Non market valuation and bio economic modelling are combined in a dynamic model of ecosystem services. A mathematical proof demonstrates that the imputed price of natural capital contains all non market values and that scarcity rent is the total value of ecosystem services. A dynamic demand system, including characteristics is derived. New methods are developed for dynamic welfare analysis and both revealed and stated preference methods are proposed for estimating the price of natural capital. Estimation is simple if we avoid surveying consumers who degrade the ecosystem and instead consult owners who accrue the scarcity rent and conserve for the future.