The U. When immigration is also taken into account, the total population growth rate has been almost 1. Figure Overall, the world population is growing by about 80 million people annually. We saw evidence of this pattern when we looked at world population growth. When agricultural societies developed some 12, years ago, only about 8 million people occupied the planet. This number had reached about million about 2, years ago, and by the 15th century it was still only about million.
It finally reached 1 billion by about and by , only a century later, had doubled to 2 billion. Just 50 years later, it tripled to more than 6. Census Bureau, see Figure Source: Data from U. Census Bureau. Statistical abstract of the United States: Washington, DC: U. Government Printing Office. Eventually, however, population growth begins to level off after exploding, as explained by demographic transition theory , discussed later. We see this in the bottom half of Figure This rate has declined over the last few decades and is projected to further decline over the next four decades.
As Figure Still, even there the average number of children a woman has in her lifetime dropped from six a generation ago to about three today. Thomas Malthus, an English economist who lived about years ago, wrote that population increases geometrically while food production increases only arithmetically. These understandings led him to predict mass starvation. Wikimedia Commons — public domain.
Malthus identified these factors as war, famine, and disease Malthus Thinking practically, Malthus saw that people could produce only so much food in a given year, yet the population was increasing at an exponential rate.
Eventually, he thought people would run out of food and begin to starve. They would go to war over increasingly scarce resources and reduce the population to a manageable level, and then the cycle would begin anew.
Of course, this has not exactly happened. So what happened? There are three reasons sociologists believe we are continuing to expand the population of our planet. First, technological increases in food production have increased both the amount and quality of calories we can produce per person. Second, human ingenuity has developed new medicine to curtail death from disease.
Finally, the development and widespread use of contraception and other forms of family planning have decreased the speed at which our population increases. But what about the future? He advocated for a goal of zero population growth ZPG , in which the number of people entering a population through birth or immigration is equal to the number of people leaving it via death or emigration.
While support for this concept is mixed, it is still considered a possible solution to global overpopulation.
Fortunately, Malthus and ZPG advocates were wrong to some degree. Although population levels have certainly soared, the projections show that the rate of increase is slowing. Among other factors, the development of more effective contraception, especially the birth control pill, has limited population growth in the industrial world and, increasingly, in poorer nations. Food production has also increased by a much greater amount than Malthus and ZPG advocates predicted.
Widespread hunger in Africa and other regions does exist, with hundreds of millions of people suffering from hunger and malnutrition, but many experts attribute this problem not to overpopulation and lack of food but rather to problems in distributing the sufficient amount of food that exists.
Skip to content. Heard on:. Listen Now. Share Now on:. Embracing technology during the pandemic could help, says Chris Farrell. Sign up to watch, and learn, with us. Latest census data finds population growth in metro areas. Slow U.
Americans are having fewer babies, and it might have to do with the economy. Also Included in. Tags in this Story. Share this Story. The rights of children to be wanted, planned, and adequately cared for need to be supported. These aforementioned measures will help to reduce fertility, provide support for small families, and justify investment in social development. Population momentum will keep population growing for some time even with replacement level fertility.
Investment in adolescents through enhancement of self-esteem and promotion of later childbearing can lengthen the span between generations and slow population momentum. Population policies will be more effective when human rights are protected.
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