Why can’t we just sequester CO2 into plants we eat or forests?

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I saw a youtube video about how Japan burns materials that can’t easily be recycled to produce energy and captures the CO2 produced from the process. The CO2 is then sold to some local factories to produce various things like fire extinguishers, and some algae farms (I googled this and algae is used to produce food and oil).

I googled that at sea level, CO2 in the atmosphere is at 350 PPM, but certain plants thrive at 1500 PPM.

It got me thinking – why can’t we pump CO2 into indoor farms, plantations or forests to sequester more carbon?

Would that even work? Is the carbon just released into the air again once the plants are eaten or broken down?

In: Biology

23 Answers

Anonymous 0 Comments

One thing to think about when talking about CO2 and global warming is that carbon as a cycle, the same way water does.Remember in school ? Water from the ocean evaporates, forms clouds, it rains, it goes to a river, and back to the ocean.

Well, CO2 does the same thing. It’s in the air, it’s captured by living things (plants, algae, …), those things die (or get eaten), carbon goes into over living things… Untill it dies, rots and all, and you got carbon back into the air, eventually under the form of CO2.

So now the question is : if I burn a tree that has grown all alone (and thus procude CO2), do I partake in global warming ? Answer is : no. The carbon was in the cycle before, it’s still in the cycle after. (Similar question : if I home grow vegetable, but fertilize them, am I a problem ? The answer is yes)

The issue is : we take carbon that’s been out of this cycle for a long time, and stored beneath our feet as oil, gas or coal. We take that, burn it (it goes into the atmosphere), produce fertilizer with it (the carbon goes into bigger living things), and everything. We add carbon to the cycle : that’s the issue.

Now, planting a tree will capture some CO2 from the air. That’s right. This CO2 will be stored by the tree as wood and then, eventually along the line, will be released again as the tree is burned or it rots or gets eaten by something. Same goes with algae.

Because the carbon was never taken out of the cycle, it’s not a solution.

If you want to capture carbon, you have to store it so it’s not back into the cycle again. As diamond, for instance. That is conveniently the best way to store it : it’s the densest (meaning, more carbon in a given volume), and also it does not burn, melt, rot, not get eaten. I did the math once : if we want to take out the carbon we put into the atmosphere since the industrial revolution, and store it as diamond. If we want to do that in 30 years, not changing the rate at which we add carbon to the cycle as we do it (assuming free energy for our new machine that produces diamond from thin air), we will need to produce each yeah 4.3 cubic kilometer of diamond.That is a 1.7 km-long cube of pure diamond. Each year. The quantity is astronomical. Steel is, the metal we produce the most as a specie. And we produce 0.26 cubic kilometer a year of it. That is, 16 times less.(Those calculations were made in 2022. The cube got bigger since.)

So, sorry. But capturing carbon is not the solution.

Edit : Mandatory apology for the numerous mistakes, I’m not a native speaker

Second edit : It’s hard to realize what 4.3 cubic kilometer is. So here goes : it’s the same as having to cover Manathan with 70 meters of pure diamond, every year.

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