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
> Is the carbon just released into the air again once the plants are eaten or broken down
yes
This is an idea (“one trillion trees”), the question is can it be done on the scale needed?
Much of the Northern Hemisphere forest land that was cut down now has other uses.
Yes! You can grow plants. They’d have to be new plants that weren’t there before,
There is also “carbon capture” technology where carbon from the atmosphere is collected and stored (carbon sequestration).
People are researching these things.
For this to be effective, it would have to completely offset all the carbon which is put into the air each year.
At the moment, they aren’t anywhere near the scale which is needed. It’s like trying to empty a lake with a coffee mug while a river is also flowing into it. But maybe there will be a breakthrough someday.
The amount of carbon in the world we screwed up on here is massive. The ultimate goal is to bring that atmosphere CO2 density down from ~~350~~ 420 PPM to around 300 PPM, probably even lower. But that’s for the whole atmosphere across the entire planet and represents literal billions of tonnes of carbon.
Such small plans to use carbon for something useful are nice, but don’t solve the global problem. It just very slightly slows down the rate at which CO2 is added to the atmosphere. For example, all the cars in the world burning fuels are still going. A couple of factories NOT blowing their CO2 into the air and using it for something else is a step in the right direction, but it’s a hell of a long way to go.
Trees aren’t a great sequester strategy. They grow old, die, burn down in forest fires, and regrow. That’s a carbon cycle of a few hundred years. What we need to make up for is the incredibly number of tonnes of oil drilled out from the ground and burned over the last century or so. Trees aren’t going to make up the difference… unless we could turbo grow the trees, cut them down, and then bury them somewhere, like where all that oil once was. But the scale of the project is still crazy huge if we want to have trees grown at the same rate we consume oil… or, higher really to get that CO2 level to start decreasing.
This is a very common thing in greenhouses. Burning things creates CO2, water and heat, all of which improves the growth of plants. Usually what is being burned is natural gas though as this burns cleanly. You can also burn other things but it tends to create sot and toxins which needs to be filtered out.
The issue we come back to all the time is how to capture carbon. This is relatively easy in a chemical plant which already produce almost pure CO2 in a part of their process. Currently almost all CO2 sold in the world comes from ammonia production. There are projects working on CO2 extraction from cement plants, another chemical process which produce very clean CO2. But so far none are commercially viable.
Capturing CO2 from dirty sources like the exhaust gasses of incinerators and power plants is a much harder problem. The project you are talking about in Japan is very innovative but is costing the government a lot of money. There are other projects working on capturing CO2 from the atmosphere. This is also tricky because the atmosphere does not have much CO2 so you need to process a lot of air to get just a bit of CO2. But this does actually have some merits when connected to a greenhouse as the short transportation distance gives them an economic advantage. So we might see CO2 scrubbers connected to greenhouses in the not so distant future to replace their natural gas burners.
The important question is the one at the end of your comments. We can increase the number of plants being grown, but if you really wanted to “fix” the CO2 out of the atmosphere in large quantities, you’d also have to worry about what happens to those plants at the end of their lifespans, whether that be because they’re eaten, or die and rot, or what have you.
The carbon being released into the atmosphere through fossil fuel use comes from plant and other biological matter that was trapped in the ground over millions of years, eventually decomposing into oil, gas, coal, etc.
> Would that even work? Is the carbon just released into the air again once the plants are eaten or broken down?
This is one issue. Plants are a short term Carbon sink.
The other problem is that most of the Carbon we’ve released into the atmosphere was trapped underground. We’d have to replant all the plant biomass we’ve deforested on the surface **and** enough to compensate for everything we’ve taken out of the ground.
Interesting fact: The Biosphere 2 experiment was created as a prototype mars colony and remains the largest fully sealed lab space ever created. The team was sealed inside for a year and early on their CO2 levels began skyrocketing (unknown at the time, there were still chemical processes releasing CO2 from the fresh cement still curing).
One of the ways they tried to offset this was by doing exactly what your suggest- growing fast growing plants, cutting them, then just setting them side.
https://en.m.wikipedia.org/wiki/Biosphere_2
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.
Cellular respiration generally looks like this
C6H12O6 + 6O2 -> 6CO2 + 6H2O
So yes, trying to sequester CO2 by putting the carbon into plants that we eat would just result in us breathing that carbon right back out into the environment
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