A thought that just came to mind following the Long report from CA, below.
Why tie climate policy schemes only to carbon, and thus internalize concerns about attribution, as well as prolong the denier-warmer debate?
Why can't we tie a Coasian climate policy instead to carbon volume via the actual climate change itself, using some reasonable central indicator such as global AAT increase? It's true that we have imperfect measures of the impact of each unit of carbon on AAT, but the models that approximate this, GCMs and the Lean and Rind multiple regression, and so on, give us workable correlation coefficients. If we just picked one, however arbitrary, we would abstract away from this issue, while abstracting towards actual solutions.
One option that satisfies this concept would be to make the fee per unit of fossil energy use in one time period a function of the AAT change during the previous period, after correcting for ENSO, the solar cycle, and volcanic aerosols.
That way investors would have to strategize using more complex thoughts about the mix of carbon and carbon free technologies, going forward.
Let the Koch brothers and their ilk bet against climate change if they wish. But make the consequences of such a bet direct and natural.
Deniers shouldn't complain about such a policy, since they believe that climate change is not a result of all that carbon. If you tie carbon fees to both carbon and ATT, if the deniers are right, the fee would be minimal. Which is just what they believe should happen. If they're wrong, they get left holding a whole bunch of worthless investments.
We could call it the "Put your money where your mouth is" climate policy.
Whereas right now, the cheapest route for the Kochs, et al, is to fund the denial movement!
I don't have time to take this idea very far myself, but someone else in the mitigation business might.
So I'm just putting it out there.