Steve doesn't care for policy discussions, so here is what I wanted to post to this comment by Eschenbach.
Good Lord! Even your straw men have straw men!
My claim was that there are "people who understand the climate system much better than most of the regulars here". Then you proceeded to argue against the proposition that there are "people who understand the climate system". Well, not exactly argue.
However, if you believe that there is insufficient knowledge to project the evolution of the system for a century even crudely, I presume you would be very wary of changing its bulk radiative properties, right? If I were as contemptuous about climate science as you I'd be far more terrified of any global changes in concentration of radiatively active components than I am now.
There are several ways to constrain the global sensitivity of temperature to CO2 concentration, of which millenial reconstructions is the weakest, for reasons better known to readers of this group than to myself. There are other ways to estimate that key quantity. So reduced to that one quantity, we have a pretty good handle on it. It's too big to be comfortable postponing decarbonizing the economy until we run out of carbon.
But if you don't believe that, you have no way of knowing whether we are very close to utter catastrophe. So you should support cutting back on carbon emissions in the most drastic urgency.