I don’t buy the “runaway” argument. First, it requires mysterious forces: CO2 levels alone cannot produce the temperature increase that the AGW camp wants us to worry about. They admit this. So they point to the feedback that they say will come from CO2 increase, presumably causing water vapor to act as a greenhouse gas and boil us all. Why would water vapor suddenly acquire those properties? Water vapor’s behavior –under all sorts of physical and chemical regimes– is pretty well characterized. And we all see everyday what it does: the sun heats things up, the air absorbs more moisture, the hot wet air tends to rise, expand and cool, and lo, we get rain and snow. Every single time. That is a natural and compelling case of *negative* feedback, where the heat (obedient to the laws of thermodynamics) wants to head for someplace cooler, and the air and water “transport” it. Why would a modest (and precedented) increase in a trace gas, possessing only a tiny fraction of the thermal mass of the water vapor in the atmosphere, suddenly dictate changes in the water vapor cycle? That have never been seen before? That defy the laws of physics?

Second: if they want to posit mysterious processes, fine. But the burden of proof is on them. Unless they can supply a plausible explanation and connect the dots for a cause-and-effect demonstration, they lose. In particular, they need to show that “but for” their process, the current model of the climate is inadequate. Last time I looked, my model of the climate is working just fine. It just doesn’t happen to produce the runaway catastrophes they want to sell me. Epic fail.

Sorry for all the question marks, but they are what skeptics use.