Doing nothing but solar radiation management has serious downsides: it does nothing for ocean acidification, and if you ever stop pumping out that sulfur dioxide or whatever, all that pent-up warming hits you at once. I see it as a temporary emergency measure, to head off heat-driven feedback effects.
This right here sums up about 97% of the entire issue. People look at the scale of problem, figure they can't make "a real difference" and use that as justification for continuing on with business as usual. It boils down to "The pain and nuisance of me personally taking fewer airplane trips, walking more or eating less meat (or whatever) far outweighs in my mind the benefit to The World of me inconveniencing myself. So Why Bother?"
And, conveniently, it's an argument that frames itself in a way that is nigh impossible to argue with.
Taxes can always be repealed, but I’d like to see us start giving a shit before we assume this won’t work, because whatever we are doing now doesn’t work!
> We need to adapt. To limit the damage, and fix things.
The first contributes to the second.
The implied corollary is of course that if we slow down emissions global warming will stop. And it won't. It will slow down, but not stop. Not even if we get net emissions to zero.
No we don't. Global warming is a self-reinforcing effect. So there's no point to slowing down emissions. No point at all. Even if you get it to zero, the resulting concentrations will still accelerate into the right. Even if you get it negative at the same rate we're producing it today (which would eliminate all human co2 contributions EVER in ~60 years) would do nothing but delay.
So why bother ? This avenue is closed, and useless.
We glued a grenade to our hand, and pulled the pin. Messing around trying to insert the pin back in provides nothing but comic relief. We need to adapt. To limit the damage, and fix things.
As you say, only direct geoengineering can work. On the plus side: doesn't require global cooperation. On the downside: that'll make someone clearly directly responsible for the (MUCH worse) effects global cooling will have, especially locally ... so it's extremely incompatible with how current green parties think and "influence policy".
Whereas the current "complain and do nothing but token efforts" is very good at getting constant attention, votes and money. But only if the problem keeps getting worse.
So just like everyone they accuse, green and leftist parties themselves are dependent on global warming happening and getting worse. Maybe that, too, is a reason why we have nothing but token efforts. Also, they would have to admit that "mother nature"/gaia is definitely NOT going to save our ass, even if we stop polluting.
Additionally, Gaia, so to speak, has already decided to inflict global warming on us, as a punishment or just because, take your pick, effectively for what humanity did at the end of the 19th (not 20th) century. So we need to inflict further damage on the ecosystem artificially controlling the temperature to prevent worse. But that'll futher destroy habitats, and on a much larger scale than what we've seen so far.
Not eating meat, capturing co2, lab-grown meat, even nuclear power ... just can't work. Only geoengineering can work.