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Comment by Klapaucius | Hacker News Reader

Sequestring CO2 is a huge scale problem, and all solutions have significant flaws. Forests require vasts amounts of land, and storage is only assured as long as nobody decides to chop down the forest for other more pressing purposes (looking at you, Brazil). Storing CO2 in oceans (either in the form of "ocean fertilization" or by directly dissolving CO2 in seawater) could have huge and unknown consequences for marine ecosystems. Other solutions such as biochar and enhanced weathering of minerals have limited scalability.

As I see it, Geological CO2 storage (CCS) may be the only large-scale practical way going forward, despite all the bad rap it gets due to its historical association with the fossile fuel industry. After all, the excess C in the system came from the ground, and the ground may be the only place able to re-absorb it without significant environmental consequences.

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> storage is only assured as long as nobody decides to chop down the forest for other more pressing purposes

Yes and no; if we're talking about logging for lumber then it's really a question of efficiency. Logging in optimal ways helps you minimize carbon release and maximize wood production long-term. If most of the wood is used in construction the carbon remains captured so long as the building stands or the timber is re-used or eventually buried, i.e. scrap wood from a tear-down or remodel isn't burned or left near enough to the surface to rot.

Setting aside land for logging this way has the benefit of using economic activity to our advantage. There are obviously limits but there is no one magic solution to climate change.

"storage is only assured as long as nobody decides to chop down the forest"

In 2020 "the Lionshead Fire [...] have almost completely engulfed the largest forest dedicated to sequestering carbon dioxide in the state [of Oregon]". Turns out that Nature may also decide to destroy a forest. Biomass comes and goes. As you stated, geostorage is the only solution that makes sense from a first principles perspective.

https://grist.org/climate/this-oregon-forest-was-supposed-to...

Wildfire is a natural part of many forest ecosystems, so it is definitely worth factoring that into plans for CO2 capture. Perhaps we can lean more heavily on high carbon capturing forests for construction and furniture again.

>despite all the bad rap it gets due to its historical association with the fossile fuel industry.

It's not really historical as in far in the past. The relatively recent bill pushed by Trump that gives massive tax credits for CO2 sequestration were a veiled subsidy(or whatever you wish to call it) towards extracting more oil with enhanced oil recovery.

Even if proposed for vicarious motives, the technology as such may still be the right way to go.

From an environmental perspective, CO2 sequestration for EOR (enhanced oil recovery) makes little sense, other than reducing the carbon footprint of production a bit, demonstrating the storage principle and further developing key technology.

What makes more sense is to use geological storage for CO2 captured from industrial processes other than power generation - production of cement, steel and chemicals, in other words processes that would release large amounts of CO2 even if switching 100% to renewable energy.

Also, we need some place to store all that CO2 that purportedly would be captured using DAC (direct air capture) in the future.

I feel like artificial DAC will be a pipedream. Especially when we can't even stop ourselves from emitting now which is ridiculously much easier I don't see us capturing co2 at 412ppm on an almost unfathomable scale.

> Forests require vasts amounts of land,

When people say this they typically mean the land is no longer usable for another purpose. I don't think this is the case with 'forests,' let alone adding more trees to empty spaces in currently populated areas.

> may be the only large-scale practical way going forward

Why must it be "large-scale?" "We could plant trees, in addition to implementing many other common sense measures and improvements collectively." "Yes, but is it web-scale?"

The only reason to do this is to create a large for profit industry driven solely by monopoly granting regulatory bodies as opposed to many individual markets driven by reasonable and non-discriminatory laws and enforcement.

Is it possible to vent the CO2 into space?

The earth is constantly 'venting' gas to space. This is known as atmospheric escape. https://en.wikipedia.org/wiki/Atmospheric_escape

The earth is currently losing 3kg/s hydrogen and 50g/s of helium because that's what is in the upper atmosphere where a molecule can gain sufficient velocity to escape the orbit.

The issue with CO2 is that it is a heavier gas and so takes more energy to escape and is also more likely to fall. Left on its own over a sufficiently long time period, you'll end up with an atmosphere that is mostly rarefied carbon dioxide (see Mars).

Ejecting CO2 from ground level to the upper atmosphere and beyond in the quantities that are talked about when dealing with carbon sequestration (tons - not kilograms or grams) would be very energy intensive and using current technologies (we don't have surplus non-carbon based energy) would mean that we are adding to the total amount of carbon instead of reducing it.

(since the 3kg/s and tons was bothering me...)

3kg/s is 95kt/year. The United States emits about 4,900,000kt/year of CO2.

Just wanted to get those rates on the same scale.

Short answer is no. CO2 is sitting at about 400ppm( parts per million(. So take a million things, say golf balls, and paint 400 of them red. The rest white. Put them in a container, then search for the red balls. The goal is to get at least ~150 to 200 before you have to look at the next batch. There's not really a quick way to do that.

Green house gas is such a hard problem because it's a dispersed problem. This is where we need to stop removing plant life from the earth, and start seriously considering a little bit of CRISPR to tweak plants to grow fast and absorb as much co2 as possible. It'd also be great if we started iron seeding the southern ocean to kick that ecosystem into gear as we really need evertying to start sequestering carbon.

On that gene editing...

(background on C3 vs C4 plants) https://ripe.illinois.edu/blog/difference-between-c3-and-c4-...

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3075750/

https://www.frontiersin.org/articles/10.3389/fpls.2021.71539...

https://innovativegenomics.org/projects/improving-photosynth...

https://www.nationalgeographic.com/environment/article/can-w...

"start seriously considering a little bit of CRISPR"

We should consider taking a collective pause to think things through. Our extensive technology use is pushing ecosystems out of balance at planet scale. Perhaps the solution is NOT more technology, with inherently unknown longterm consequences.

It actually is more technology. Our extensive techonology use it not pushing ecosystems out of balance. It's our massive land use changes and requirements for land that are.

Unless we quickly get much better at this at some point not long from now we are going to end up in a situation where such reckless solutions might be the only options we have left.

I don't think this is a great explanation. I could build a machine that would get rid of 200 red balls (out of a million) in 30 minutes. It's a linearly parallelizable problem, so with enough machines, I could make it go as quickly as you'd like.

Maybe we could use a massively scalable set of machinery that uses sunlight to produce energy and sequester carbon. Seems like the machinery could be nature inspired… or maybe just natural. Plants could just be the answer we are all reaching for here.

You want to find an answer? I believe the solution (if any is to be found) is going to be a combination of dozens of different actions. So grow plants and build machines and dump iron in the ocean and cut down on oil use and move people away from coasts around the equator and come up with some type of global basic income and build nuclear reactors and windmills and geothermal and move to electric cars and redesign cities to reduce the need for cars and come up with a plan for colonizing the stars and embrace GMOs to reduced the impact of agriculture and encourage people to eat less meat and so on.

One of my favorite channels on YouTube is Kurzgesagt and they recently (looking at date, well, last year - still recent in the scale of things) had a video on global warming - Can YOU Fix Climate Change? https://youtu.be/yiw6_JakZFc

There's also

Do we Need Nuclear Energy to Stop Climate Change? - https://youtu.be/EhAemz1v7dQ

Is It Too Late To Stop Climate Change? Well, it's Complicated. - https://youtu.be/wbR-5mHI6bo

Don't know, seems like a good explanation. We have a number of machines that can take CO2 out, the "enough machines" is the problem.

- they either require space (forests or whatever)

- are hard to produce in sufficient numbers (materials, production capabilities)

- are expensive to run (like energy input, maintenance), in particular don't generate new red balls while removing them.

- disposal cost (where the machine becomes the carbon, like trees, cutting them down and doing something with that)

Once we got it out, on a "pile of carbon", the problem becomes much easier.

As you are doing this, you need energy. You either need it from a source that doesn't generate red balls and thus is sufficiently dense energy to be useful, or leave the density of red balls after you've identified 200 to be remove lower than it was before you started.

Everything is possible.

Feasible is a different issue.

It is hugely expensive (give CO2 escape velocity) and wasteful (CO2 is a valuable substance, containing 2 important elements).

Carbon is necessary for all life.

It might be in the wrong place (atmosphere) but we definitely want it on the earth, not in outer space.

No.

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