Ageing and migration. Reflection on an emerging nexus and application to the Middle East and northern Africa

Abstract

How does ageing affect migration systems and migrants' lives? Addressing this question, one must make a distinction between individuals and populations. Ageing of individuals from birth to death is unavoidable, continuous and irreversible. Every day that passes, any individual gets older by 1 day and there is no way to change the fact.In contrast, ageing of populations refers to the elevation of age structure-related indicators such as the median age and the proportion of old persons. It is an avoidable, discontinuous and reversible process. Any population can get older or younger as a result of the complex interplay of entries by birth or immigration, and exits by death or emigration. Focusing on either individuals' life cycle or the whole population presents two perspectives on the relationship between ageing on one side and the economy, well-being, human progress and migration on the other.From a life cycle perspective, ageing could be good. An individual's economic contribution tends to increase with age, up to a certain limit. According to neuroscience, cognitive performance peaks early in an individual's life, at around 30 years. But according to economics, experience and accumulated knowledge make up for eroding cognition, and human capital benefits from an age dividend. Locating the high point in human capital accumulation is difficult, but looking at inventoried accomplishments offers a proxy: great achievements are produced at 40 years on average (Jones, 2010) and, while the quantity of inventions peaks at around 40 years, their quality remains stable at older ages (Frisch, 2009). Though losing physical strength with age, one gains intellectual skills. Since workers tend to adjust their activity to their capabilities, they make an increased use of intellectual skills while ageing (Bowlus et al., 2016). Moreover, there are differentials in age at retirement from the labour market. The less skilled and less specialised retire earlier so that the average level of skills in a given cohort of workers increases with age. It has been argued that tapping the potential of older people to participate productively in society should represent a longevity dividend (Rowe, 2015). i From a population perspective, however, ageing may harm. Around a hundred annual birth cohorts are stacked in one population, and successive cohorts differ in terms of the quantity and quality of knowledge and skills they have acquired. Formal education gained at school ends at ca. 25 years, after which age it remains unchanged except for what is acquired outside school. If knowledge measured by the level attained at school does not change over one generation's lifecycle, it does from one generation to the next. In a context of lengthening school education,