Valuing and paying for ecosystem services: a pre-condition for sustainability

The paper addresses the socio-economic importance of ecosystems and the valuation of ecosystem services. Principles and examples of valuation and payments for ecosystem services (PES) are reviewed and compared. Special emphasis is given to waterrelated ecosystems. Markets for ecosystem services are discussed, and future developments are put into perspective. Conclusions for policies on PES, based on a number of recent conferences, are formulated.