Food and Agriculture Organization of the United Nations- FAO
Payments for Environmental Services (PES) from Agricultural Landscapes
What are Ecosystem Services
Environmental Services
Provisioning services, such as food and timber, are generally produced intentionally for sale or direct consumption, but other ecosystem services are normally provided as unintended consequences of land management activities.
Provisioning services, such as food and timber, are generally produced intentionally for sale or direct consumption, and buyers and consumers can influence production through the market. However, other ecosystem services are provided only as "externalities" (6), in that they are unintended consequences of primary land management activities.
The term "ecosystem service" is sometimes used interchangeably with the term "environmental services". In this website, the term environmental services is used to refer to the subset of ecosystem services characterized as externalities.
Also, many services have the characteristic of "public goods" in that people usually cannot be excluded from benefiting from them, and the use of the service by one person does not diminish the availability of that service to other users (7). Nevertheless, people can degrade the capacity of ecosystems to supply these services, either through changing the composition and the structure of a system and how it works, or through extracting material from the ecosystem at a rate that is above the replenishment capacity of the ecosystem.
From an economic perspective, the most important cause of ecosystem degradation is the perception that many of nature's services are "free", in the sense that no one owns them and therefore no one has an incentive to preserve them. As a result, there are no direct market mechanisms to signal the scarcity or degradation of a service until it fails (at which point the non-market value of public goods becomes obvious because of the restoration or replacement costs).
This is partly why 70% of our planet's regulating services are in decline. In order to reverse this trend, the production of negative and positive externalities resulting from our current management of ecosystems must be made clear. For that, it is important to have a notion of how important these services are - see more in the next section of the value of ecosystem services .(6)An externality is a cost or benefit resulting from an economic transaction that is borne or received by parties not directly involved in the transaction. An externality occurs when the consumption or production of a good impacts on people other than the producers or consumers that are participating in the market for that good. Externalities can be either negative (e.g. water pollution caused by industrial production) or positive (e.g. the role of agriculture in maintaining the countryside and rural communities).
(7)Consumption of "Public Goods" is non-rival (consumption of the good by one does not reduce the amount left for others) and non-excludable (individuals cannot be excluded from consuming the good). Many ecosystem services, ranging from flood control to climate stability, provide non-rival and non-excludable benefits.
