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Efficient method to capture carbon dioxide from the atmosphere

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Re: Efficient method to capture carbon dioxide from the atmosphere

#191

Post by wcoenen »

progbits wrote: post #157
wcoenen wrote: post #126

Earlier quoted context omitted.

> 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.

See my sibling comment for meta-analysis that disagrees with you. Would love to see citation for those navy experiments.

Citation for a 2018 study with submarine-qualified sailors: https://pubmed.ncbi.nlm.nih.gov/29789085/

Re: Efficient method to capture carbon dioxide from the atmosphere

#192

Post by teknopaul »

ctoth wrote: post #129
ctoth wrote: post #124

Earlier quoted context omitted.

> 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 coordina…

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!

Covid proved this generalisation is not a truism.

USofA was probably the only place that actively resisted the global effort.

I think people do want a better world. Greed is not universal. Most countries that grow a middle class find most people prefer to stop work. I.e. there are not that many infinitely greedy humans. And they can be taxed.

Despite neocon economic theory, most people aren't selfish. And those that are, are often happily rewarded with a plaque in their honor or a medal.

Just look at the length Trump goes to for an award.

Re: Efficient method to capture carbon dioxide from the atmosphere

#193

Post by thinkcontext »

dylan604 wrote: post #49
roflmaostc wrote: post #4

Earlier quoted context omitted.

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...

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.

I think this loses the forest for the trees. That is, a single tree rotting isn't what matters its how long the ecosystem the tree is part of lasts. Consider a square kilometer of denuded land turned back into a forest. You can think of the forest as a temporary storage for carbon, its stored in the trees, soil, animals, insects, etc in that square kilometer. Individual trees may die but on average if the forest remains in good health there will be a number of tons of carbon kept out of the atmosphere.

Re: Efficient method to capture carbon dioxide from the atmosphere

#195

Post by thinkcontext »

adregan wrote: post #70
OsrsNeedsf2P wrote: post #35

Earlier quoted context omitted.

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.

Individual trees are short term storage which is why its important to create healthy ecosystems for them to live in. Turning denuded farmland back into a forest buffers carbon from the atmosphere for as long as the forest stands. It could stay there for centuries or return to the atmosphere if it gets bulldozed for a subdivision.

Re: Efficient method to capture carbon dioxide from the atmosphere

#196

Post by beachy »

jmward01 wrote: post #114

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 sequestrati…

Removing CO2 from the air is a pipe dream for several obvious reasons.

Firstly, it will always be more difficult and energy-intensive to extract CO2 than to just stop putting it into the atmosphere in the first place. Yet the world is nowhere near agreeing any meaningful framework on reducing emissions, and the party in power in the largest democracy in the world is in denial that a problem even exists.

But mainly, if there was an effective means of CO2 removal, who will be in charge of the dials, and who will set the targets?

Atmospheric CO2 is now 50% higher than when I was born. Will we go back to the levels as at the 60s, or perhaps the beginning of the industrial revolution? Obviously that is unfavorable to the frozen regions that are now thawing - like Russia (and Greenland), who benefit from climate change.

Re: Efficient method to capture carbon dioxide from the atmosphere

#197

Post by mnky9800n »

Gravityloss wrote: post #143
mnky9800n wrote: post #112

Earlier quoted context omitted.

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…

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).

I would be happy to have my papers on the front page of hacker news lol. So far it doesn’t happen.

Re: Efficient method to capture carbon dioxide from the atmosphere

#198

Post by loeg »

bilsbie wrote: post #175
condiment wrote: post #45

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…

Just to counter your extreme prediction, if co2 levels halve from here all life on earth goes extinct. https://www.researchgate.net/post/Minimum_necessary_concentr...

They aren't at risk of halving, though?

Re: Efficient method to capture carbon dioxide from the atmosphere

#199

Post by teknopaul »

teknopaul wrote: post #187
nine_k wrote: post #117

Earlier quoted context omitted.

Sequestering CO2 where it's highly concentrated, e.g. at power plants or cement factories exhausts, would be one way to emit less.

I think OPs point is this tech is good only if you sink it after. I. e. Collection is half the problem. Collecting it in a way it's cheap to get it back again is potentially just less than minus half the problem.

Did a bit of searching: fizzy drinks companies sometimes go and get stored CO2 to put in drinks or make it.

Any atmospheric extraction has a net positive compared to that.

Re: Efficient method to capture carbon dioxide from the atmosphere

#200

Post by loeg »

kzrdude wrote: post #153
leobg wrote: post #116

Earlier quoted context omitted.

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?

You could climb a mountain to test your hypothesis, keeping an eye on partial pressure of O2

We have a natural experiment. People in Denver aren't especially stupid.
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