The gains in longevity registered worldwide over the last century are cause for celebration. Human populations have been able to sustain and extend the lives of most of their members to levels that would have been considered unattainable just a few decades ago. In turn, this unprecedented success in increasing survival has profoundly transformed the societies in which it has occurred, forcing us to address a number of unprecedented challenges. Firstly, population age structures have changed dramatically, with a considerable increase in the population above retirement age. This phenomenon is known as ageing and has major implications for the sustainability of the pension system and, more generally, the welfare state. Secondly, it is not entirely clear whether the increase in life expectancy has been accompanied by a delay in the age at which people\u2019s health begins to decline (i.e. the age of onset of morbidity). The relationship between mortality and morbidity can have enormous consequences for care and health systems, which need to ensure citizens\u2019 well-being. Finally, gains in health and longevity have not been shared equally across all sectors of societies, as they disproportionately benefit certain socioeconomic groups over others. In this article we will take a brief look at global trends in ageing levels over the past decades and present some of the main characteristics of a phenomenon that, while posing enormous challenges, also offers new opportunities for societies around the world.<\/p>\n\n\n\n
What is population ageing? We often feel that this is one of the biggest problems facing contemporary societies around the world, but its extent, determinants and main characteristics are often unknown. Far from being treated as a problem, ageing should be seen as one of the greatest collective achievements of the human species \u2013 yet it is one that brings with it a number of challenges.<\/p>\n\n\n\n
Population pyramids are perhaps one of the most characteristic and well-known graphs used by demographers around the world. They show the number of people in a given population, separated by age and sex. Figure 1 shows the population pyramids for three very different countries (Spain, India and Mali) for the years 1970, 2020 and 2070 (the latter pyramid is a projection made by the United Nations Population Division). As can be seen, the graphs are very different, both between countries and over time.<\/p>\n\n\n\n
In the case of Spain, we can see how the characteristic pyramid shape of 1970, with population numbers falling as age increases, had changed radically by 2020, and the pyramid of 2070 is also projected to be quite different from the previous two. The 2020 pyramid, and more so the 2070 pyramid, is characterised by a relatively thin base and a population size that varies greatly by age. The proportion of individuals over 65 years of age increases rapidly over time. The case of India shows a relatively similar pattern: it starts with the classic pyramid with a very wide base and ends with a relatively thinner base and a much higher proportion of people aged over 65. In the case of Mali, a country with limited economic resources, the age structure remains relatively stable over time and follows a pattern also observed in many African countries.<\/p>\n\n\n\n