Explanation:
World Population Problems
THE GROWTH OF WORLD POPULATION
The population of the world, now somewhat in excess of three billion persons, is growing at about two per cent a year, or faster than at any other period in man’s history. While there has been a steady increase of population growth during the past two or three centuries, it has been especially rapid during the past 20 years. To appreciate the pace of population growth we should recall that world population doubled in about 1,700 years from the time of Christ until the middle of the 17th century; it doubled again in about 200 years, doubled again in less than 100, and, if the current rate of population increase were to remain constant, would double every 35 years. Moreover, this rate is still increasing.
To be sure, the rate of increase cannot continue to grow much further. Even if the death rate were to fall to zero, at the present level of human reproduction the growth rate would not be much in excess of three and one-half per cent per year, and the time required for world population to double would not fall much below 20 years.
Although the current two per cent a year does not sound like an extraordinary rate of increase, a few simple calculations demonstrate that such a rate of increase in human population could not possibly continue for more than a few hundred years. Had this rate existed from the time of Christ to now, the world population would have increased in this period by a factor of about 7×1016; in other words, there would be about 20 million individuals in place of each
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Suggested Citation:"World Population Problems." National Academy of Sciences. 1963. The Growth of World Population: Analysis of the Problems and Recommendations for Research and Training. Washington, DC: The National Academies Press. doi: 10.17226/9543.×
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person now alive, or 100 people to each square foot. If the present world population should continue to increase at its present rate of two per cent per year, then, within two centuries, there will be more than 150 billion people. Calculations of this sort demonstrate without question not only that the current continued increase in the rate of population growth must cease but also that this rate must decline again. There can be no doubt concerning this long-term prognosis: Either the birth rate of the world must come down or the death rate must go back up.
POPULATION GROWTH IN DIFFERENT PARTS OF THE WORLD
The rates of population growth are not the same, of course, in all parts of the world. Among the industrialized countries, Japan and most of the countries of Europe are now growing relatively slowly—doubling their populations in 50 to 100 years. Another group of industrialized countries—the United States, the Soviet Union, Australia, New Zealand, Canada, and Argentina—are doubling their populations in 30 to 40 years, approximately the world average. The pre-industrial, low-income, and less-developed areas of the world, with two thirds of the world’s population—including Asia (except Japan and the Asiatic part of the Soviet Union), the southwestern Pacific islands (principally the Philippines and Indonesia), Africa (with the exception of European minorities), the Caribbean Islands, and Latin America (with the exception of Argentina and Uruguay)—are growing at rates ranging from moderate to very fast. Annual growth rates in all these areas range from one and one-half to three and one-half per cent, doubling in 20 to 40 years.
The rates of population growth of the various countries of the world are, with few exceptions, simply the differences between their birth rates and death rates. International migration is a negligible factor in rates of growth today. Thus, one can understand the varying rates of population growth of different parts of the world by understanding what underlies their respective birth and death rates.
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Suggested Citation:"World Population Problems." National Academy of Sciences. 1963. The Growth of World Population: Analysis of the Problems and Recommendations for Research and Training. Washington, DC: The National Academies Press. doi: 10.17226/9543.×
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THE REDUCTION OF FERTILITY AND MORTALITY IN WESTERN EUROPE SINCE 1800
A brief, over-simplified history of the course of birth and death rates in western Europe since about 1800 not only provides a frame of reference for understanding the current birth and death rates in Europe, but also casts some light on the present situation and prospects in other parts of the world. A simplified picture of the population history of a typical western European country is shown in
Figure 1. Schematic presentation of birth and death rates in western Europe after 1800. (The time span varies roughly from 75 to 150 years.)
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