The rapid growth in human numbers in the developing world imposes unsustainable burdens on the environmental-resource base that underpins much economic activity. While population growth is but one of many factors, it is an exceptionally significant factor. Indeed in many countries there is emerging a pronounced imbalance between the growth of population on the one hand and the natural-resource endowment on the other hand-albeit with much differentiated impact according to countries and development sectors. In a number of cases, we can soon expect to encounter a phenomenon of environmental discontinuities. That is to say, we shall find that environmental degradation and natural-resource depletion will suddenly and sharply worsen as a result of the demands of growing numbers of people, coupled with the cumulative burden of past over-exploitation. While much can be done to relieve the situation through amended policies in the economic and technological spheres, there is a premium on slowing population growth with all due despatch.