The main conclusion of the Nordhaus analysis is that the ambitious proposals, "Stern" and "Gore," are disastrously expensive, the "low-cost backstop" is enormously advantageous if it can be achieved, and the other policies including business-as-usual and Kyoto are only moderately worse than the optimal policy. The practical consequence for global-warming policy is that we should pursue the following objectives in order of priority. (1) Avoid the ambitious proposals. (2) Develop the science and technology for a low-cost backstop. (3) Negotiate an international treaty coming as close as possible to the optimal policy, in case the low-cost backstop fails. (4) Avoid an international treaty making the Kyoto Protocol policy permanent. These objectives are valid for economic reasons, independent of the scientific details of global warming.
