Any question answered...

I see. I think I disagree on most points, unless I'm still misunderstanding you.

Once we get past the "anthropogenic climate change will change the way we live for the worse" step, which is a huge hurdle but let's take it as read for a moment,

Not sure if climate change denier or future-technology-will-save-the-world believer?

In any case, I'm not a scientist. I'm barely a social scientist. However, I do have faith in the consensus of the people who know this shit better than me.

the reaction is dominated by people whose response is to destroy the present economy (by autocratic action, since that's the kind which makes politicians feel big) in the hope that doing so will arrest the climate change.
It's really not. At least, not since 2006 and the Stern Review. There are of course going to be people like those you're describing, but I would not for a second say the debate is dominated by those people. At least, not in academic or political arenas.

Many people oppose things like cap and trade, but not because it's an economic solution, but because they think it's an insufficient solution.

This is usually economically illiterate, since it is paying now for a putative benefit in several decades' time, and the politicians making this prescription usually fail to apply appropriate discounts. Also, it's not even clear what the benefit is; it seems to be that a changed climate will only support an economy of say 50% of current size, but if we cut the size of the economy by 50% we can prevent the climate change. Either way, we end up with a smaller economy, but under their prescription we get it now rather than later.
You're right that discounts are difficult. And there has been discussion on the actual rate used in 2006. But this is something that experts are, and will continue to, struggle with. It is not, however, pulled out of the air.

If your boss came to you and said
"Today, I'm paying you £10/h, but if I keep doing that, in 10 years' time I'll only be able to afford to pay you £10/h. However, if I cut your pay now to £5/h, in ten years' time I'll be able to give you a raise to £10/h"
you'd tell him to fuck off.
It's more like this: your boss comes up to you and says I can continue to pay you £10/h, but if I keep doing that, I predict that in 10 years I will only be able to pay you £5/h, and the worse case scenario is that you won't have a job. Or, I can pay you £6/h now in an ten years I will continue to pay you £6/h but the likelihood of you having a job is much higher.

This is because, first, a cost-benefit analysis shows that it's not an equal pay off. It is economically beneficial to take aggressive action. That is, initial costs equal long term relative gains. Second, a simple cost-benefit analysis ignores other factors, of which I mentioned one (the possibility of catastrophic failure).

There are also ethical issues with the economic approach. Such as the monetary value of intangibles (human life, the extinction of species, the asymmetry of climate change).

Anyway! Like I said, I'm not an expert.