The news media is in high gear in anticipation of the IPCC summary for policymakers that will be issued tomorrow. I think I will have to go into hiding for a couple days or my blood pressure will go through the roof. Leave it to the French to darken the Eiffel Tower to reflect the seriousness of the event.
So about 12 years ago, in my Environmental Economics course at Tuck, I had a "skeptic" in to class to discuss climate change -- Robert Balling. Now in the interest of balance, I also invited to the class Donella Meadows (Limits to Growth) and she did attend. It was one of my all time favorite class sessions. The students who were there probably still do not realize how lucky they were to see Balling and Meadows square off -- and agree on much of the science, but not on the policy implications!
So it sounds like one of the news bytes will be that mankind is "very likely" to be a cause of some (how much?) of the warming we have observed. Twelve years ago, Balling, a skeptic, would have agreed to that. I remember him going through the data, with a focus on moderate warming, especially at night and in winters, and more rainfall generally. That, he said is global warming. The question then, and now, is what we should do about it.
So the IPCC summary will try to make a big deal out of the "very likely" language, and all the media will try to use it to say that all skeptics have been discredited. I don't know of any skeptics who deny the theory of climate change (i.e., the causal relationship to CO2) or indeed any who would not agree that some of the warming we have observed in the last 100 years is "very likely" due to human influence.
That is just not the point.
It will be interesting to see the spin if, as I expect, the expected temperature increase and expected sea level increases both fall from previous expected values. How do you spin that into more of a crisis?