2018-02-14
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The globalization of the world is bringing people together, making them increasingly interconnected and interdependent. Distance is diminishing in the crowded "global village." Population growth is altering how people interact and threatens to transform humanity's long-term prospects for survival. These changes raise new questions and create new issues. How many people can the earth support? The planet's carrying capacity –its ability to support human and other life forms – is not infinite. However, human ingenuity and rapidly advancing technology have continuously stretched the boundaries. As a result, the earth will doubtless accommodate the growth projected for today's 6 billion inhabitants into the next decades. But at what cost – to human freedom, human welfare, and the environment?
Global demographic patterns and trends
The dramatic growth in world population in the twentieth century was historically unprecedented. It took 2 million years before world population reached l billion in 1804; 2 billion was reached in 1927. Since then, additional billions have been added even more rapidly: 3 billion was reached by 1960, 4 billion in 1974, and 5 billion in 1987. The sixth billion was added on the eve of the twenty-first century. How is this possible? Because world population grows by nearly ten thousand each hour of every day and is increasing at a record pace, "we add a New York city every month, almost a Mexico every year, almost an India every decade" (McKibben). In fact, more people were added to the world's population in the last fifth of the twentieth century than at any other time in history. If present trends continue uninterrupted, world population will grow to 7.5 billion in 2015, stand at 9.8 billion in 2050, and reach 10 billion only a few years later – about the time most of today's college students in the Global North will be drawing on their retirement benefits. Indeed, most students reading this unit will have witnessed the largest population surge ever to have occurred in a single generation – theirs.
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As difficult as it may be to imagine a world with half again as many people as today, 10 billion is less than what was once projected for the middle of the twenty-first century. The latest projection – what the United Nations calls its "medium variant" – depends on the assumption that the world fertility rate will continue to decline, as it has for more than a decade, and will eventually settle at a point where couples only replace themselves. Without that, population growth could be much more rapid in the first half of the twenty-first century, reaching 11.9 billion in the year 2050, nearly five times the 1950 population. In either case, world population will continue to grow throughout the twenty-first century and into the twenty-second. On the other hand, should world fertility slow more rapidly, world population would also grow more slowly and eventually settle at a level much lower than now seems most likely.
The rapid growth of world population after reaching 2 billion in 1927 is described by a simple mathematical principle articulated in 1798 by the Reverend Thomas Malthus: Unchecked, population increases in a geometric or exponential ratio (e.g., l to 2, 2 to 4, 4 to 8, etc.), whereas subsistence increases in an arithmetic ratio (l to 2, 2 to 3, 3 to 4). When population increases at such an accelerating rate, the compound effect can be staggering. Consider, for example, how money deposited in a savings account grows as it earns interest not only on the original investment but also on the interest payments. If each of our ancestors had put a mere ten dollars in the bank for us two hundred years ago, and it accrued a steady 6 percent annual interest, today we would all be millionaires! Population grows in the same way: It is a function of increases in the original number of people plus those accruing from past population growth. Thus a population growing at a l percent rate will double in sixty-nine years, while a population growing at a 2 percent rate will double in only thirty-five years. (The impact of different growth rates on doubling times can be calculated by dividing sixty-nine by the percentage of growth.)
Worldwide, the rate of population growth peaked at just over 2 percent in the late 1960s and then declined to just under 1.6 percent by the mid-1990s. Hence the projection that world population in 2050 will be far less than once thought. Not all countries will share equally in the phenomenon, though. In fact, rapid population growth in the Global South is the most striking demographic development in the post-World War II era, and its consequences will continue to be felt well into the future.
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During the next fifty years the developed and the developing worlds alike will experience declining population growth rates, but the incremental contributions of the Global South to expanding world population will actually increase. "Whereas 79 percent of the annual increase in world population between 1950 and 1955 originated in the less developed regions, 95 percent of the increment between 1990 and 1995 originated in those regions. It is expected that by 2045-2050 all of the net population growth in the world will arise in the less developed regions, as the population of the more developed regions is expected to be declining in absolute numbers" (World Economic and Social Survey 1995). The world has become, and will remain, demographically divided. To better understand the inevitability of this prediction, and how demographic developments will affect world politics, we must go beyond the simple arithmetic of population growth to explore its dynamics.
Exercises:
1 Answer the following questions:
