2006年VOA标准英语-World Population Growth to be Concentrated（在线收听）

By Michael Bowman
Washington
07 March 2006 

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By 2050, world population is projected to reach nine billion people. That would constitute a 38 percent jump from today's population total of 6.5 billion, and more than five times the 1.6 billion people believed to have existed in 1900. Demographers foresee declining, more aged populations in many industrialized nations, and explosively-growing, ever-younger populations in much of the developing world. VOA's Michael Bowman reports from Washington, both trends are seen as problematic.

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If projections hold true, future global population growth will be heavily concentrated in Latin America, Africa and South Asia. Carl Haub is senior demographer at the Washington-based Population Reference Bureau. "All world population growth today is in the developing world. There is no natural population growth in Europe, and even the U.S. is very heavily dependent on immigration," he said.

By 2050, Africa's population, both northern and sub-Saharan, is expected to surge from 900 million to almost two billion, while South Asia's population is projected to swell from 1.6 billion to nearly 2.5 billion. At the same time, Europe's population is expected to shrink from 730 million to 660 million.

Haub has sobering words for African governments worried about resource management in the face of explosive population growth, or European governments concerned about providing for an increasingly aged population: in the short-term, little can be done. "Demographic momentum is such that you cannot change something overnight. We cannot go back and have the babies we should have had in 1985. Whatever goal you might set, you have to start doing something about it about a generation ahead of time," he said.

The bottom line is that fertility rates will likely remain low in regions where babies are most-wanted from a public policy standpoint, and highest in many regions where poverty and hunger are already prevalent. The United Nations Population Fund's Africa Director, Fama Hane Ba, says many developing nations are struggling to provide for their current populations, and could be overwhelmed by future demographic growth. "One of the consequences is the tremendous challenges to the countries, the governments and the populations to take care and to provide [for] social services, to these growing populations, and also employment opportunities," he said.

Experts also foresee increased urbanization in the developing world. Elizabeth Chacko, who teaches geography and South Asia studies at George Washington University, come from India, which is expected to account for one-fifth of world population growth over the next 50 years. "When you think about population growth at large, there is the density factor. People do not just spread evenly across the country. They are crowded in the cities, they are crowded in the coastal plains. And that makes for all kinds of problems. We know that with higher density there are often higher rates of crime, greater chance of the spread of epidemics," she said.

But Chacko notes that population growth can also generate a larger workforce and a bigger consumer base, both of which tend to propel economic growth.

At the Washington-based American Enterprise Institute, demography expert Nicholas Eberstadt warns that 50 year population projections can prove inaccurate, since they involve predicting the reproductive habits of a generation that has yet to be born. Nevertheless, to the extent that rapid population growth is anticipated in the developing world, he says it need not spell disaster for the poor. "In low-income areas there is continuing population growth. Does that mean unemployable people, or does that mean a vibrant workforce? It depends an awful lot on the sorts of policies and institutional settings in which one finds oneself. That seems to me to be a good argument for getting policies right and institutions good, rather than trying to fine-tune the birthrate," he said.

Eberstadt makes a similar argument for industrialized nations, noting that efforts by European governments to promote higher birthrates have met with little success. "Inducing women to become - let's call them 'baby ranchers' - is a very expensive proposition when women have alternative occupations in the paid labor force. Most Western European countries have tried to 'talk up' the birth rate, and not surprisingly that does not work too well," he said.

Chacko notes that many developing nations have programs to promote contraception. She says she sees a common thread in regions where those programs have proven most successful: the empowerment of women. "Kerala [state] in southern India has had one of the lowest fertility rates [in the country] and everything we know about Kerala suggests that the women in the state have a high status; they have been educated; they have been working for a long time. And research has shown that even a few years of education can have a great impact on fertility rates, because this is a woman who can read, who can understand the kind of birth control she might want to use - but also be empowered to use it," she said.

Among developed nations, the United States is an enigma. Unlike Europe, the U.S. population is expected to increase by one-third by 2050. Demographers note that the United States continues to receive large number of immigrants, predominantly from Latin America, and that immigrants tend to have higher birthrates than the domestic population as a whole. They also note that higher standards of living allow many American women to successfully rear children on their own, and that American men generally share child rearing duties to a larger extent than their counterparts in other nations.