One person suggested that I look to the IPCC report on global climate change. Now the IPCC 2001 report does have a a report on Impacts, Adaptation and Vulnerability but this report reaches no real conclusions, instead couching it’s conclusions in statements like the following.

Even though increased CO2 concentration can stimulate crop growth and yield, that benefit may not always overcome the adverse effects of excessive heat and drought.

This is exactly the way that the IPCC should report on the economic issue. Their credibility depends on only endorsing the strongest most clear cut scientific consensus and it is far more important for them to maintain this credibility than to give clear economic guidance. While the models they propose are useful they don’t truly provide much guidance for someone who is trying to quantify the costs to a future richer society of dealing with climate change at that time compared to the costs of various solutions implemented now.

Moreover, I’m not sure this is something that is best addressed by an organization like the IPCC since I suspect that actual policy choices may be primarily determined by the risk of low probability but extreme events like large scale wars breaking out or the extreme end of the climate predictions turning out to be accurate. Certainly what we need first is much more publicly visible work by economists to boil down the conclusions of various climate models to approximate costs and benefits using reasonable assumptions. At this point what is needed isn’t precise answers but merely order of magnitude calculations to get a sense of what magnitude response is required.