Global population estimates tend to be imprecise. I will wait for official sources like the UN Population devision or similar to publish figures to resolve the market.
I will consider the population to have peaked if it is estimated to be more than 0.1% below the previous year and the drop is not attributable to a specific non recurring world event.
Resolution criteria
This market will resolve to "YES" if the global population peaks in a specific year, based on data published by the United Nations Population Division (UNPD). A peak is defined as the year after which the total global population begins a sustained decline, where the population in subsequent years is estimated to be at least 0.1% lower than the peak year.
To resolve this market, the decline must not be attributable to a single, non-recurring catastrophic event (such as a major war, pandemic, or natural disaster) that causes a temporary drop followed by a resumption of population growth. The UNPD's World Population Prospects (available at https://population.un.org/wpp/) will serve as the primary source of truth. If the UNPD revises its historical or future projections, the most recent data available at the time of resolution will be used.
Background
Estimating the timing of a global population peak is subject to significant uncertainty, as it relies on complex models of fertility rates, life expectancy, and migration patterns. Different organizations often provide varying projections; for instance, the UNPD, the Institute for Health Metrics and Evaluation (IHME), and other demographic research groups frequently update their forecasts based on new socioeconomic data. As of current projections, many models anticipate the global population to peak sometime in the late 21st century, though estimates vary widely regarding the exact year and the total number of people at that peak.
1,000People are also trading
The disappearance of multiple rivers or lakes is an interesting edge case.
@AlanTennant not sure if this was a way to see if it was an AI-managed market. Just in case, I tried to pretend and asked Qwen3.6 to come up with a fun reaction to your comment but I can't say it's good. Here you go anyway.
"Noted! I'll add "hydrographic collapse" to the UNPD's demographic checklist right next to "fertility rates" and "unpredictable migration patterns." Until they release the World Population & Lake Prospects, I'll keep my resolution charts focused on people, not puddles. 🌊📊✨"
@figo It's a real problem around the world, including the USA, mostly due to overuse of the water for agriculture and cities. One of Americas large rivers that originates in the middle of the country no longer reaches the sea because of this very problem, and it provides for a whole city there. Russia managed to completely destroy the world's 4 largest inland body of water some years ago, it didn't take long to go from there to almost entirely gone. When a river or lake people need disappears quickly it can also result in sudden international emigration events, sometimes mostly by foot. The more developed a country the less I would the disappearance of a body of water to have an effect as dramatic as the last example, but it will likely affect the carrying capacity to some extent. There's been at least one case of deforestation loosening soil and leading to a temporary river forming rapidly, that emptied a lake into another quite some way away, and the original lake not recovering.
This key part is, that humans rapidly ramp up this sort of disruptive activity over time. We are able to plan properly and act sensibly, but higher tech, more and larger machinery, and enormously higher populations that can grow faster than linearly means that there may be a big spike of this sort disruption in the future, just as we now disrupt more than we could have centuries ago.
@AlanTennant Thanks for the clarification! I had missed one or two steps of your reasoning so sorry for taking it as a joke. Not sure how to factor that in in my mental model because population is mostly driven by fertility today but food collapse is a big thing medium-long term for sure.