ABSTRACT
Current global demographic trends and the associated challenges are somewhat confusing to many observers. On the one hand, in many developing countries population growth rates are still very high due to birth rates well above replacement level (of two surviving children per woman) and a very young age structure. For this reason, in a number of countries the population is likely to double over the coming decades. On the global level, this leads us to expect that the world population will increase from its current 6.4 billion to somewhat below 9 billion by the middle of the century. On the other hand, there are an increasing number of countries in which the birth rates have fallen well below replacement level and the population is ageing rapidly. For these countries we expect a future of even more rapid population ageing and, in many cases, a shrinking of total population size. Because of these significantly different demographic trends, for some parts of the world there is still concern about the negative consequences of rapid population growth, while simultaneously in other parts there is concern about the negative implications of rapid population ageing.
