I know it sounds far-fetched, but if someone develops a technology that can rapidly grow a wood-like material out of atmospheric carbon in such a way that entire buildings can be grown in single digit years, we could start seeing countries fighting over who is using too much CO2 and consuming too little
I've been meaning to try and do an estimate related to this. Just how much CO2 could be pulled out of the air by _extensive_ farming of fast growing trees. We could find ways to use as much of the wood as possible (construction materials, etc.), and just sink the remaining wood in cold water where the carbon would stay locked away for 100+ years.
Then again, if my numbers are right, if humankind dedicated <1% of land used worldwide for food to growing trees and locking away the cellulose, we would cancel out worldwide CO2 emissions. Since most of that land is used as pasture, there is more than enough play to keep the world fed, and I could see up to 10% being tasked to this purpose , which seems doable in an emergency.
Have you accounted for moving the trees from where they grow to where they can be used? (E.g., milling, planing, curing.) That will take energy that likely offsets some of the benefits.
Likewise, moving the lumber or finished goods to consumers will also require some energy that might offset the carbon removed.
I initially thought it didn't look good when looking at the amount absorbed yearly per tree, but then was surprised by some estimates on how many trees you can fit per unit area. A more accurate estimate needs to be done though, different numbers I found put the final range at about an order of magnitude.
Also, most farming and stable forests are mostly carbon neutral. This would require continual seeding, harvesting and sequestration of the cellulose. Maybe it will be a good thing though that cellulose+lignins are so hard to breakdown.
