I will be writing tons on this topic in the coming weeks, but my immediate reaction to the IPCC AR5 Working Group II report that came out Monday is now up at IER. An excerpt:
Now the reader should understand the hole into which the climate alarmists have dug themselves. They can’t have the IPCC running around telling people that the best projection of climate change damage will be “0.2% to 2.0%” of global income, either by mid-century (at worst) or possibly not until 2090, when they’ve spent a few years reassuring Americans that their preferred anti-carbon policies will cost 2% of income by 2050. Even using their own numbers, these policies clearly fail a standard cost/benefit test. (It obviously doesn’t make sense to spend $2,000 in the year 2050 to prevent a bad outcome that will probably cost you $1,000 in the year 2090, and the same logic applies to percentages of income.) The cost/benefit comparisons get much worse when you consider that even in their own computer simulations, the various carbon tax and cap-and-trade proposals will only reduce (not eliminate) the total damages from climate change; thus the economic costs of these policies must be compared to the potential benefits of avoiding only some fraction of the projected damages of climate change.
As I said, there are all sorts of other issues to discuss, such as the framing of anti-carbon policies as insurance. But I thought it important to underscore, on this first pass, what the big-picture middle-of-the-road numbers say. This is not at ALL what you would think, if you just listened to the conventional discussion.