Ecosystem services in theory and practice

The ecosystems of the world generate processes that provide values to human well-being. Thus, these systems function as a kind of natural capital, in that they are a stock that yields a flow of services over time. These ecosystem services generate benefits to societies in the form of clean air, water, fiber, and food, among others. They provide a challenge to traditional economics in developing appropriate ways to assign value. The Millennium Ecosystem Assessment developed a categorization of these services into four broad themes: provisioning, regulating, cultural, and supporting. How we value these services is critical for developing models of sustainable use to guarantee that we do not exhaust this natural capital. This will require economic models that give consideration to economic, ecological, cultural, and social valuations in an integrated fashion.