We might have less time than we thought, but don't panic just yet. A popular mathematical theory suggests humanity has about 17,100 years left before it reaches its end. The estimate comes from the so-called 'Doomsday Argument', a statistical idea first proposed in 1983. The theory doesn't predict exactly what event will wipe out humanity, only when the maths suggests our species might reach its end.
The Doomsday Argument uses a person's position in the sequence of humans who have ever lived as a statistical clue about the future. Researchers begin with an estimate that around 117 billion people have lived throughout human history. They then assume there is a 95% chance we are not among the first 5% of all humans who will ever exist.
This calculation suggests that the total number of humans who will ever be born is unlikely to be in excess of around 2.34 trillion. At today's birth rates, that total would be reached roughly 17,100 years from now. However, the calculation is not a prediction that humanity will definitely disappear at that point, but rather a warning about the limits of assuming our species will continue indefinitely.
The maths doesn't attempt to explain what might wipe us out, but potential risks include things like nuclear war, climate change, pandemics, asteroid impacts, artificial intelligence, and other global catastrophes. Critics argue that humanity's future population isn't random and could be heavily influenced by factors such as falling birth rates, medical advances, economic changes, and technological development.
Some researchers point out that future threats may come from technologies or events that don't even exist yet, making them impossible to predict currently. The Doomsday Argument has remained controversial since its introduction, with many experts rejecting it due to its uncertain assumptions.
Supporters describe the theory as a mathematical exercise, while critics reject its assumptions entirely. Another criticism is that the argument doesn't account for the possibility of humans expanding beyond Earth, which could change the scenario imagined by the theory. Even researchers who support the idea generally describe it as a statistical argument rather than an actual forecast.
The study is not alone in examining the possible future of the human population. A more recent study published in August 2025 gives us a little more than 300 years before we say goodbye. Whether the Doomsday Argument proves useful as a way of thinking about humanity's future remains debated. For now, it is best viewed as an intriguing piece of probability theory rather than a warning that civilisation has a set expiry date.
