I have a seven-month-old grandson. I haven’t enjoyed a little human being this much in a long time.

I dedicated my book The Only Possible Solution to the little guy, who has absolutely no idea what is hanging over his head. But if things work out reasonably well for the planet, there is a pretty good chance he will still be alive in 2125. People are living longer and longer.

But fewer and fewer children are being born.

My grandfather had twelve grandchildren. My father—if he were still alive—would have had seven. I’m down to just three.

So the number keeps falling. And that’s exactly what the statistics show.

New population figures published by Eurostat last month confirm it. The EU still grew by 706,000 people in 2025, to 452 million, but only because of migration. Without migration, the population would already be shrinking. Since 2012, more people have died in the EU than have been born.

And that is usually presented as bad news.

I think it’s good news.

There are now more than eight billion of us on this planet. Billions of people don’t have access to enough nutritious food. We fight over water, energy, resources, and land. And every year, we use more of the Earth’s resources than it can replenish.

Europe’s fertility rate has now fallen to an average of 1.34 children per woman. In 1964, it was still 2.62. That’s well below the level needed to maintain the population without migration.

When I interviewed and researched one hundred Bright Minds for The Only Possible Solution, this question came up too: how many people can the Earth actually support sustainably? Some of them arrived at a figure of not much more than two billion—depending on how we live, what we consume, and how much space we are willing to leave to nature.

That’s quite a difference from the more than eight billion people walking around today.

According to Eurostat, the EU population will continue to grow for a little while, reaching about 453 million in 2029. Then the decline begins. By 2100, there are expected to be about 399 million Europeans.

Economists worry about this. Who will do the work? Who will pay the pensions? Who will take care of all those elderly people?

But perhaps we’re asking the wrong questions.

Those questions assume the economy of 2026. An economy in which people work five days a week, increasing production requires increasing amounts of human labor, and economic growth requires ever more consumers. They also assume a society in which immigration is seen as a major threat and a great evil, even though foreign workers are already indispensable to our economies.

By 2125, things could look very different.

Robots and AI will do much of the work. People will not only live longer but remain healthy for longer. And fewer people will mean less pressure on housing, farmland, water, nature, and energy. The countries people are fleeing today may by then have achieved a decent level of prosperity themselves.

My grandson may be 99 in 2125.

I hope he looks back at 2026 and is amazed.

Not because we were having too few children.

But because we thought that was a problem.

Back From The Future #48 is part of a series exploring how the world of 2125 may have solved the greatest challenges of our time.