Jonah,
A few quick thoughts vis-à-vis your thread on global warming.
1. CO2 absorbs and redirects LW radiation. If you put more of it in the atmosphere, then, under any but pathological conditions, temperatures will rise over time. Being able to predict reliably how much warmer is another matter altogether.
2. You are right to be skeptical about the cost-benefit analyses, since it is hard to know what the economies of, say, the United States, China, and Germany will look like in the year 2100. That said, these cost-benefit analyses, unless you make indefensible discounting assumptions, generally support the basic “keep your options open in the face of uncertainty” approach that you are advocating.
3. In my opinion, the recent Scientific American article on discounting in global warming analyses is a terrible piece of work, and is symptomatic of the decline of a once-great magazine. Much more this later.