Suppose there's a 10% chance that the Gulf Stream will turn off (an event which has previously occurred, and which was followed by extreme rapid cooling of northern Europe), given one set of policy choices, and a .1% percent chance, given another set. How much should we be willing to pay to implement the second set?

The thing that always gets me about this debate, and the energy debates in general, is that energy efficiency is still far and away the most productive energy investment around: what is needed is ways for individual consumers to make those investment easily.