On the Welfare Significance of Green Accounting as Taught by Parable.

"Green NNP" is a national accounting concept that substracts off from GNP not just depreciation of capital, but also depletion of environmental assets evaluated at competitive of efficiency prices. Recent literature shows that, for a time-autonomous technology, Green NNP has regorous welfare interpretation as an exect measure of the economy's future power to consume. The present paper extends the basic framework to cover the case of labor-augmentating technological progress. For this special case of time dependence, a powerful conceptual of parable applies. It is 'as if 'the conclusion from a simple-minded welfare story told by the standard neoclassical one- secort growth model covers a far more general situation involving any number of different types of capital, any convex production prossibilities set, and fully optimazing behavior. Implications and applications are discussed.