Earth's population could plummet by 2064

The work was published in the journal Chaos, Solitons & Fractals.

The authors used a non-linear mathematical model that they say describes different population growth regimes over the past 12,000 years - from slow growth in antiquity to rapid population growth in the industrial era.

The most high-profile part of the study is the crisis scenario. If global environmental, resource, military or pandemic shocks drastically reduce the planet's "carrying capacity" to about 2bn people, the model shows the possibility of a rapid population decline, up to about halving by 2064. The authors themselves emphasise: this is an illustrative scenario, not a baseline projection of the future.

Details

The model is based on the idea of non-linear dynamics. To put it simply, the population grows or declines not in a straight line, but can change its mode abruptly: it increases smoothly for a long time, then accelerates, slows down or, under strong external constraints, goes into a rapid decline.

The authors compared their formula with historical population data over a very long period of about 12,000 years. They argue that the same equation can describe different epochs: slow growth after the Neolithic period, a sharp acceleration in recent centuries, and a calmer regime after the 1970s, when fertility began to decline in many countries.

The main idea of the crisis scenario is the following: if the planet, due to a combination of crises, can sustainably support not the current 8+ billion people, but roughly 2 billion, the system may react not with a smooth decline, but with a sharp decline. In such a model, the population could decline very quickly - within a few decades.

But this is not a mainstream demographic forecast. It is more of a stress test: "what happens if conditions deteriorate sharply".

Why it matters

Such models are not needed to scare the date "2064". Their purpose is to show how sensitive human populations can be to big changes: climate crisis, resource scarcity, wars, pandemics, destruction of infrastructure, or a sharp decline in available energy and food.

That said, it is important to compare this work with more familiar population projections. For example, the UN in World Population Prospects 2024 expects the world's population to continue to grow for another 50-60 years or so, to peak at around 10.3bn in the mid-2080s, and then start to decline slightly. That's a very different scenario - without a sharp global collapse by 2064.

In other words, the new model doesn't overturn the UN projections. It shows what an extreme scenario might look like if the world system faces a sharp drop in available resources and living conditions.

Background

The idea of mathematically describing population growth is not new. In the 20th century, there have already been "end-of-the-world scenarios" where human population growth was extrapolated to absurdly high values. The most famous example is the calculation of Heinz von Foerster and colleagues, who in the 1960s assumed a mathematical "singularity" of population around 2026. That didn't happen because birth rates in many countries began to decline.

The new paper returns to a similar theme, but from a different angle. The authors believe that population growth cannot be described only by a simple exponent or a classical logistic curve. They propose a more flexible equation that can show different regimes - growth, stabilisation or sharp decline.

The main conclusion is simple: the date 2064 in this paper is not the "designated year of catastrophe", but the result of a calculation in a rigid scenario. The real future will depend on fertility, mortality, migration, politics, climate, medicine, technology, food and the ability of countries to mitigate the risks of major crises.

Source

Alessio Zaccone, Kostya Trachenko, "Global population crisis scenarios predicted by a general nonlinear dynamical model", Chaos, Solitons & Fractals, 2026.