Hilarious that nobody upvoted my post. I've been looking into the CO2 problem for more than 10 years & this seems like one of the most promising ideas... because it sounds possible to pull off.

Yes, I have the same question for Dr. Church. How does he plan to control their population? Maybe something like this:

https://news.mit.edu/2015/kill-switches-shut-down-engineered...

Something else will eat them. Even a human could.

Doesn't matter what eats them, after digestion, the CO2 is back in the atmosphere.

If you actually want to do this, you can't just leave them in the wild, you have to breed them in massive quantity and bury them. Same as growing a tree and burying it.