ABSTRACT
The world population has never been as large as it is today and it is likely to increase to almost ten billion in 2050. Over the past century, a decline in mortality rates has caused an acceleration of the growth of the world population. However, in many countries fertility is decreasing, and that decrease is slowing global population growth. In this chapter, we illustrate how, over the course of several decades, changes in fertility and mortality can give rise to a different population structure. We explain how socio-economic changes cause demographic changes, and how demographic changes in turn can have major societal consequences. In doing so, we take micro-level cost-benefit analyses as our starting-point, and examine how these ultimately translate into population-level outcomes. We proceed to discuss an important dichotomy, namely that in most countries in Asia, Africa, and Latin America, fertility has started to decline only in the last few decades, whereas in Northern America, Europe, Japan, South Korea, and Russia, fertility has been below the replacement level for some time. In the former cases, population growth puts considerable pressure on available resources. In the latter, population ageing has started to strain the institutions of the welfare state.
