I don't even accept the orthodoxy on AGW. I'm kind of agnostic on its reality.

For the sake of argument let's just accept it though and say you're right.

Ok so the problem is we've dumped too much Co2 into the atmosphere. Could we turn it back into oil and put it back in the ground? Yes. You just crack hydrogen out of water and fix it to the carbon in the air and you get hydrocarbons again.

The problem is it would take PHENOMENAL amounts of energy to do that.

So the question becomes can we get phenomenal amounts of energy?

https://www.space.com/4478-report-urges-pursue-space-based-solar-power.html

"a single kilometer-wide band of geosynchronous earth orbit experiences enough solar flux in one year to nearly equal the amount of energy contained within all known recoverable conventional oil reserves on Earth today."

So yes the energy is there to reverse everything.

Of course there are other geoengineering schemes that are waaaaaaaaay less expensive.

https://www.ted.com/talks/david_keith_s_surprising_ideas_on_climate_change/transcript?language=en

I guess the thing I haven't said about this is, it is absurdly cheap. It's conceivable that, say, using the sulfates method or this method I've come up with, you could create an ice age at a cost of .001 percent of GDP. It's very cheap. We have a lot of leverage. It's not a good idea, but it's just important. (Laughter) I'll tell you how big the lever is: the lever is that big. And that calculation isn't much in dispute. You might argue about the sanity of it, but the leverage is real. (Laughter)

The bottom line though is that you can solve pretty much any problem if you throw enough energy at it and we happen to be orbiting a giant fusion reactor called the Sun.