Demographics & Social Change

Season 2 · Introduction

What are demographics and social change?

Demographics is the study of populations. It is about how many people there are in the world, how old they live to be and how many children are born. Social change is what happens in society when those figures shift, for example how much goes to healthcare or how many people are of working age. The figures move slowly, year by year, but the difference becomes large if you compare a few decades back.

Take this figure as an example. In 1974, 5.5% of the world's population was 65 or older, about one person in eighteen. In 2024, fifty years later, the share was 10.3%, about one in ten. In other words, the share of older people has almost doubled in fifty years.

A large part of the explanation is how many children are born per woman, what is usually called fertility. In 1960 an average of 4.7 children were born per woman in the world. In 2023 the figure was 2.2 children per woman, close to what is called the replacement level, roughly the level at which one generation replaces the one before without growing larger. When fewer children are born compared with how many older people are already in the population, the share of older people rises by itself. It is a bit like a class photo where the older year groups stay in the picture while the younger rows behind them get smaller.

It may sound contradictory that the population is still growing. From 1960 to 2023 the world's population went from about 3 billion to just over 8.1 billion people. The explanation is that there are more women of childbearing age today than ever before, because earlier generations were larger. That means more children are born in absolute numbers, even when each woman has fewer on average. Still, fewer children per woman and longer lives pull in the same direction: an ever larger share of older people in the population, year after year.

So two curves meet in the middle of the population pyramid: fewer newborns at the base and more pensioners at the top, at the same time.

This shift is what lies behind the area of demographics and social change. When the share of older people grows and fewer young people are born at the same time, the pressure changes on healthcare, the labour market and research on the genome and ageing. The articles in this area go through each part in turn.

Education, not advice.