Carrying capacity: the tradition and policy implications of limits

Within just the last few centuries, science and technology have enlarged human capa- bilities and population size until humans now take, for their own use, nearly half of the Earth's net ter- restrial primary production. An ethical perspective suggests that potentials to alter, or further increase, humanity's use of global resources should be scrutinized through the lenses of self-inter- ested foresightedness and respect for non-human life. Without overtly invoking ethics, studies of the carrying capacity achieve just this objective. Carrying capacity is an ecological concept that expresses the relationship between a population and the natural environment on which it depends for ongoing sustenance. Carrying capacity assumes limits on the number of individuals that can be supported at a given level of consumption without degrading the environment and, therefore, reduc- ing future carrying capacity. That is, carrying capacity addresses long-term sustainability. World- views differ in the importance accorded to the carrying capacity concept. This paper addresses three world-views - ecological, romantic, and entrepreneurial - and explores the ethics and the policy implications of their contrasting perspectives.