For more than three decades, climate policy has been built on a central premise: that rising populations and expanding economies would inevitably drive ever-increasing pressure on the planet.

On May 5, 2026, without fanfare, the Intergovernmental Panel on Climate Change (IPCC) made a significant announcement: its most dire climate scenario, RCP 8.5, is now classified as “unlikely.” For nearly 15 years, this scenario fueled tens of thousands of articles, entire TV talk shows, and the eco-anxiety of an entire generation. It was the raw material for the +5°C projections that were brandished to justify ever more restrictions, taxes, and bans. Today, the IPCC tacitly acknowledges that it will not come to pass. Some commentators welcome this. Others, more discreetly, explain that it was never anything more than an “intellectual exercise.” A curious exercise, whose conclusions shaped 30 years of public policy.

13 Billion people

Media outlets celebrate this abandonment but carefully fail to mention that RCP 8.5 was based on the assumption of a global population of 13 billion people. The scenario was far-fetched not just for the past few years, but from day one. Demographers knew it. Successive United Nations reports were already pointing to a very different trajectory. But once fear had taken hold, no one wanted to check the math anymore.

For more than three decades, climate policy — and not only model RCP 8.5 — has been built on a central premise: that rising populations and expanding economies would inevitably drive ever-increasing pressure on the planet. This assumption, embedded in global frameworks since the 1992 Rio Climate Convention, continues to shape policy today.

But the world that gave rise to that assumption no longer exists.

One of us, an international industrialist and investor in the electronics sector, chose two decades ago to invest — out of conviction — in wind and solar power to help reduce greenhouse gas emissions. Like many at the time, he believed a profound transformation of energy systems was both necessary and urgent. Renewable energy has since secured a place in Europe’s electricity mix.

That progress is real. But it is only part of the story — and not the most important one.

The defining change of our era is not technological. It is demographic.

In 1990, the internet did not yet exist. Today, widespread access to information has reshaped societies, empowering individuals — and especially women — to make informed life choices. One consequence has been largely overlooked: a rapid and global decline in child per woman.

Across the developed world, birth rates have fallen well below replacement levels. The same trend is now evident in emerging economies. India has crossed that threshold. The United States is following a similar path. Even in Africa, where fertility remains higher, the downward trend has begun and is likely to continue as economic development advances.

The implications are profound. If global fertility stabilizes around 1.5 children per woman by mid-century, the world’s population will peak at roughly 8.5 billion before declining. At 1.3, it could fall to around four billion by 2100 — half the level once expected. This stands in stark contrast to earlier projections that assumed continued growth toward 10 billion or 13 billion (RCP 8.5 model).

Kaya equation

To understand why this matters for climate policy, consider a simple identity. According to the so-called Kaya equation, carbon emissions are the product of four factors: population, economic output per person, the amount of energy required to produce that output, and the carbon intensity of that energy. For decades, policy has focused on the latter two — improving efficiency and reducing carbon intensity.

But population is the first term in that equation — and the only one now undergoing a structural, global reversal.

Importantly, this shift is not the result of coercive policy, and it is right to be so. It reflects voluntary choices, driven by education, economic opportunity, and access to information. It is both peaceful and self-reinforcing. And it operates on a scale large enough to reshape long-term emissions trajectories.

Let’s be clear: we do not advocate for a declining birth rate. We may personally regret this decline in fertility — and the drop in the birth rate poses considerable challenges to our societies in terms of pensions, the transmission of traditions, and the vitality of our civilization. None of this suggests that environmental challenges should be dismissed. Technological progress and regulation have already improved air quality and living conditions in many parts of the world. These gains should continue.

Biased

But it does suggest that current policy frameworks are biased. The assumption of ever-expanding human pressure on the planet no longer holds. The world is entering a phase not of unchecked growth, but of gradual demographic contraction.

This changes the calculus.

The idea that economic activity must be sharply curtailed to address climate risks rests on outdated premises. A more accurate view recognizes that prosperity itself — particularly education and individual empowerment — is a powerful driver of both demographic stabilization and environmental improvement.

Climate policy should adapt accordingly.

The world has changed. It is time our thinking caught up.