Diverse studies have shown that despite various efforts the state of our natural resources as well as the development of biodiversity and climate change are still a cause for concern. This is the case at the global level as well as at the level of individual countries and regions. In the industrialized countries in particular, they have been trying to solve environmental problems by regulatory means for many decades. And still the problems are increasing. It is not surprising, therefore, that different and complementary means of exerting influence have repeatedly been sought. Against this background, the attention given to economic instruments to resolve environmental problems has increased worldwide in recent years. In the wake of large international studies such as the "Millennium Ecosystem Assessment" of the UN and the international as well as national TEEB studies on the economic value of ecosystem services and biodiversity, there is growing interest in particular in Payments for Ecosystem Services, PES for short. How can this interest be explained, and what is the distinguishing feature of PES? The increased attention given to PES is closely related to the establishment of the ecosystem services approach, whereby a social and economic value is attached to nature. This is the basis of PES reasoning: When such a value is ascribed to an ecosystem service, then this value can be realized specifically at the moment when that service is scarce. Someone should be ready to pay money for a scarce ecosystem service. Hence the users of ecosystem services are the starting point of the discourse: Who uses clean drinking water? Who enjoys a scenice landscape? Who benefits when our rivers and lakes are less nutrient-rich? If we carry this further we can conclude that when the benefits decline ("we have an environmental problem!") those users would in their own self-interest pay to have the benefits restored or continued.