Population and the environment: The scientific evidence
Citation: Preston, Samuel H., Demeny, Paul, McNicoll, G. (editors) (1998) Population and the environment: The scientific evidence.
Population growth has contributed and is contributing to a variety of environmental changes. Some, but not all, of these changes would be classified as ailments or degradations. There is clearly an association over time between population growth and loss of forest. The most significant agent of forest destruction is the encroachment of slash-and-burn cultivators (Myers 1991). In tropical areas, the response to population growth more often takes the form of occupying new land rather than of intensifying production on old land (Grainger 1990). I=PAT: Environmental impact is expressed as a product of population size, production per capita, and impact per unit of production. This formula defines away the issue. Humans create institutions that can mitigate the environmental impact of population growth. The most important of these institutions are those that govern ownership and access to natural resources, especially land. Land tenure systems are very important. A second factor that affects the preservation of resources is the availability of credit. Unfortunately, ownership rights are typically most ambiguous, administrative structures weakest, and credit markets more inefficient in the frontier areas of developing countries where forests are being destroyed. Other important factors are biased agricultural prices and exchange rates, adverse tax policies, weak agricultural extension services, excessive government control, and civil wars.