I agree with everything you said except for your last paragraph. Scientifically speaking, it is not to late. Politically it is, but politics can and have swung wildly. Our best bet is the younger generation shows up to the polls and votes in green candidates. My local area has had some good success with this at least.

As for the geoengineering, I can see that being the unfortunate case. I'm concerned it's going to be a far dumber and dangerous version of it though, like intentionally nuking a remote islands a couple times to start a mild nuclear winter.