X is bad? Fine. Accurately prove how they are bad, in a way that is relatively easy to proof in a repeatable way. Gimme alternatives that are viable (ie can be realistically implemented in a reasonable manner), that are economic (preferably cheaper, but no more than 5-10% more expensive) that are effective (preferably better, but no more than 5-10% less effiicient).
While I'm in agreement with this view, I'm also aware of how much messier the AGW situation is than the CFC situation was. Anything beyond "anthropogenic gases are probably adding about 0.2% (1.6 W/m**2) to the Earth's heat budget at the surface" is extremely model dependent, and models are just not that good at predicting the detailed response of such a complex system.
I am a computational physicist, and it is very clear after digging in to climate models a bit that climate models are not written by computational physicists, who typically have dealt with much simpler systems in much better controlled (and experimentally accessible) situations, which gives us a very healthy awareness of how inadequate our simulations are at capturing anything but the gross features of reality.
If a computational model of a radiation detector comes within 10% of reality you're generally doing pretty well, and radiation detectors of various kinds are about as simple as you can get in terms of physics.
So anyone who claims that climate models are adequate or even particularly useful as guides to policy response is likely not tightly coupled to reality. We don't really know what areas are likely to be affected by what kind of events. Even apparently simple things like an increase in hurricane force winds, or possibly an increase in the number of hurricanes, are hotly debated. No one, to the best of my knowledge, predicted ocean acidification as a likely outcome of increasing levels of atmospheric CO2, but this is likely going to be one of the more significant impacts. And so on.
As such, it behooves us to pursue a number of policies that won't address any specific threat, but which will a) reduce human greenhouse gas emissions and b) increase our ability to respond the climate-driven humanitarian disasters. In the former category would be nuclear power development and other green power sources, and in the latter things like increased funds put aside for international relief via existing organizations.
These positive actions have zero political support, however: people who are beating the drums regarding AGW policy are almost uniformly putting it in terms of controls and limits and restrictions on other people, which we know from far too much history never ends well, and certainly never solves the problem it was supposedly intended to address.