Just to be clear, if humans gave up on THIS form of geoengineering it’d suck. Not necessarily all forms would have this kind of problem.
E.g., anything you do to remove CO2 from the atmosphere is pretty much guaranteed to be safe.* If going from 399 ppm to 400 ppm didn’t send you over some sort of catastrophic tipping point, then neither will going from 400 back down to 399, or getting complacent and letting it rise back up to 400 once again.
* i.e., “safe” in terms of these kinds of effects. No comment on how difficult it would be to do such a thing in a way that was not itself destructive to the environment.
