ABSTRACT
There are descriptive and there are prescriptive views on time discounting. A "descriptive" benchmark is provided by market rates of discount. "Prescriptive" views are closely related to the ideas of equity and fairness. Equity and efficiency may be separated when greenhouse policies are to be implemented within a decentralized market framework, and no major changes are proposed in the ownership of labor, capital, and other conventional resources. A commonsense way to describe equity-efficiency separability conditions is that global climate change will be limited sufficiently so that most prices and discount rates will not change much.
