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Saturday, 9 July 2011

The Growth of World Population Analysis of the Problems and Recommendations for Research and Training

The Growth of World Population Analysis of the Problems and Recommendations for Research and Training

World Population Problems


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 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.


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.

Front Matter (R1-R10)
Contents (R11-R12)
Introduction (1-2)
Conlusions (3-7)
World Population Problems (8-19)
Social Factors (20-27)
Bio-Medical Factors (28-36)
Summary Statement (37-38)

World population projections

Growing pains

Africa's populations look set to soar by 2100

ON MAY 3rd, the United Nations produced its two-yearly update of the world’s population, which includes projections. The numbers show small tweaks since 2008. The global population is likely to reach 7 billion in October 2011, not spring 2012. And it may still be rising in 2100 past 10 billion, rather than being flat by then. But the most dramatic changes are national, not global. America's population, now 310m, is likely to rise to 400m in 2050 and 478m in 2100. China's is forecast to fall by 400m between now and 2100. Russia’s population is now 142m; Afghanistan’s slightly more than a fifth of that; Niger’s barely a tenth. But by 2100, Afghanistan is forecast to have the same population as Russia (111m) and Niger will be larger. Such forecasts need to be taken with a bucketload of salt: tiny shifts in today’s birth rate extrapolated over 90 years produce huge changes. But the general picture is probably right. Sub-Saharan Africa’s current population, at 856m, is little more than Europe’s and a fifth of Asia’s. By 2050 it could be almost three times Europe’s and by 2100 might even be three-quarters of the size of Asia. By any measure, Africa is by far the fastest-growing continent.

The Growth of World Population Analysis of the Problems and Recommendations for Research and Training (1963)
National Research Council (NRC)

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