The world’s population is likely to peak at 9.7 billion in 2064, and then decline to about 8.8 billion by the end of the century, as women get better access to education and contraception, a new study has found.

By 2100, 183 of 195 countries will not have fertility rates required to maintain the current population, with a projected 2.1 births per woman, researchers from the Institute for Health Metrics and Evaluation at the University of Washington’s School of Medicine said.

Some 23 countries — including Japan, Thailand, Italy, and Spain — will see populations shrink by more than 50 percent, researchers said.

The modeling study, published Tuesday in The Lancet, also forecasts dramatic declines in working-age populations in countries including India and China.

But as fertility declines, researchers note that immigration could offset population shrinkage, particularly in countries with low fertility, such as the U.S., Australia and Canada.

“The world, since the 1960s, has been really focused on the so-called population explosion,” said Christopher Murray, who led the research. “Suddenly, we’re now seeing this sort of turning point where it is very clear that we are rapidly transitioning from the issue of too many people to too few.”

Using data from Global Burden of Disease Study 2017, researchers predicted that the fastest-shrinking populations will be in Asia and eastern and central Europe.

The report authors project that the population of Japan will shrink from around 128 million people in 2017 to 60 million in 2100, Thailand will see a shrink from 71 to 35 million, Spain from 46 to 23 million, Italy from 61 to 31 million, Portugal from 11 to 5 million, and South Korea from 53 to 27 million.

Murray said that not only will the population shrink, but society will generally be older, which would have a substantial impact on economic growth.

“There’re more people needing to receive benefits from the government, whether that’s social security or health insurance, and there’re fewer people to pay taxes,” he explained.

Researchers project that the population of sub-Saharan Africa could triple over the course of the century, from an estimated 1.03 billion in 2017 to 3.07 billion in 2100.

North Africa and the Middle East are the only other regions predicted to have a larger population in 2100 than in 2017.

Words to Learn 相关词汇

【避孕】bìyùn contraception deliberate prevention of conception or impregnation

【抵消】dǐxiāo offset counterbalance, counteract, or compensate for

一项新研究发现，随着女性有更多机会接受教育和采取避孕措施，世界人口可能会在2064年达到97亿的峰值，然后会在本世纪末降到约88亿。

华盛顿大学医学院健康指标与评估研究所的研究人员称，到2100年，195个国家中有183个国家的生育率将不足以维持现有人口，预计平均每位女性生育2.1个孩子。

研究人员指出，包括日本、泰国、意大利和西班牙在内的23个国家的人口将缩水超50%。

这篇7月14日发表在《柳叶刀》上的模拟研究还预测，印度和中国等国的劳动年龄人口将剧减。

随着生育率的下降，研究人员指出，移民可以抵消人口缩水，尤其是在生育率低的美国、澳大利亚和加拿大等国家。

这项研究的领头人克里斯多夫▪穆雷说：“自从20世纪60年代以来，世界一直在关注所谓的人口大爆炸。突然间，我们发现了这一转折点，显然我们正在从人太多的问题迅速过渡到人太少的问题。”

运用2017年全球疾病负担研究的数据，研究人员预测人口减少最快的地方将是亚洲、东欧和中欧。

研究报告的作者们预计，日本人口将从2017年的约1.28亿减少到2100年的6000万，泰国将从7100万减少到3500万，西班牙将从4600万减少到2300万，意大利将从6100万减少到3100万，葡萄牙将从1100万减少到500万，韩国将从5300万减少到2700万。

穆雷称，不仅人口会缩水，社会年龄结构也会整体老化，这将对经济增长产生重大影响。

他解释道：“更多人需要从政府领取福利金，无论是社保金还是医保金，而纳税的人更少了。”

研究人员预计，撒哈拉以南非洲人口将在本世纪末增至原来的三倍，从2017年的10.3亿左右增加到2100年的30.7亿。

除了撒哈拉以南非洲，预计人口会增加的地区只有北非和中东。

(chinadaily.com.cn)