Today’s world is more demographically diverse than ever before. While the global population will continue to grow for decades to come, population growth is no longer the overriding reality for all countries. In Europe and East and Southeast Asia, for example, population decline is an increasingly common phenomenon, posing new challenges and opportunities to countries and entire continents. These shifts in population structure are characterised by a fall in fertility, rising life expectancy and population ageing, and the number of countries facing these changes is steadily increasing.