48 million people, and two very different futures

Spain is home to about 47.9 million people in 2026 by the UN’s count, around 6.4% of Europe’s population and about 32nd in the world¹. What happens next depends on whose numbers you trust.

On the UN’s medium projection, Spain has already peaked. Its population topped out at about 47.9 million in 2024 and falls to 45.0 million by 2050¹. Spain’s own statistics institute, INE, sees the opposite. It already counts 49.6 million residents in 2026, and projects about 54.6 million by 2050². By mid-century the two are 9.5 million people apart, roughly a fifth of Spain’s population today.

Almost no babies, and a lot of newcomers

The split comes down to migration, because Spain’s own births can’t sustain the population. Spanish women had just 1.10 children on average in 2024, according to INE², barely half the 2.1 needed to hold a population steady. The median age is about 46¹.

People also live a long time. Life expectancy at birth was 84.0 years in 2024, the highest in the EU³. Long lives and few births make for an older country, and without newcomers a shrinking one. INE’s own test case with no migration at all has the population falling to about 31.7 million².

Instead, people keep arriving. In 2024 about 1.29 million people moved to Spain and 662,000 left, a net gain of 626,268 in a single year². INE says its projected growth comes exclusively from international migration². The UN, writing in 2024, assumed much less of it, which is how it ends up with a shrinking Spain.

Forty-eight million people on 13% of the land

Spain’s people are crowded into a surprisingly small part of the country. Only 13% of its square-kilometre grid cells have anyone living in them, the lowest share in the EU. In France the figure is 68%, in Germany 60%, in Italy 57% and even in Portugal 47%⁷.

Where people do live, they live close together. Inhabited areas average 737 people per square kilometre, the second-highest density among inhabited areas anywhere in the EU⁷. So Spain is two countries at once: busy coasts and a packed Madrid, and a vast interior of emptied villages that Spaniards call la España vaciada, “emptied Spain”.

A country running short of water

That interior is also drying out. Desertification already affects around 74% of Spain’s territory, summers run nearly five weeks longer than in the 1980s, and more than 80% of people regularly face extreme heat⁴.

Nearly two-thirds of Spain has a Mediterranean climate, with hot, dry summers. About half of all the water available is already taken for use, and in some coastal basins the share reaches around 90%⁵.

The clearest sign is Doñana, the great wetland near the mouth of the Guadalquivir River in the southwest. Years of over-pumping have drained the groundwater that feeds it.

A wet winter can refill a reservoir in a few months, but an aquifer pumped down over decades takes far longer to recover. More people, mostly on the coasts, will need more water from those same stretched basins. The wider picture is in the global desertification rate.

2.14 Earths, and most of it from elsewhere

If everyone in the world lived like the average person in Spain, humanity would need 2.14 Earths⁹. Each Spaniard uses about 3.21 global hectares a year, while Spain’s own land renews just 1.23, so the country uses more than two and a half times what its ecosystems produce⁹.

Carbon is the biggest slice, 1.04 Earths, the forest needed to absorb the carbon dioxide from the oil and gas Spain burns. Cropland adds 0.53, and fishing grounds 0.27, the fish Spain catches and eats⁹.

More than half of Spain’s electricity is now renewable

Spain’s sun and wind are turning into a real advantage. Renewables produced 55.5% of its electricity in 2025, rising to 56.6% once rooftop panels feeding their owners are counted⁸. Only Germany generates more electricity from wind and solar combined among the countries in Europe’s shared grid⁸.

That cuts into the carbon slice of the footprint, the biggest one. It doesn’t help with water, though, which turns on how much is pumped from Spain’s rivers and aquifers.

Where Spain is heading

By 2050 Spain will have somewhere between 45 and 55 million people, and the deciding factor is almost entirely migration. If recent arrivals continue, INE’s growing Spain looks more likely than the UN’s shrinking one; if they slow sharply, the country starts to shrink and age fast.

Either way, more of those people will live on the coasts and in the cities, where the water is already most stretched. That suggests sharing water will be Spain’s hardest choice by 2050.