I'm not a fan of geoengineering, which I see as "screwing around" because we don't know nearly enough to predict its effects. Nonetheless, we may well reach a point where it cannot make things worse, and that point just became even more likely.
BTW I am actually cautiously optimistic about the GHG reduction piece. We’re way past where we should be at this stage, but rapid decarbonization now looks like it will be at least technically possible. Most global emissions are in China and Asia, and China is actually deploying the technology we need to eliminate those emissions. The US shouldn’t be screwing around the way it is, but I’m hopeful that what’s happening with renewable technology costs in Asia will eventually be more meaningful than any short term political interference that’s limited to the US. (This is very much a lemonade-out-of-lemons opinion, but the alternative is to be very depressed.)