世界人口下降危机 世界人口将在2064年达到峯值后开始下降

世界人口将在2064年达到峯值后开始下降  

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%
researchers said.
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%。
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 US
Australia and Canada.
"The world
since the 1960s
has been really focused on the so-called population explosion
" Dr Christopher Murray
who led the research
told CNN. "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's more people needing to receive benefits from the government
whether that's social security or health insurance
and there's 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 is the only other region predicted to have a larger population in 2100 than in 2017
with a predicted 978 million pared to 600 million.
The study also predicts major changes in the global age structure as fertility falls and life expectancy increases
with an estimated 2.37 billion people over 65 years globally in 2100
pared with 1.7 billion under the age of 20.
The global number of people older than 80 could increase sixfold
from 141 million to 866 million. Meanwhile
the number of children under the age of five is forecast to decline by more than 40% -- from 681 million in 2017 to 401 million in 2100.