CAGW and Consensus
What about the low end? At 3°C, the welfare impact is a reduction of 10%. The IPCC high emissions scenario, RCP8.5, which gets us to that temperature sometime in the second half of the century, assumes continued economic growth. If so, the 10% reduction in welfare due to AGW will be combined with an increase several times that large.
My previous post discussed an article in the Journal of the National Academy of Sciences which criticized the IPCC models and concluded that warming due to AGW had been reasonably stable for the past century at a little less than one degree/century. If that continues, by 2100 global temperature will be less than two degrees above its preindustrial level. On Tol's estimate, we will be better off than if there had been no AGW, worse off than if AGW had been a little slower.
If, on the other hand, we accept RCP8.5, when we reach the 3° mark we will be worse off than if warming had not occurred, better off than we are now—even if we take the low end of Tol's predicted range of effects.
Which I think is an adequate response to people who tell me that to deny catastrophic effects of warming is to ignore the scientific consensus.