Nick, on Aug 29 2005, 10:48 PM, said:
That's not really correct: increasing the (thermal) energy of the climate is going to increase the severity of catastrophic (in the technical sense) shifts in weather, including such phenomena as hurricanes. [Also, paradoxically, cold spells.] The mathematics of catastrophe theory aren't completely worked out, of course, but they're solid enough, and the models uniform enough in that conclusion, that I think we can take that as fact.
We also have -- and I know this is opening a can of worms I don't particularly feel like addressing -- sufficient evidence to conclude the existence and non-triviality of anthropogenic warming, such that it's reasonable to infer that a causal link between human-created emissions and increased catastrophic behavior.
What isn't at all clear, and this is what your subsequent sentences correctly address, is how these effects lie within the broader scope of climatological evolution (no, not Darwinian, I have a limit as to how many buttons I plan to push in a single post), nor how policies impact this evolution. The very nature of catastrophic change is such that direct causation between a particular policy and a particular event is all-but-impossible, and correlation isn't much easier. That said, within that broader question, the necessity is clear: just because our policies might be subsumed within a broader sweep doesn't mean that we shouldn't change them to create less adverse effects (i.e. fewer emissions), any more than the prospect of winning the lottery should prevent us from saving some money for a rainy day. Or whatever appropriate metaphor you prefer that doesn't suck.
[And I should note I haven't seen any credible evidence for global dimming acting in the way you're describing here, although I've seen a few people pushing it as some kind "natural" counterbalancing to anthropogenic warming...]
That's completely correct and, for the purposes of my original point, utterly irrelevant. It is, however, vitally important to remember that when crafting policies that impact either the frequency or the severity of such phenomena in future.