Demography makes no noise. It changes a society slowly, almost imperceptibly, until the consequences become visible everywhere at once. A child born today will vote in eighteen years. Someone who immigrates today will affect tomorrow’s labor market, housing demand, and schools. His or her children will later become part of the electorate. Population projections are therefore not dry statistics. They are political maps in slow motion.

The French article La Commission a un problème de bébés identifies a problem that European governments prefer to treat as a technical matter. Europe is having too few children. Its population is aging, while the group expected to sustain the welfare state is becoming smaller. Yet anyone who looks only at the total population misses the most consequential development. Europe will not merely shrink. It will acquire a different population, with different ages, different backgrounds, and ultimately different political preferences.

The figures reveal more than decline

According to the latest Eurostat projection, the European Union had approximately 452 million inhabitants in 2025. After a modest peak around 2029, that number is projected to fall to roughly 399 million by 2100 — a decline of almost twelve percent.

The real shock lies beneath that headline figure. The number of people aged twenty to 64 falls from about 263 million to 198 million. At the same time, the population aged 65 and over rises from 99 million to almost 134 million. Today, there are arithmetically 2.66 people aged twenty to 64 for every person over 65. By 2100, there will be only 1.48.

The official baseline projection already assumes substantial immigration. Between 2025 and 2100, Eurostat expects approximately 253 million births and 410 million deaths. Europe therefore loses almost 157 million inhabitants through natural population decline. A cumulative positive migration balance of about 104 million limits the final loss to 53 million. Without net migration, the European Union would have approximately 269 million inhabitants in 2100, rather than 399 million.

Immigration is not a footnote in this projection. It offsets about two thirds of the natural population loss. As a result, the share of residents with a recent migration background, or with parents and grandparents who immigrated, increases. Europe’s older, predominantly native-born generations are dying more quickly than births replace them. New immigrants and the children of earlier immigrants consequently account for a growing proportion of younger age groups.

This does not mean that Europe’s economy must automatically collapse. If productivity stopped growing, the smaller potential workforce would, in this simple calculation, push European GDP about 9.5 percent below its 2025 level by 2050 and almost 25 percent lower by 2100. With annual productivity growth of only 0.75 percent, however, total GDP would be roughly nine percent higher in 2050 and more than thirty percent higher in 2100. Aging is therefore not a death sentence, but it is an ultimatum: without higher productivity, automation, and labor-force participation, the bill becomes unaffordable.

Europe will become more Muslim

Religion is not recorded consistently in population statistics across Europe. There is therefore no precise EU-wide figure projecting religious composition to 2100. The direction is nevertheless clear: the Muslim share of Europe’s population is likely to grow.

On January 1, 2025, 10.4 percent of the EU population had been born outside the Union. In 2024, 24 percent of children born in the EU had a mother who had herself been born abroad. This is not a Muslim percentage — it includes, for example, a Polish mother in the Netherlands or a Ukrainian mother in Germany — but Eurostat’s data on origin and fertility demonstrate how rapidly the composition of younger age groups is changing.

The best-known religious scenarios come from Pew Research Center. For the then EU plus Norway and Switzerland, Pew began with a Muslim share of 4.9 percent in 2016. Even with no further migration, the younger age profile and higher fertility rate would raise that share to approximately 7.4 percent by 2050. Under continued regular migration, it reached 11.2 percent. Only if the exceptionally high refugee inflows of 2014–2016 continued indefinitely did the model reach fourteen percent.

Europe therefore becomes more Muslim in every scenario, but Muslims do not form a majority by 2050 in any of them. The eventual scale of the change depends on immigration, secularization, mixed relationships, and the degree to which fertility rates among different population groups converge.

A simple calculation shows how important that last assumption is. Suppose a hypothetical Muslim population represents five percent of the population in 2025 and has an average of 2.4 children per woman, while the rest remains at 1.34. If this difference persists unchanged for three generations and children consistently retain their parents’ group identity, the Muslim share rises to approximately 23 percent by 2100. If its fertility rate falls over those generations from 2.4 to 1.8 and then to 1.5, the same model ends at around eleven percent.

The future will probably lie somewhere between such extremes. National averages also conceal local concentrations. A group representing ten percent nationally may form a much larger share in particular cities, neighborhoods, schools, and younger age categories. Mosques, Islamic schools and associations, religious practices, and political organizations built around Muslim communities will therefore become more visible and influential. There will be no sudden Muslim majority, but there will be a gradual shift whose local effects may be much stronger than national figures suggest.

The ballot box changes as well

People are not voting machines, and background does not determine someone’s party preference for life. Nevertheless, a different population composition inevitably changes the political landscape. Age, income, home ownership, religion, employment and reliance on public services all influence political interests.

A study in the Journal of Urban Economics, based on voting behavior in 22 European countries, finds that second-generation immigrants vote further to the left on average than comparable residents without a migration background. They are more likely to support government intervention to reduce income inequality, internationalism, and multiculturalism. A father’s difficulty integrating into the labor market is a particularly strong predictor of this more left-wing preference.

A growing second generation therefore creates more electoral space for parties promising redistribution, social housing and expanded public services. The effect is not yet large enough to determine national elections on its own in most countries. Its importance rises, however, as this group becomes a larger part of the electorate. A study of local voting rights in Belgium and Switzerland found higher social expenditure after those rights were extended, financed initially in part through debt and later through taxes and charges. This is not a law governing all of Europe, but it does demonstrate how a new electorate can bring about different budgetary choices.

At the same time, immigration produces the opposite movement among part of the existing population. A review in the Journal of Economic Literature concludes that immigration often increases support for anti-immigration parties and may reduce support for redistribution and diversity among existing residents. They react to competition for housing, pressure on schools and healthcare, cultural change and the perception that costs are distributed unfairly.

Europe is therefore not simply moving steadily to the left. The political center is being hollowed out from both sides. A younger, urban, and more diverse electorate expects more from government on average. Part of the native working and lower-middle class moves to the right. The shift already underway is principally one of polarization. Over the longer term, however, the growing weight of the second generation may indeed pull economic policy to the left, particularly in the major cities.

The welfare state meets reality

Immigration is often presented as the solution to aging. Yet a young immigrant is not automatically a net contributor. The demographic advantage arises only when he or she works, earns enough, and pays taxes.

According to Eurostat, approximately 65.2 percent of non-EU citizens ages twenty to 64 were employed in 2025, compared with 77 percent of national citizens. Their respective unemployment rates were 12.3 and 5.2 percent. Because this comparison is based on citizenship, naturalized immigrants are counted among national citizens. Unemployment among non-EU citizens has also fallen substantially since 2015. The problem is therefore not that their unemployment must keep rising, but that a large employment gap may persist while the population concerned continues to grow.

This also increases the absolute number of people on low incomes or requiring public support. In 2025, 45.3 percent of adult non-EU citizens were at risk of poverty or social exclusion, compared with 18.2 percent of national citizens. This is not a direct measure of benefit receipt, but it indicates the scale of the social challenge. The Joint Research Centre summarizes the central point well: increasing inflows without improving labor-market integration produces little fiscal benefit; higher labor-force participation can produce substantial gains.

The dividing line therefore does not run simply between natives and immigrants, but between work and non-work, productivity and dependency. An immigrant in employment can strengthen the welfare state. A poorly integrated immigrant is not a solution to the pension problem but an additional budgetary cost. The same is true of anyone born in Europe who remains outside the labor market for a prolonged period.

The pension arithmetic makes the pressure visible. Suppose every person over 65 receives a pension worth half the average earned income. Based on the changing age ratio, the required contribution rises arithmetically from about nineteen percent of wages in 2025 to 27 percent in 2050 and almost 34 percent in 2100. The official 2024 Ageing Report expects the number of contributors per hundred pensioners to fall from 174 to roughly 132. Projected expenditure does not completely spiral out of control because the models already assume a higher retirement age and lower pensions relative to wages.

The housing market will also divide. If average household size remains unchanged, Europe’s housing requirement falls by only about 1.5 percent by 2050. If average household size declines from 2.3 to 2.2 people, demand instead rises by roughly three percent. Migration and younger households are also concentrated in cities. Rents and purchase prices may remain high there while homes in aging rural areas lose value. Europe is likely to face two housing crises at once: scarcity in growing cities and vacancy in shrinking regions.

The middle class pays the bill

When pension, healthcare, education, housing and integration costs rise together, politics has a predictable reflex: redistribute more. Parties promise that the broadest shoulders will carry the heaviest burden. Yet a large welfare state cannot be financed exclusively by a handful of billionaires. Ultimately, the bill reaches the broad working middle and upper-middle class.

It earns too much to qualify for many forms of support, but too little to arrange its income internationally. Its wages are visible, its home can be taxed and its consumption can be tapped through VAT, excise duties and energy levies. The middle class therefore risks becoming the cash cow of a system with more entitlements and relatively fewer productive contributors.

Successful citizens, meanwhile, are not entirely tied to their country of birth. Entrepreneurs, doctors, engineers, and IT professionals can move to another country or region. Research covering 21 European countries shows that the location decisions of the highest-earning ten percent respond measurably to tax differences. The average effect is modest, but stronger among internationally mobile top earners. Scandinavian research confirms that taxation affects the departure of wealthy residents, while also warning that the wider macroeconomic effects are generally small.

A mass exodus is therefore not inevitable. Selective departure may nevertheless trigger a local downward spiral. When young, highly educated families, entrepreneurs and major taxpayers leave, more of the tax base disappears than the population number suggests. Those remaining must pay more for schools, roads, healthcare and municipal services with high fixed costs. The OECD warns of precisely this cycle: a smaller tax base leads to poorer or more expensive services, making a region still less attractive.

Even the official poverty threshold may then fall. Eurostat defines the risk of poverty as an income below sixty percent of the national median. When a broad and productive middle stratum leaves or becomes poorer, the median falls, taking the poverty threshold with it. If median income falls by ten percent, the official threshold also falls by ten percent under an unchanged definition. A society may consequently record the same number of people in poverty even as its actual living standard deteriorates.

A warning, not a destiny

The projections do not prove that Europe will inevitably acquire a Muslim majority or become socialist. They do indicate a larger Muslim share and show that the age structure, origins and political interests within the population are changing profoundly.

Anyone who wishes to stop immigration completely must explain how a much smaller workforce will sustain healthcare, pensions and the economy. Anyone who wishes to use immigration to fill every demographic shortfall must explain how tens of millions of people will be brought into employment and incorporated into a shared European legal and cultural order.

The answer cannot consist solely of higher taxes. Europe needs greater productivity, automation, family-friendly policies, higher labor-force participation, and a more selective migration policy. Integration must be measured by language proficiency, employment, educational results, and respect for democratic constitutional government, not by the number of residence permits issued.

A welfare state can remain generous only when enough people contribute and believe that the system is reciprocal and fair. Europe is not just shrinking. Its population is changing and its politics will change with it. This is not a mathematically predetermined collapse, but it is a warning.

The most dangerous choice is not either decline or immigration in itself. It is to finance uncontrolled demographic change by placing an ever heavier burden on the productive middle class, until the very people who sustain the system decide that they would be better off elsewhere.