The UN projects a decline in population to around 630 million in 2050, from around 725 million people today. With few children and longer life expectancy, the median age of the population rises sharply in this forecast, from 39 years in 2005 to around 48 years in 2050.
而在欧洲，人口增长趋势正好相反。联合国预测欧洲的人口数量到2050年将由现在的7.25 亿下降至6.3亿。由于出生率低以及人的寿命长，欧洲人口的中位年龄到2050年将由2005年的39岁快速老化到大约48岁。