the start of the industrial revolution if we want to reduce the temperature back to what it was before we started disrupting the natural state of the plane.
We and previous generations took out a loan and the payment is coming due.
Because of the framing about degrees in celcius change people are thinking in small numbers, like "oh, it's just 1.5'C over normal. oops, we missed that, well maybe we'll get it at 2.0'C. They don't realize that if we want normal we ahve to reduce the temperaure and to do that we need to take that c02 blanket off that we've been tightly wrapping around our collective bodies for decades.
And that endeavor is nearly unfathomable. Think of all the energy used by humanity since the industrial revolution and the energy we're going to be producing in the time period that we attempt to sequester the previously poduced C02. All of that needs to be accounted for.
And then there's the surplus energy roiling around in the system now, and the collapse of food webs.
I don't see how we get our way out of this in the next 50 years.
With ice caps melted off, just removing all the excess CO2 isn't even enough since with that reflective surface gone, more energy from sunlight stays in the atmosphere than previously when more of it was reflected back into space instead of nowadays being absorbed by the ocean.
Absolutely. People seem to think that we just need to recycle more, seal some cracks in the house with foam, install some solar panels, and buy an electric car.
They underestimate the scale of the intervention that will be required to stave off the potential end of human civilization as we know it. If we have any hope of continuing to live at something resembling the quality of life that we've grown up in it will require radical science fiction like developments.
We're going to need things like space based solar shades to regrow glaciers and icepack, advanced breeding and cloning and ecosystem engineering to reconstruct collapsing food webs, and I think the big picture thing is that we're going to need to engineer people to reduce susceptibility to addictive food and manipulative marketing.
That’s true. It’s more of a policy issue that’s like carbon credits… nice on paper but a big nothing burger. Look at F1 and Porsche talking about sustainable synthetic fuels.
When you compare round trip efficiencies and economics it makes sense to just not burn the hydrocarbons to begin with.
Yes
For the atmospheric one, grow trees and algae
I agree, plus were would one store the CO2 ? To get back to "1980", I really doubt puling CO2 from the atmosphere will ever work.
Another concern, who will pay for maintenance ? See this for why you cannot let CO2 escape from underground storage:
https://en.wikipedia.org/wiki/Lake_Nyos_disaster
If stored near a populated area, hundreds of thousands could be kill, including all animals and insects, in a matter of minutes if the "vault" has a catastrophic failure. I would rather live near a nuclear waste site than a CO2 Site.
Can't we just store C and let the O2 back in the air like plants do? We could store it right where it came from, in old coal mines.
> I would rather live near a nuclear waste site than a CO2 Site.
If it's between immediate death and a slow one of cancer, I'm not sure your choice is the obvious one.
Well as far as storing it goes, if you can capture it, turn it into a solid and stick it in the ground.
Imagine you were growing a huge biomass that you harvest, dry out, and then store. We know how the bacteria and processes that stripped co2 from the atmosphere in the past, we just need to do that in a big way. Good thing we have places on earth that are huge and flat and growing algae won't be a problem.
And then we complement that with green energy and an attempt at net zero.
As long as leading figures either claim it's a hoax or that it's not necessary to do sth about it, none of this matters anywhere.
This is less of a technogical problem than it is a political one, I'm afraid.
One thought I had was to go a very cold place and freeze CO₂ out of the air, about -80°C.
There’s the katabatic winds off of the glaciers in Greenland and Antarctica, which could help things go through.
But I soon realised that CO₂ is so potent, that it’s so such a small proportion of the air that not much would be taken out.
There’s some renewable storage systems that liquify air, that could remove CO₂ but they don’t mention it;,but air liquification doesn’t seem to be growing fast as an option.
The other one from mere A-level chemistry is buffer solutions and using chemical reactions in the Oceans, apart from iron seeding for life, but a chemical that precipitate an insoluble carbonate. Not ideal raining down precipitates, or using the Ocean as a test tube.
This seems like the actual work of the article: https://pubs.acs.org/doi/10.1021/acs.est.5c13908
And the superbase is 1,5,7-triazabicyclo [4.3.0] non-6-ene
It is an anime based technology. Other amines in water-based solutions also get regenerated at about <200C. It is great to find new molecules to do this work but as I usual, these marketing articles sensationalize the actual work.
I would’ve expected the research to be coming out of Japan if it’s an anime based technology ;)
A better title would be "More efficient method to capture CO2 from the atmosphere." The method is not objectively efficient, but may be more efficient than other methods (solvents/sorbents) used for DAC.
I gave my engineering students a CO2 removal design problem once, and at the end, asked why the theoretical efficiency had increased in the time since the textbook was written. The answer was that the concentration of CO2 in the atmosphere was higher.
Yes it's important to distinguish "efficiency getting closer to theoretical maximum" from "actually cheap and economically feasible".
Economics rules everything. How much does this cost vs simply planting trees, when the value of harvesting the trees is included? Since tree farms are generally profitable, and wood is expensive, it seems this method is likely to be economically less efficient.
The problem is you cannot plant enough trees around the globe to offset our CO2 emissions. Also, a forest only absorbs CO2 while alive. Once it dies, it emits CO2 too. You would need to permanently store the wood somewhere (submerging in water, etc).
Recent article: https://www.theguardian.com/environment/2025/nov/28/africa-f...
It's possible to permanently capture the carbon if you turn the wood into charcoal and ultimately bury or store that.
But left out to rot and yeah, the fungus and bacteria will ultimately consume the wood and release CO2 as a byproduct.
You don’t need to convert it to coal. Use it to build houses, furniture, and other things.
I am currently building a wooden house this way. Wooden frame, wooden exterior, wooden floors, even wood-based insulation (https://huntonfiber.co.uk/). The isolation has the shortest life span and it is expected to last at least 60 years.
If these forests are planted by humans, why do we think the dead trees would just be left to rot like you suggest vs being harvested for wood? The logic does not compute other than trying to make a ridiculous point.
One little appreciated fact is that trees also respirate CO2 when they are cracking their stored sugars produced via photosynthesis. So they don’t sequester all of the CO2 that they consume.
It's little appreciated since tree growth still consumes CO2
I suppose I’m pointing it out to highlight the trade offs with any of these solutions.
What is unsaid is that we need to sequester CO2 for hundreds of years—often far beyond the lifespan of the trees. Trees are short term storage, and sometimes the storage is a lot shorter than popular imagination purports.
Biochar seems like a good option
It's a hugely underappreciated option. I'm not sure how accurate it is (or how legitimate the companies doing biochar carbon removal are), but cdr.fyi shows biochar as the top carbon sequestration method that's actually happening.
Trees have advantages that go beyond bureaucratic aspects of environmentalism.
I think that I shall never see a poem lovely as a tree. -- Joyce Kilmer
>Economics rules everything
Physics rules everything, once you start trying to run at scale.
The density of carbon per unit volume in solid materials of interest doesn't vary that much, whether you sink it in trees or in exotic materials like diamonds. That means you can calculate the volume of material required so sink a desired amount of atmospheric carbon.
If you want to have a measurable impact on the atmosphere, say dialing it back to 1980 CO2 levels, you're talking not about making a pile of stuff but about making a mountain range that's a mile high and hundreds of miles long.
Now figure out how many trucks you're going to need to move that much material from where your sequestering machine is to where your pile of stuff is.
Or if you want to dump that material in the ocean (which someone else will certainly object to), extend your calculation to figure out how many container trucks worth of material you need to dump into the ocean every hour to accomplish your atmospheric cleanup in whatever amount of time you choose (a decade? If it takes a century, that's not fast enough).
And finally think about surface to volume ratios. You're trying to sink it into a volume, but you can only get the gas into the volume through its surface, so the speed of your process is limited by surface area.
If you want to do it with trees, my personal spitball estimates are that you probably need to plant somewhere between the entire state of Connecticut and the entire state of Colorado to have the kind of impact one would want (there's more subtlety to tree calculations than one generally likes to admit, so feel free to come in with way higher numbers than I did).
Which brings us back to economics. If you have a well-managed forest of that size and scale, someone is eventually going to come along, maybe in 100 years, maybe in 500 years, and say "hey if we cut this down, we could burn the wood to heat our homes" and all that carbon goes back into the atmosphere, so you actually need to sink it into something that is energetically unfavorable for recovery, which means you also need to expand a huge amount of energy to sink the carbon into that energetically unfavorable state.
> you're talking not about making a pile of stuff but about making a mountain range that's a mile high and hundreds of miles long.
Just to put it into numbers, wikipedia has the total amount of CO2 on the global warming page, if we assume it's in a 2 g/l substance it totals to around 180 km^3.
But if you release the O2 and convert it into diamond, then by my highy-suspect back of the envelope calculations, it'd be a diamond that would fit into one square kilometer, 87 meters high. It would make quite the tourist attraction.
In the order of importance:
1. Even if we do magic and emit nothing, we still need to remove CO2 from the atmosphere or it will cook us over time, just longer.
2. We would need an enormous area for forests (which i great), which would mean a lot of intervention, like resettling people, demolishing and constructing new buildings, a lot of machinery time to move people to and from the new forests, a lot of planting and forest maintenance involved. And add he work to cut and bury resulting wood. If you would sum all the incidental emissions from this process it would rapidly become much less efficient (if at all).
Without either CO2 capture or a sun shade of some sort, the CO2 levels and temperature will only ever increase, just like now.
> it will cook us over time, just longer.
The largest sous-vide cooking pot ever...
I agree. Plants are not very efficient (1% or 2%) but they include packaging the CO2 in a stable form. You can store the grain or wood for long periods of times.
In this case, it looks like they get CO2 as a gas. It's cheaper because you don't have to use energy to undo the burning, but it's difficult to store for a long time.
(I'm not sure if someone tried to make a fake underground bog in abandoned mine. Just fill with wood and water to keep the oxygen low and make the wood decompose slowly.)
Take a look at "wood vault". 'Wood vaulting': A simple climate solution you’ve probably never heard of | Grist https://share.google/lS8xnMGEd1pMzlNg2 Economically not attractive but apparently very efficient in locking up CO2.
The problem with any scheme to capture and store carbon from the atmosphere is the incredible amount of carbon we've blown into the air in the last 150 years. Just look at the size of the machines we use to harvest coal. Essentially you'd need to have machines of similar size working for many decades to re-bury the carbon we extracted and burned. Who's gonna pay for that?
> stable form
Not really, forest fires happen and then a few hundred of years of sequestered CO2 gets released back in an instant.
Organic material with oxygen gas floating around is not stable.
Sequestering carbon into the ocean might be a better strategy. Not flammable and not subject to stupid capitalism effects around land prices.
Planting trees is not effective since it takes decades to capture the carbon, but the next years are crucial for determining long term climate developments.
There is no carbon capture technology on earth that can be rolled out at a scale over the next few years that can compete with planting trees. Especially not one that has just been invented in one university. Ash grows 90cm per year, that's all carbon. Scale that to millions and billions.
Without knowing much about the details of it, this might be interesting to evaluate as a potentially economically more attractive alternative to DAC in the supply chain of e-fuel production?
Just use lye to baking soda. You could in theory make an efficient roundtrip.
Anyway - CO2 in the atmosphere is here to stay. Much more "realistic" approach is to decarbonize the ocean and let the ocean absorb the atmospheric CO2.
how about trees? just a thought.
That's the first thing I thought when I read the title. Hey we have already efficient systems for eliminating CO2 from the athmosphere: trees!. The joke tells itself.
It seems like we have not yet done the full circle, but we are close.
I have an efficient method. It's called plants. Amazon is re-greening
The thing people don't think about with regards to CO2 capture is that you have to get the atmosphere in order to capture CO2 from it. You essentially have to suck the entire atmosphere into these carbon capture facilities.
Using something like this to capture carbon from an exhaust pipe might be viable, but scrubbing CO2 out of the atmosphere is not even remotely viable. There's just too much air out there.
Gasses diffuse through the air very quickly. Having a few high-volume extraction points would be enough long-term.
You can actually capture CO2 from sea water thereby reducing ocean acidification and improving its capability to continue as our planets biggest CO2 sink.
there's also lots of water to wash then.
The problem is the same, the relative concentration of oxygen in air is less than 0.05% (~450pars per million). In water much less.
Well here's the thing - there's quite a lot of water out there too.
How long and how many terawatts of power do you think it'll take to suck a significant fraction of the earth's seawater through a capture facility?
You're right, it's expensive and hard, so it's better to not do anything and... migrate all humanity onto space stations so we don't die with the earth, I guess is the alternative you're suggesting?
The earth doesn't die because CO2 levels increase. There have been multiple epoch with higher CO2 concentrations than we have now.
What are the use cases of CO2 appart for making my Coke fizz?
The main commercial use is enhanced oil recovery—shooting it into old wells to extract more oil (super ironic if captured from the air).
One application I think is neat is that it’s a pretty robust refrigerant in a heat pump application.
Synthetic food is a potentially big one.
Synthetic materials is another. For example carbon electrodes for batteries.
As I understand it, the main driver behind current carbon-capture tech is selling carbon credits.
Supercritical CO2 turbines: https://energy.wisc.edu/industry/technology-highlights/super...
On a much smaller scale I've been hoping for a small solar powered CO2 compressor to exist so I could use it for mosquito traps. The state of the art for those right now is burning propane for the CO2 combined with a scent emitter for the human smell to attract female mosquitos.
You can add hydrogen and make methane for those industries that can't easily electrify
It is used as a shielding gas in some welding processes (notably, MIG welding.)
Dry ice blasting
You can think of industrial CO2 use as basically the same as nitrogen but a little worse and several fucktons cheaper.
CO2 is fairly inert. This makes it useful. Welding steel is a typical example of something you can use CO2 to shield. There are many other examples in the chemicals industries of things like that where you want to do something at a "higher than natural on earth" temperature to make a reaction happen or happen faster but you don't want that reaction to happen with oxygen all around.
And on the other end of the temperature spectrum....dry ice.
Plant food.
Off the top of my head, CO2 can be used as a solvent for dry cleaning, it can extract THC from cannabis, and can also be used as a refrigerant.
You can combine it with H2 to produce synthetic fuels. Not ideal but could reduce fossil fuel use and hence new CO2 released.
Third ingredient missed out: lots of energy.
The reaction of 3 H2 + CO2 -> CH3OH + H2O is exergonic, so the H2 already brings all the energy needed.
This solves only part of the problem: it captures CO2 and can release it later. But you still need to figure out what to do with this CO2, how to turn it into something useful.
you can inject it into peridotites and let it mineralize. there is enough exposed peridotite outcrops in the world that we could inject all the co2 produced and store it there indefinitely. this process also produces elemental hydrogen.
Do you have any links on research on that? Serious question.
Yes.
For example:
https://www.pnas.org/doi/10.1073/pnas.0805794105
Peter Kelemen has written a lot of papers on this topic.
Here is a more recent paper that I wrote together with Peter and others currently in review:
https://eartharxiv.org/repository/view/9651/
This is more about the mechanics of how the rock breaks to allow fluids to move around.
And here is another paper currently in review that we coauthored about how we know there’s gas moving in the system and therefore hydrogen is being produced:
https://essopenarchive.org/users/543018/articles/1363688-eni...
Tbh I have no idea why we didn’t submit these to arXiv instead of these other preprint servers.
Thank you for this, it's very illuminating and awesome news.
I think it's worthy of its own submission as well (besides being very on topic on this subject here too).
Someone proposed to make giant beaches of malachite and let the sea break the rocks. Malachite has two -OH that can be replaced by a CO3= and so capture the CO2.
I can't find a good link now, but at least it's the only method I know where it's not obvious that requires a huge amount of energy that makes the whole process net negative.
A startup from Quebec is using an electrochemical process to produce potassium formate from CO2.
Electro Carbon https://www.electrocarbon.ca/en
https://sustainablebiz.ca/clear-the-runway-electro-carbon-be...
Their process for generating potassium formate is greener than standard methods. It does require electricity as an input but that can come from renewable, green sources.
Potassium formate is used in de-icing products, fertilizer, heat transfer fluids, drilling fluid, etc... so a useful, monetizeable output comes out of the process.
Disclosure - Know the founders personally. Wanted to shoutout their work. No financial ties to the company.Chemistry is not at all my expertise & I don't have details on their process beyond what's on the website.
I'm fine with keeping it inside something brick-shaped and chucking it down an abandoned mine from where it can be retrieved at a later time. It would definitely be a storage improvement over "the atmosphere and our lungs".
It can be used as an energy storage by compressing / releasing + powering a turbine. Good for storing excess wind + solar energy.
If it is reasonably energy efficient, this could be used to feed a methane processor, especially on Mars.
Stable storage would be limestone. To bring it down to pre-industrial levels it would mean that each person on earth would get a cube of 5 meters a side.
IDK, build houses out of limestone like we have been doing for ages.
Roads maybe?
The answer is obvious: create a cryptocurrency-based economy where countries and citizens are incentivized to pull CO2 out of the atmosphere and ship it into space in exchange for crypto.
/s
One of the subplots from the excellent Delta-V series by Daniel Suarez.