In the process of development, the natural resource of developing countries are being depleted at an alarming rate. Human pressure on woods, pastures, streams, arable land, flora and fauna is leading to deforestation, soil erosion, lowering of the water table and loss of thousands of species.
Environmental problems created by economic development can damage human welfare either directly or indirectly. Direct damage includes damage to health (from lead poisoning, for example, or lung disease aggravated by air pollution), social disruption (i.e. displacement of people by mining operations or hydroelectric projects), and damage to the "quality of life" through congestion, noise, litter, etc. Indirect damage to human welfare occurs through interference with natural biological systems. For example, the filling of estuaries and the pollution of coastal waters diminishes ocean productivity; and logging or overgrazing can accelerate erosion. The long-term consequences for human beings of chronic exposure to low concentrations of environmental contaminants may be more serious that those of acute pollution. A deteriorating relationship between human populations and the natural systems that sustain them is a major contributor to deepening poverty in many regions. The most serious threats of all, however, may well prove to be indirect and generated by human disruption of the functioning of the natural environment.