Tyler Cowen blogs about global warming:

Policy recommendations are extremely sensitive to the choice of discount rate, and economists do not agree on this issue. Furthermore most economists do not even know enough moral philosophy to understand the issues involved (and the philosophers don't understand enough economics), so there is no coherent consensus one way or the other.

I think this is key. Actually, I think there are four groups who need to be involved:

  1. Climatologists and associated scientists, to tell us what is likely to happen.
  2. Engineers, to tell us how me might abate what is likely to happen.

  3. Philosophers, to tell us how to handle issues of intergenerational equity. (Although to be sure, when I talk to my friends who are relatively expert in the philosophy of intergenerational equity, I don't emerge with any very clear answers on the topic.)
  4. Economists, to tell us what the likely effects of various actions will be on the lives of people in various generations.

To which we might add, "Political scientists, to tell us how to get everyone to agree to any solution the others work out."

No one understands very well the work of the others, which means everyone tends to overweight the urgency of their particular problem: the philosophers focus on justice, the engineers on feasibility, the climatologists and biologists on the various physical and biological changes, and the economists on the growth reduction; there's no very good system for weighting all of these considerations, except the political one, which everyone, including the politicians, seems to agree is doing a terrible job.

If we can solve the problem of letting China and India get rich without making the planet unbearably warm, or the industrialized countries unbearably poor, we will have this fundamental problem resolved. But the best the experts seem to have on that one is a sick look and a wan, "Well, we'd better find a way, hadn't we?"