到2050年，我们居住的城市将更加拥挤（在线收听）

By 2050, We will Live in a More Populous, Urban World

到2050年，我们居住的城市将更加拥挤

Demographers say India, China, Pakistan, Nigeria, Indonesia and Bangladesh will account for close to a half of the people born in the next 45 years.

Joseph Chamie: By far India is the leader, which gives about a fifth of all the world’s growth today.

Joseph Chamie, Director of Research at the Center for Migration Studies in New York, who served as Director of the United Nations Population Division for 25 years.

Joseph Chamie: The world is growing at 76 million people every year now and India contributes about a fifth of that. That’s followed by China, which is about ten percent and Pakistan at four percent; Nigeria, Indonesia and Bangladesh, each at around four percent.

By contrast, some 50 countries will see a decline in population, says Mr. Chamie. The Russian Federation is expected to lose the most in absolute numbers: about 31 million people, followed by Ukraine, which could lose 20 million, and Japan 16 million. Ukraine’s decline is especially noteworthy because it translates into a loss of 43 percent of its population, compared to 22 percent for the Russian Federation.

Overall, the world’s population is still growing. But demographers say the growth rate is slowing. William Butz, President of the Population Reference Bureau here in Washington, says that since then [the 1970s], people in almost every corner of the world have had fewer children. He says that 65 countries, which account for 43 percent of the world’s population, now have fertility rates at the replacement level, which is two children per couple on average.

William Butz: Principally it is because their desired fertility has gone down and they have the means to control their fertility. On the point of desired fertility, it’s because of education of women. It’s because of higher incomes, because of cultural norms shifting to smaller families. And on the side of the ability to control fertility, it’s the increasing accessibility and availability of modern family planning methods.

But some analysts note that in these methods are often unavailable to the poor. Jay Keller, National Field Director of the private non-profit group Population Connection also in Washington, says unlimited population growth puts a strain on the already scarce resources in many developing countries.

Jay Keller: What worries us the most is that rapid population growth is occurring in countries that are least able to absorb it and to deal with it: countries that don’t have a very good health care system right now, countries that don’t have very good retirement system right now. So that’s a huge challenge if you have a developing country that’s trying to just basically figure out how to feed people and how to provide education for children. And suddenly you have a birth rate that is in some cases going to double the population of that country in maybe 25-35 years.

Mr. Keller notes that people are moving to urban areas, creating “megacities,” such as Tokyo, Shanghai, Mexico City and Sao Paulo, often threaten the environment and strain resources.

But many analysts are optimistic, noting some significant improvements in the world’s living conditions in recent decades. Overall, mortality rates have declined and people live longer. Demographer Joseph Chamie says this means that the quality of life has improved for most of the world.

Joseph Chamie: I mean can you remember in many countries, the child can not remember their grandfathers because they died early. Now you have a chance not only to see your grandfather, but your great-grandfather and your great-grandmother. So you have many generations.

Demographers expect that by 2050, the global life expectancy at birth will have increased by at least ten years. But as William Butz of the Population Reference Bureau notes, this also means that the world population is slowly aging.

William Butz: Partly this is due to China, which after all, has about one fifth of the world’s population. And the Chinese population is definitely aging because their numbers of birth have been relatively slow now for decades. But it isn’t just China. The U-S, all of Western Europe, other countries with relatively low fertility rates, Thailand, you could also include South Korea and certainly Japan, are aging. In many parts of Africa, life expectancy is also going up. However, in Africa there are two things going on that countervail this. One is the relatively high fertility rates in many countries, almost all of the countries of sub-Saharan Africa, which keeps the number of young people high and keeps the population overall from aging. And the second is H-I-V /AIDS, which in many of these countries is devastating parts of the population.

By the middle of this century, the proportion of people in the world who are 65 years of age or older is expected to more than double, from seven to 15 %. Analysts say this will force countries with substantial aging populations to make long term plans for their continued employment, health care and retirement, something the United States is already doing. Some countries may also have to find a way to attract a younger immigrant labor force who, by paying taxes, will help finance government retirement funds and health care for the elderly.

Analysts predict that there will be demographic challenges ahead for the world. But, they say, history shows that problems can be overcome through informed policy making and careful planning for the future.

For focus, I’m Zlatica Hoke.

注释：

demographer [di:5mC^rEfE(r)] n. 人口统计学家

Bangladesh [7bB:N^lE5deF] n. 孟加拉国（亚洲）

noteworthy [5nEutwE:Ti] adj. 值得注意的，显著的

fertility rate 人口出生率，生育率

norm [nC:m] n. 准则，行为标准

megacity [5me^E7siti] n.（人口超过100万的）大城市

Sao Paulo 圣保罗

optimistic [7Cpti5mistik] adj. 乐观的

life expectancy 平均寿命

countervail [5kauntEveil] vt. 补偿，抵销