I was hoping that this proposal would be a uniquely unilateral one. If a single state or province in the USA or Canada committed to this plan (and if it worked as well as I optimistically propose, and provided enough nutrients) then they could singlehandedly put away enough carbon to actually solve the problem.

That's a bleak point of view and simply untrue. People have been shown to shift their view on consumption habits.

Social technology is the only tech that matters, as it's not just the carbon, it's also the plastic pollution, biosphere destruction, ocean acidification etc.

If we don't change the poeples want's, we can never have a stablish society.