[cyphertruck]

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.

[roflmaostc]

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...

[manoDev]

Planting trees solves both the carbon capture and the emissions issue from different angles. Some examples are:

- With more wood available it’s more economical to use it as a building/manufacturing material over other emissive sources (concrete, steel, plastic)

- We can replant the same area multiple times

- Even if we plant crops for biofuels, it’s closer to carbon neutral than burning fossil anyway

Every move we can make towards planting (and managing) more of the surface of the Earth is an improvement, without waiting for miraculous new technology.

[cogman10]

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.

[Y-bar]

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.

[dylan604]

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.

[thinkcontext]

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.

[arkensaw]

using the wood for heating also releases the CO2. I do think planting trees is a good idea, but it's worth pointing out they can be a carbon source even after harvesting, depending on the usage.

On the other hand if the wood is used for construction or furniture it will not emit.

[loeg]

What do you think happens to harvested wood?

[dylan604]

why do you think it will only be used as fuel? it can also be used to build things with it

[loeg]

I didn't say fuel. It also rots when used as a building material.

[dylan604]

Then you’ve built poorly. That’s not the wood’s fault

[adregan]

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.

[OsrsNeedsf2P]

It's little appreciated since tree growth still consumes CO2

[adregan]

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.

[thinkcontext]

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.

[xnx]

Biochar seems like a good option

[gs17]

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.

[nephihaha]

Trees have advantages that go beyond bureaucratic aspects of environmentalism.

[fsckboy]

I think that I shall never see a poem lovely as a tree. -- Joyce Kilmer

[yodon]

>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.

[tzs]

If we took all the CO2 out of the atmosphere and converted the C into graphite and spread that uniformly over the top 10 subtropical deserts it would be around 2 cm deep.

This suggests a long term approach of building solar powered carbon capture plants in subtropical deserts, they capture it and convert to graphite, which is then spread out under the solar panels.

I once did the math on this, using the specs for currently available solar powered carbon capture, and it came out to something like if we used 100 years worth of the current production annual production of solar panels for this we could carbon capture at a rate that could drop the atmosphere from current levels of CO2 to pre-industrial levels in a few years even if we do not reduce emission rates.

So...not practical now, but might be feasible as a very long term project that over many decades builds out enough capacity to get things under control as long as we can keep everything from going to hell over that time.

[marcosdumay]

> 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 kg/l substance it totals to around 180 km^3.

[carbonguy]

To put it further into numbers -

1). Wikipedia does have a citation [1] saying 2,450 gigatonnes of CO2 have been emitted by human activity, of which 42% stayed in the atmosphere and 34% dissolved in the oceans, with the rest already sequestered by plant growth and land use. As we start to pull CO2 out of the atmosphere, it will begin to be emitted from the oceans as well; therefore, let's assume we have to recapture all excess atmospheric and oceanic CO2:

:: 2450x10^9 tonnes CO2 x .66 fraction to sequester ~= 1.6x10^12 tonnes CO2.

2) Let's convert the CO2 to something more stable for long-term storage: HDPE.

- Convert mass of CO2 to mass of carbon:

:: 1.6x10^12 tonnes CO2 x 12/44 mass fraction of C in CO2 ~= 4.4x10^11 tonnes C

- Convert mass C to mass HDPE; assume HDPE is effectively (CH2)n. Then:

:: 4.4x10^11 tonnes C x 14/12 mass fraction CH2 to C ~= 5.2x10^11 tonnes HDPE

3) That's a lot of plastic! How much volume? Wikipedia says HDPE is ~930-970 kg/m3; let's be conservative again and take the low figure:

:: 5.2x10^11 tonnes HDPE x 1.0/0.930 m3 per tonne HDPE ~= 5.5x10^11 m3 HDPE

4) Those are cubic meters; how about cubic kilometers?

:: 5.5x10^11 m3 x 1.0/1.0x10^9 km3 per m3 ~= 5.5x10^2 km3

In other words, if you turned all the [excess potentially climate-change impacting] CO2 that humanity has emitted since 1850 into plastic (a process that would certainly emit a large additional CO2 fraction given the industrial buildout required) then we'd end up with about 550 cubic kilometers of the stuff. Coincidentally, that's about the volume of Mount Everest according to an intermediate calculation in [2].

So, a mountain of carbon: more than a pile but less than a mountain range.

[1] https://en.wikipedia.org/wiki/Carbon_dioxide_in_the_atmosphe...

[2] https://www.quora.com/What-would-the-estimated-weight-of-Mou...

[three14]

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.

[marcosdumay]

My number is without the O2.

It's a literal mountain chain of plastic. We do have uses for it, but it's a lot.

[sokoloff]

If we pull this off, I would not expect people 500 years from now to undo it.

[Yizahi]

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.

[jacquesm]

> it will cook us over time, just longer.

The largest sous-vide cooking pot ever...

[gus_massa]

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.)

[cjbenedikt]

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.

[adrianN]

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?

[mr_toad]

There’s no getting around it. If we reduce CO2 emissions to zero it’s either plants or carbon capture, and one way or another the planet will have to do something with all that carbon.

Last time it took plants millions of years, and that was before things started eating wood. I’m pretty sure that we’ll have to have a hand in the process if we want to reduce CO2 levels in timespans shorter than geological.

[adrianN]

I agree that we’ll actively have to do something if we want to reduce carbon levels. I’m not convinced that we’ll want to reduce carbon levels badly enough to spent all that money. It’s very hard to convince voters that they’ll have to spent lots of taxes for a project that sees payoff in two or three generations at the earliest.

[dheera]

> 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.

[lefra]

The ocean has already absorbed 30% of the CO2 humanity has emitted. It causes issues: ocean acidity rises, which reduces plankton ability to grow. Plankton being the base of the ocean food chain, all ocean life gets impacted.

You'd need to find a way to sequester carbon without it leaching in the water.

https://marine.copernicus.eu/ocean-climate-portal/ocean-carb...

[dheera]

Random idea: What if we just sequestered it into elemental carbon pellets and let it sink to the bottom of the ocean? It should not react with the water.

[gus_massa]

One idea is to charcoal the wood, it makes it harder to decompose and is similar to pure carbon. I'm not sure if it's better to send it to the bottom of the ocean or just to a big hole on land.

[dheera]

The big hole on land could be dangerous if a fire ever gets there. I suppose, maybe a big hole in the middle of northern Canada might be fine

[S3verin]

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.

[adammarples]

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.