Heinz von Foerster's tongue-in-cheek forecast tracked world population surprisingly well until the 1990s, when falling birth rates broke the curve. Here is what the math got right, where it failed, and why there is nothing to fear next month.

Less than four weeks from now, the date set for the end of humanity by a peer-reviewed paper will arrive and pass without incident. On Nov. 4, 1960, the journal Science published "Doomsday: Friday, 13 November, A.D. 2026," which concluded that world population would race toward infinity on that date.

There is no real threat on Nov. 13 — but the story is worth telling anyway, because the equation behind the headline beat most professional forecasts for about 30 years before reality pulled away from it.

For readers, the lesson is practical. Population projections shape long-term planning for water, food, energy and emissions, and this old forecast shows how a model can look reliable right up until the conditions behind it change.

A Joke Built on Serious Math

The paper's lead author was Heinz von Foerster, an Austrian-American physicist and pioneer of cybernetics, writing with his students Patricia M. Mora and Lawrence W. Amiot. They fit a curve to 24 estimates of world population spanning the previous 2,000 years, historian Alan MacEachern of Western University explains in The Conversation.

The authors' conclusion was blunt — our descendants would not starve, they wrote; "They will be squeezed to death," as ScienceDaily's republication of MacEachern's essay recounts. Their proposed remedy was to cut the global birth rate roughly in half.

Mathematicians and demographers attacked the paper in letters to Science, calling it absurd. The authors stood by their math and answered the critics in print, keeping the exchange going for years. Yet its projections were better than those of most demographers through the 1970s and 1980s. The work was cited in textbooks, before a Canadian parliamentary committee in 1963 and in a 1971 U.S. Supreme Court abortion case.

The Curve That Races to Infinity

Most people know exponential growth, where a population doubles over a steady interval. Von Foerster's curve was faster. In hyperbolic growth, each doubling takes less time than the last, so the line bends upward until it reaches a vertical wall at a specific date.

The idea behind it was that more people produce more cooperation and innovation, which allows even faster growth. The model put that wall on Nov. 13, 2026, give or take about five years, Popular Science reported.

Even the authors' own error window was wide. Give or take five years means the model allowed for a blowup anywhere from roughly 2021 to 2031, a range that now has only a few years left in it.

For centuries of data, that feedback loop fit remarkably well. Mathematical biologist Joel Cohen of Rockefeller University and Columbia University summed up the paradox to Popular Science: "He got the picture right just as that picture ceased to be right."

Economic demographer Dean Spears of the University of Texas told the magazine that the core assumption rested on a misunderstanding of where population growth actually comes from. Growth depends on how many children families choose to have, not simply on how many people already exist.

Falling Birth Rates Broke the Model

Around 1993, world population began falling behind the doomsday curve, and the gap has widened since. MacEachern attributes the break to the world doing roughly what the authors recommended: the global birth rate today is slightly less than half its 1960 level.

Instead of approaching infinity, the world now holds about 8.3 billion people, according to United Nations data cited by Popular Science. The UN's 2024 World Population Prospects projected that global population will peak at about 10.3 billion in the mid-2080s before slowly declining.

That shift matters for environmental planning. A peak and decline point to a different future for farmland, water demand and emissions than an ever-steepening curve would, though the total still rises for decades and its regional distribution is uneven.

Population assumptions sit underneath many long-range environmental studies, from estimates of future food and water demand to the scenarios climate researchers use to explore possible emissions paths. When those assumptions shift, the projected pressures on land, rivers and the atmosphere shift with them.

Reading Population Models Wisely

The von Foerster paper is not evidence that forecasting is useless. It shows that a model built from past trends can fit the data well and still fail when the underlying behavior changes, here, the number of children people choose to have.

Modern projections, including the UN's, are built differently. They model births, deaths, and migration by age and country and publish a range of outcomes rather than a single date. They can still miss, especially decades out, which is why they are revised every few years.

MacEachern draws a broader takeaway in his essay: "For me, the lesson is in how we present our beliefs to the world."A confident headline date made the paper memorable, but the uncertainty behind it was the more important scientific message.

Readers who see social media posts warning about Nov. 13 can safely ignore them. Nothing in the 1960 paper, or in current data, points to any physical event on that date.

The bottom line: Friday, Nov. 13, will be an ordinary day. The real story is how a simple equation tracked human growth for generations, and how changes in family size rewrote humanity's trajectory faster than the math could predict.

What Readers Want to Know

Is the world going to end on Nov. 13, 2026?

No. The date comes from a 1960 mathematical model, and there is no scientific evidence of any threat on that day.

Who made the prediction?

Physicist Heinz von Foerster and his students Patricia M. Mora and Lawrence W. Amiot, in a paper published in Science on Nov. 4, 1960.

What is hyperbolic growth?

It is growth in which each doubling happens faster than the last, so the curve reaches an infinite value at a specific date.

Was the forecast ever accurate?

Yes. It outperformed most demographers' projections through the 1970s and 1980s, before falling behind actual population around 1993.

Why did it stop working?

Birth rates fell. The global birth rate is now slightly less than half its 1960 level.

What do current projections show?

The UN's 2024 projections show world population peaking at about 10.3 billion in the mid-2080s.