Abstract

Nature can be valued in its own right or as an instrument for the benefit of humankind. The second valuation, although less fundamental from a philosophical point of view, is sufficient to substantiate conservation as a moral duty. The harm done to future human beings in burdening them with the prospect of life in an ecologically impoverished world cannot be justified by moral standards of a civilized society when we consider the fact that conservation costs are not excessive. Species and ecosystems can be thought of as economic resources possessing special properties: they can be irreversibly destroyed, their future usefulness is a matter of uncertainty, their services are difficult to replace and they exhibit properties of public goods. All aspects combined, prudence suggests that we must as far as possible prevent extinctions. Even from a purely anthropocentric point of view it is logically impossible to assess the full monetary value of an irreversibly destructible ecological asset because for this purpose we would need to know the valuations of all future human beings. It is meaningless, therefore, to ask how much money a species is ‘worth’. However, monetarization is possible within a limited scope. Many benefits obtained from species are amenable to evaluation in monetary terms. Independently, willingness-to-pay studies disclose the subjective value people place on species and biotopes. Despite numerous methodological problems, the costs of conservation can in most cases be assessed at least approximately. In principle, they amount to the maximum monetary benefit foregone if profitable but nature-adverse activities are displaced by conservation. Many empirical studies reveal low conservation costs by macroeconomic standards. In Germany, many conservation objectives in forests could be achieved virtually without any cost at all. A rather ambitious hypothetical conservation programme mainly for the agrarian countryside would bring about social costs of one thousand million DM per year. According to a first estimate, willingness-to-pay amounts to at least three thousand million DM per year.