Human Population

The number of human beings on Earth has increased enormously during the past several millennia, but especially during the last two centuries: from 1850 to 1950 the human population doubled, from 1.265 billion to 2.516 billion, and has more than doubled from 1950 to the present. Moreover, it is likely that the human population—presently at over 6.215 billion—will continue to increase.

The recent growth of the human population has resulted in intense damage to the biosphere, representing a global environmental crisis. The degradation has occurred on a scale and intensity that is comparable to the enormous effects of such geological processes as glaciation. The impact of the human population on any one region, as on the biosphere as a whole, is a function of two interacting factors: (1) the actual number of people and (2) their per-capita environmental impact, which largely depends on the degree of industrialization of the society and on the lifestyles of individuals. In general, more damage is done to the earth to support a person living a highly industrialized lifestyle than to support one living a pretechnical-agricultural or hunter-gatherer lifestyle. However, a direct correlation between industrialized comfort and birthrate is often observed: the more well-to-do a population is (e.g., that of Europe or the United States), the lower its birth rate tends to be.