A method for valuing global ecosystem services

The goal of this paper is to provide an investigation of several approaches to valuing ecosystem services and to contribute additional techniques which may be used in evaluating 'green' GDP accounts. Our estimates focus on the ecosystem as a productive economic input, not a stock which is depreciated or depleted over time; as such, it differs with other concepts more frequently employed in green GDP accounting. Most of our results are derived from the analytical fiction that a single owner of the biosphere establishes a market for all ecological resources. This monopolist then appropriates all rents from the human population. The maximum amount the monopolist charges is first assumed to be world gross product less the global human subsistence level. In addition, we examine the excess rents available in factor markets using the assumption of weak complementarity between factor inputs and ecosystem services. We also provide more conservative estimates of the value of ecosystem services by investigating the sustainable price the monopolist could charge the global population and by exploring the effects of compensating wage differentials and a non-monopolist owner of the ecosystem. (C) 1998 Elsevier Science B.V. All rights reserved.