Introduction: international migration and political polarisation

With the economic globalisation that coincided with the new millennium, migration flows accelerated, rose in volume and diversified. In Catalonia, as in the rest of Spain, this growth represented the first boom in international migration, from 2000 to 2007. Labour market demand during economic expansion, combined with the demand produced by outsourcing part of reproductive labour (domestic work and care of children and the elderly), largely explains this extraordinary increase in volume and acceleration.

The explosive rise in demand was driven both by a production model based on low value-added, employment-intensive economic sectors (from those related to tourism, particularly the hotel and catering industry, to agriculture and construction) and by demographic changes, notably greater life expectancy, education of younger generations, especially women, and the large-scale incorporation of women into the labour market. However, it was also motivated by political reasons: a weak welfare state challenged by neo-liberal doctrine. In terms of diversity, there are other types of migration besides purely economic: refugees; students and immigrants attracted by the property market; the consumption of the landscape and quality of life by such groups as retirees from richer countries and speculative investors; multinational workers; and digital nomads.

The novelty and magnitude of these flows contributed to the transformation of the labour market, mainly through its dualisation and deregulation, but they also put already deficient public services to the test, starting with schools, and health and social services in general. They led to the questioning of integration models, in response to which several narratives arose in relation to their consequences: the balance between cost and benefit, ethno-cultural diversity, its management, the impact on social cohesion and national identity.

With the second migratory boom, from 2014 to the present, after the experience of the Great Recession of 2008-2013 and the crisis caused by the COVID-19, Catalonia completed the leap from 6 million inhabitants, at which it had stagnated in the last quarter of the 20th century, to 8 million in 2023, a substantial part of which was due to migration – just over 3 million new residents registered in 23 years – which, after return and onward emigration movements, resulted in 1.9 million foreign-born residents in 2024. This figure brought the country’s international immigrant population to 23.8% of the total, comparable to Canada or New Zealand, among countries in the Organisation for Economic Co-operation and Development (OECD). Without the contribution of net migration (immigration minus emigration), the population would have dripped after 2016 due to natural decrease (the difference between births and deaths). This dizzying change, the experience of the recession and growing precarity and inequality, all of which has provoked acute social unrest, explain why migration narratives have become polarised in Catalonia and around the world, and are one of the central causes of political conflict. Political polarisation challenges the hegemonic discourse of interculturality. What can demography contribute to the debate?

Migrations and demographic reproduction

Unlike in Spain as a whole, immigration was nothing new for Catalonia. During the 20th century, it experienced two waves of migration from the rest of Spain: the first, from 1910 to the Great Crash of 1929, followed by the collapse aggravated by the Spanish Civil War (1936-1939); and the second, from the 1950s to 1976, brought to an end by the oil crisis, coinciding with the baby boom (1956-1976). Both waves shaped the demographic, economic and social history of the country. Let us now look only at the demographics (Figure 1).

Catalonia, like France as a whole and a few other European regions, was an exception in the demographic transition, which involved a switch from an old demographic model, based on high fertility and mortality, with little or no population growth, to a post-transitional one, with low mortality and fertility. This exceptionality was not so much in the chronology, which in Catalonia we can date to between the end of the 19th century and the 1930s, but in the fact that fertility began to fall early in relation to mortality. The latter remained relatively high at the beginning of the process, unlike most European countries and regions, where there was an initial fall in mortality followed later by a fall in fertility, leading to strong population growth. The reasons for this exception are still a matter for debate. Whatever the case, it meant that natural increase remained weak and that, with industrialisation, the pull factor of migration, due to the relative scarcity of young people entering the labour market, was at least as important or more so than the push factor of expulsion from immigrants’ regions of origin. This internal driving force has led some authors to speak of migration as an endogenous feature in Catalonia’s demographic system. [1]1 — Arango, J. (2007). “Les primeres migracions del segle XX a Catalunya”. In: Immigració. Les onades immigratòries en la Catalunya contemporània. Barcelona: Lluís Carulla Foundation, pp. 19-33 (Nadala; 41). Thus, the 20th century anticipated what has occurred to a greater or lesser extent in all developed countries during the 21st century: the migration balance becoming the essential component of population growth, overtaking natural increase. To put it in technical terms: Catalonia has become a complex system of demographic reproduction. [2]2 — Cabré, A. (1999). El sistema català de reproducció. Barcelona: Proa.

The two 20th-century waves of migration brought 455,000 and 1.3 million people to the country, contributing 76% and 55%, respectively, to total population growth in these periods. For its part, the overall, mainly international, migration of the 21st century, in a context of very low fertility and rapidly increasing life expectancy, has contributed 1.9 million people, compared with just over 200,000 people from natural increase, which, as mentioned above, has even been become negative in recent years.

Replacement migrations or population metabolism?

Migration that makes up for the relative shortage of young people in the labour market resulting from the decline in fertility, and thus in the number of births in previous decades, has been called replacement migration. The term became popular in the 21st century due to the publication of a report by the United Nations Population Division titled Replacement Migration: Is It a Solution to Declining and Ageing Populations? [3]3 — United Nations Population Division (2000). Replacement Migration: Is It a Solution to Declining and Ageing Populations?. New York: Population Division, Department of Economic and Social Affairs, United Nations. in the year 2000. This report sought to draw the attention of politicians and the general population to the benefits of migratory flows, which were rising alongside a strikingly ageing demographic. It also underlined the insufficiency of migration for reversing this ageing process and the resulting burden on public pension systems, and proposed a set of complementary measures. To illustrate this, population projections up to 2050 for various countries and regions of the world were provided, based on 1995 data and various assumptions: maintaining the total population, maintaining the working age population, maintaining the dependency ratio and maintaining the outcome in the absence of migration.

Both ambiguity in media coverage and self-interested reading had an adverse effect on the reception of this report. Pro-migration or pro-immigrant rights groups stressed the need for immigration to cover the demand for labour that local populations were failing to meet and to ensure the sustainability of the pension system, even though the report stated this was insufficient and that the estimated number of people needed to maintain the dependency ratio was unaffordable. By contrast, opponents of immigration and those in favour of curbing it took the hypothetical exercise as if it were a prophecy to be fulfilled at all costs, linking it to old conspiracy theories about a plot to replace the native population with immigrants, conveniently renamed as the Great Replacement.

Rather than so-called replacement migration, the concept that better helps us understand the impact of migration combined with trends in the birth rate is the term demographic metabolism. This refers to the succession of generations as a factor driving social change, in particular, the overlap of immigrants with smaller or larger generations, based on the size of their birth cohorts, their contribution to diversity of origin, of and between generations, their spatial distribution and the consequences this distribution has for the future. In the case of recent international migration, taking Catalonia as an example [4]4 — Osama, D.; Domingo, A.; Bayona, J. (2024). “Marcadores sociodemográficos y nuevas tecnologías en las generaciones catalanas 1926-2006”. Revista Internacional de Sociología, vol. 82 (1). DOI. (Figure 2), it is worth highlighting how, among the “empty generation” born between 1986 and 1995 (the so-called millennials) the percentage of population born abroad in the 2021 census, when they were between 25 and 34 years old, was as high as 39.9%, much higher than the 22.4% for the total population at that time. This figures rises to 44.6% when including those born in the rest of Spain.

However, if we look at migration movements in the 20th century, the percentage population of the millennial generation born outside Catalonia in 2021 is lower than that of the empty generation born between 1936 and 1945: for the same age group (25 to 34 year-olds), the percentage was 54.8% in the 1971 census (most of them born in the rest of Spain; only 1.2% were born abroad).

These proportions are higher for smaller territorial scales, if we take into account unequal territorial distribution due to the concentration and segregation of the immigrant population. By way of example, millennials born outside Catalonia in 2021 rose to 62.6% in the municipality of Salt, and 82% in the Ciutat Vella district of Barcelona. When considering ancestry, it should be noted that in the 2006-2015 generation, foreign-born inhabitants were still relatively few in the 2021 census, at 12.4% of the total, while foreign descendants born were double, at 28.5%. These proportions should prompt a rethink of the discourse of multiculturalism as a feature of the future (Figure 3).

Neither the decline in fertility nor the numbers of the resulting generations are in themselves the cause of migration: when it comes to workers, migration follows fluctuations in the economic cycle; they are not determined by the age structure of the population. Catalonia, despite the initial drop in fertility having influenced the incentive to migrate, is once again a good example: the arrival of international flows in the first boom was led by people born between 1956 and 1975 in the baby-boom generation, which occurred later than in northern European countries. However, with the Great Recession between 2008 and 2013, coinciding with young people from the 1980s empty generations entering labour market, some of these indigenous young people were forced to emigrate.

The belief in demographic determinism is part of what we might term demographic “common sense”. It is anchored in outdated paradigms of Malthusian demography based on the notion of equilibrium, whereby migrations are seen as an equalising factor in the structural differences between “young” and “old” countries or regions, between those with high and low fertility, as if it were the theory of communicating vessels, a kind of hydraulic mechanics of population. These narratives that shape demographic “common sense” found a new ally in those eager to shift structural economic causes to “demographic” ones, and from these to individual values and decisions. [5]5 — Domingo, A. (ed.) (2023). La coartada demográfica y el discurso de la involución en España. Barcelona: Icaria.

Migrations, demographic reproduction and social reproduction

We now turn to the on-going effect of the progressively central role of migration and the transition towards a complex system of demographic reproduction on Catalan society, especially on social reproduction. One of the reasons for the early drop in fertility in Catalonia among the working classes was the desire of families to invest in their children’s education to facilitate their upward social mobility. If the desire for social prosperity was a driving force in demographic change among the Catalan population, it is still a fundamental element in social reproduction strategies, also with respect to the immigrant population. The reason for economic migration, from the immigrant’s perspective, has historically been the desire to improve their own and their family’s living conditions, and this was no different in the case of Catalonia. If, from the outset, migration was part of the mechanism for reproducing the labour force – taking into account the low fertility rate – the aspiration to occupy upward social spaces, which is one way of defining what we call integration, became the beacon guiding immigrant workers in the 20th century. The Catalan language, which had become an anthropological marker of the country’s identity, would come to symbolise the integration process.

Sustained arrival of new waves of immigrants was essential for the reproduction of the capitalist system and, with it, social stratification. The first beneficiaries were therefore the wealthy classes who directly profited from the surplus value contributed by the workers. However, in general terms, these migrations also complemented the social promotion of, initially, indigenous workers, followed by earlier immigrants. In this way, the system set in motion a vacuum effect that fed on the progression of migratory flows. This strategy was only sustainable with a growing economy and a workers’ struggle that effectively won improvements in working and living conditions that would allow for upward social mobility. After being brought to a sudden halt by the Crash of 1929 and the Spanish Civil War, the trend returned in force in the 1960s with the rural exodus. Despite severe poverty and lack of freedom during the dictatorship, the end of economic autarky followed by the expansion of higher education to a three-tier system and universal access to studies, the second wave opened up opportunities for upward social mobility, which the grassroot political struggle against Franco consolidated. The family, together with the expansion of the civil service that occurred with the return of self-government, acted as a cushion from the economic crisis during the early years of democratic transition for many of those who had gone on to higher education – among both the native population and the children of immigrants. Flows in the rest of Spain stopped or went into reverse with return movements, while international flows were still low.

If we consider the effects of large-scale international migration in the 21st century on social reproduction, its major beneficiaries have undoubtedly been the private sector – as opposed to the public sector – and the middle classes and their offspring, threatened with social decline. It has been the cheapest way for young couples to reconcile work and family life in the absence of a strong welfare state. The first wave of the new millennium may even be considered to have contributed to the promotion of indigenous workers. However, in the aftermath of the Great Recession, it is worth asking whether we are not witnessing two unintended and interconnected effects. Firstly, we find segmented integration caused by structural racism, which is a source of prejudice and classifies migrants and their descendants into hierarchies based on their origin, phenotype and ethnocultural group, as has been described for other countries. [6]6 — Portes, A.; Zhou, M. (1993). “The New Second Generation: Segmented Assimilation and Its Variants”. Annals of the American Academy of Political and Social Science, no. 530, pp. 74-96. Such discrimination would result in ethnic stratification of the social pyramid, placing a new layer of the working class at the bottom, in which the African population would be the majority. Secondly and in parallel, a new underclass of the lumpenproletariat would have emerged, made up mainly of the poorly educated indigenous population, socially relegated by the process of economic globalisation.

A system in crisis?

When upward social mobility is threatened not only for immigrants, but also for the younger generation as a whole, this raises questions as to whether a system that leads to ever more intense waves is sustainable. To put it more bluntly: might we be on the verge of collapse? Migration is blamed for all manner of ills: from turning Catalan into a minority language to public insecurity. But what we really need to question, first of all, is the viability of a production model based on the large-scale contribution of workers and an economic order based on sustained population growth, all the while multiplying inequality and, with it, producing greater numbers of redundant population. Secondly, we must reflect on who controls the mechanisms of social reproduction in Catalonia, including control over the market, before laying the blame on demographic dynamics or structures, which, after all, have functioned as an adaptive system within the constraints of the economic order, as well as providing individuals with the best means to get ahead.

The inertia of ageing is unstoppable: according to our estimates, 14 million people would need to arrive in order to maintain the current dependency ratio of 25.4 per cent in 2050. [7]7 — Domingo, A.; Blanes, A. (2025). “Les migracions de reemplaçament a Catalunya: una mirada crítica”. Communication to the 4th Congress of Economy and Enterprise in Catalonia, organised by the Association of Economists of Catalonia. Barcelona. If we consider that in the 23 preceding years we have received 3 million people, this calculation seems totally unlikely. With the exception of the African continent, which will still grow substantially over the next quarter of a century, candidates for migration will become increasingly rare for demographic reasons, although crises in the global economic system will continue to drive people out of the Global South. Further movements can also be expected as a result of climate change.

• References

  1 —

  Arango, J. (2007). “Les primeres migracions del segle XX a Catalunya”. In: Immigració. Les onades immigratòries en la Catalunya contemporània. Barcelona: Lluís Carulla Foundation, pp. 19-33 (Nadala; 41).

  2 —

  Cabré, A. (1999). El sistema català de reproducció. Barcelona: Proa.

  3 —

  United Nations Population Division (2000). Replacement Migration: Is It a Solution to Declining and Ageing Populations?. New York: Population Division, Department of Economic and Social Affairs, United Nations.

  4 —

  Osama, D.; Domingo, A.; Bayona, J. (2024). “Marcadores sociodemográficos y nuevas tecnologías en las generaciones catalanas 1926-2006”. Revista Internacional de Sociología, vol. 82 (1). DOI.

  5 —

  Domingo, A. (ed.) (2023). La coartada demográfica y el discurso de la involución en España. Barcelona: Icaria.

  6 —

  Portes, A.; Zhou, M. (1993). “The New Second Generation: Segmented Assimilation and Its Variants”. Annals of the American Academy of Political and Social Science, no. 530, pp. 74-96.

  7 —

  Domingo, A.; Blanes, A. (2025). “Les migracions de reemplaçament a Catalunya: una mirada crítica”. Communication to the 4th Congress of Economy and Enterprise in Catalonia, organised by the Association of Economists of Catalonia. Barcelona.