新闻是有分量的

时时彩天游平台'(2)

2019-05-01 10:34栏目:新闻

几乎所有的富裕国家生育率都低于更替生育率:经济合作与发展组织成员国的平均生育率为1.7。中等收入的国家的生育率为2.3,接近生育更替率。只有在贫穷国家,生育率仍然很高,促使人口迅速增长。撒哈拉以南非洲的生育率为4.8;重债穷国(世界银行如是称呼这些国家)的生育率为4.9。工业革命前的生育率只存在于最贫穷国度的最贫穷地区。

Notes

persist: v. Continue to exist; be prolonged.

eg: if the symptoms persist for more than a few days, then contact your doctor’

The decline in fertility in Africa was recently smaller than expected. If this is a long-term trend rather than a blip, then the world’s future population will be much larger than today’s. But Wolfgang Lutz, a demographer at the International Institute for Applied Systems Analysis in Austria, argues that it is indeed a blip. It happened because spending on education stalled during the 1990s. Many women born around 1980 received less education than the previous generation. The UN extrapolates from past trends, so the stalling in Africa makes its model predict higher fertility far into the future. However, the decline in education has reversed. The long-term trend is for ever more women to complete a basic education (see chart 1). After a lag (since schooling starts several years before puberty), this should allow fertility to resume its downward slide.

近来,非洲生育率比预计的降低得更少。如果这变成一个长期的趋势,而不是一个短期变化,那么未来世界人口要比当今世界人口大得多。但是就职于奥地利国际应用系统分析国际研究所的人口学家Wolfgang Lutz,认为这的确是由于20世纪90年代教育支出停滞所导致的一个短期变化。与前一代女性相比,许多出生在1980年左右的女性受到的教育更少。联合国从过去的发展趋势推测,非洲教育花费停滞使其模型推断出,在未来很长的时间里,更高生育率将会出现。但是教育花费的下降已经得到扭转。长期的趋势是越来越多的女性将会完成基本教育(见表一)。在一段延迟之后(因为学业是在青春期前好几年开始),生育率会继续呈现下降趋势。

Notes

Blip: n. An unexpected, minor, and typically temporary deviation from a general trend.

Extrapolate: v. Extend the application of (a method or conclusion) to an unknown situation by assuming that existing trends will continue or similar methods will be applicable.

eg: the results cannot be extrapolated to other patient groups.

Educated guesses

有依据的猜想

Models that take education into account produce wildly different projections. Mr Lutz and his team have produced a range. If progress in education and other social indicators stalls, the global population will be 12bn by 2100. If current progress continues, it will peak at 9.4bn in 2075 and then fall to 8.9bn by 2100. If progress is a bit brisker, the world’s population will peak at around 9bn and decline back to 7bn—today’s level—by 2100 (see chart 2). These estimates are based on three scenarios devised by climate-change wonks. Both the medium and optimistic ones are significantly lower than the UN’s 95% confidence range. To assess whether this is plausible, it is important to understand why some women have lots of children and others very few. A good way to start is to ask them.

将教育纳入考虑因素的模型作出的预测大相径庭。Lutz和他的团队算出了一个区域值。如果在教育和其他的社会指数所取得的进展停滞,到2100年全球人口总数将达到120亿。如果目前所取得的进展能继续,世界人口将在2075年达到峰值94亿,在2100年降低到89亿。进展如果更快一点,世界人口在90亿达到峰值,在2100年下降到今天的人口总数70亿(见图表2)。这些估算都基于由气候变化的专家所做出的三种设想。中庸和乐观的估算都要比联合国有95%信心的区间低得多。为了核实这是否可信,理解为什么一些女性生育很多孩子而一些女性只生育极少的孩子就显得十分重要。询问她们是一个好的开始。

Oumou Nyero lives in Torodi, a rustic district in Niger. She has had eight children, one of whom died. Though tragic, this is not unusual in rural Niger, where nearly one child in six dies before the age of five. Ms Nyero is 43 and assumes that her child-bearing days are over, unless God wills it. She is Muslim, conservative and veiled. Yet she is happy to discuss procreation, smiling and giggling as she does so. Giving birth eight times was not easy. Asked if any of her children were twins, Ms Nyero grins, raises her forefinger and says: “No. One. One. One. One.” At every “one” she waves her finger around and puffs out her face to emphasise how hard it was.