Transcription
So let's start today's video with this beautiful map. The map showing world population in 2018. But what makes this map really interesting is that here each of the squares represents half a million people. And so in this case, the size of the country is directly proportional to the total population. Which is why countries like Russia are so ridiculously tiny compared to their actual physical size.
But the reason I wanted to start with the map is because, well, today, as you can probably tell from the title, we're going to be discussing the extinction event. Um, okay. We're going to be discussing this particular study that was just released a few days ago on the human extinction based on the changes in demographics around the planet, or essentially a kind of a hypothetical expiration date for the entire human species. And so this recent study, or technically this non-peer-reviewed paper, started to make headlines because of an extremely precise and very dramatic forecast. According to this research, we only have 314 years left, and the current population is assumed to be about 8.1 billion people. According to the study, by the year 2339, the number will be zero. Humanity will be extinct.
And so let's discuss this somewhat bizarre proposition in a bit more detail. Let's look closely at the scientific claims behind this and compare this to some of the more established predictions by various agencies. So here we're going to break down exactly what the authors discovered and how they discovered this, and what this tells us about future population trends. But I guess let's start with who wrote this and why they wrote this. And so here, this was written by actual demographers David Swanson and Jeff Tamman. And when they presented the study, according to their critics, it actually might have been to basically kind of maybe trap the press or bait unwary scientific journalists into some kind of a credulous doom coverage. So basically, they were trying to make it go viral. But despite of this, the core mathematical structure they used does provide us with a very fascinating case study on how sometimes small assumptions can actually lead to very extreme and very incorrect results. And so, just so that we are clear, it's extremely unlikely that we are actually going to go extinct anytime soon. But let's discuss the science first.
And here, I think it's important to start with methodology. How exactly was this achieved and what tools were used? And here, researchers used advanced established mathematical tools normally utilized in population studies, such as what's known as the cohort component method (CCM) and the Hamilton Perry method. CCM is a type of projection technique that forecasts future population changes by using components of change such as fertility, migration, and mortality in order to predict future population size and age distribution. And it often produces something that kind of looks like this, or your typical population graph. And so normally, by using this method, scientists can predict where a society is headed. Likewise, the Hamilton Perry method projects future population based on two successive census counts and specifically by trying to assess how the population changed within a short period of time. And so normally, this requires much less data, but obviously does not always produce accurate results. And well, normally when scientists use very similar tools, they basically end up with something like this, an extremely wide range of predictions for where the population is headed. And that's because it's actually very difficult to predict.
And so the problem isn't really the tools, it's the specific input that's usually fed into the tools. And so in this particular case, in this study, the entire extinction idea depends on one key piece of recent data. It essentially only uses points from between 2019 and 2024 and then tries to extrapolate this, assuming that this is going to be the future of humanity. Now, here's what I mean. So during this period, the researchers, when looking at something called the child-adult ratio, also known as CAR, the method that usually measures fertility rate, discovered that the ratio dropped by approximately 7.5%. In other words, they discovered that the fertility between 2019 and 2024 decreased by over 7%, which, as you probably know, would not be surprising. We've heard a lot of different stories about fertility rates going down for several years. But you might also know that something else happened around this time that's actually kind of ignored, possibly on purpose, just to, I guess, make a point in terms of data. And so possibly something else affected the fertility rates. But in this case, we're just looking at the numbers. But in reality, though, fertility rates during a global crisis or a major social upheaval are very often unusual. And so in demographic studies, these types of periods usually provide very unstable and somewhat inaccurate data. So technically, this should not be used for long-term prediction. But that was the foundation for this particular study.
And so the assumption here is that this dramatic 7.5% drop in fertility is going to continue indefinitely, basically repeating every 5 years. And that's kind of what you see in this particular data. And when they plug this consistently steep decline into their projection model, the results become catastrophic. By the year 2139, which is 115 years from when I'm making this video, the world population drops to about 1.5 to maybe 1.8 billion people. By 2239, it's less than 6 million people. And by 2339, it's just cats. Cats everywhere, but basically, yeah, zero people. And so, the mathematical progression is dramatic and very unforgiving, with the authors themselves also noting the dramatic shifts in age structure. And so here we're talking about one of these population pyramids you might have seen before. And in their study, by 2284, nobody in the world would be under the age of 20. And over 90% of the population would be over 65 years old. Now, this might sound extreme, but the thing is, in countries like Japan and South Korea, this is actually slowly becoming a reality. As a matter of fact, Japan right now is slowly becoming a kind of a case study for what might happen in a society where the aging population takes over and the youth basically slowly disappears.
But obviously, this is not really good science. While the prediction in this case is attention-grabbing, this methodology is of course not correct for one simple reason: extrapolation. You cannot extrapolate a pattern observed over a short, unusual 5-year period and then apply it for the next three centuries. So, for example, if we do something similar for the period right after the Second World War, the assumption would be that the population on Earth should be in the hundreds of billions within just the next few years. And so the scientists who made this dramatic forecast, either on purpose or by accident, failed to acknowledge the inevitable uncertainties involved in stretching a snapshot far into the future.
And here, it's important to look at why this type of extreme forecast ignores the realities of population dynamics, even though it uses legitimate analysis tools. The first obvious one is, of course, context. 2019 to 2024 was heavily influenced by major global events. But when it comes to demographics and forecasting population growth, it actually works best during very stable times or when factors influencing various variables, such as, for example, birth rate, don't change too much over time. And so trying to isolate a temporary dip is essentially what completely invalidates this particular conclusion. Likewise, there's also something referred to as the black swan problem. Usually, forecasts must account for highly improbable, high-impact events that we usually refer to as black swans. Conversely, the authors list many other extinction-level events like asteroid strikes, plagues, nuclear wars, or climate change, but argue that a continuous drop in birth rates actually gets us to the same point, just much sooner. And for sociologists studying demographics and population growth, that's once again not a correct approach.
And so, this paper seems to lean heavily on sophisticated terminology and well-known established statistical methods, and then either on purpose or possibly just to go viral, creates a critical flaw in the core assumption and leads to an extremely skewed data with that final date being 2339. And so, yeah, just so that we're clear, the science in this particular paper is very, very bad. The only problem is that I don't know if it's on purpose or basically as a kind of a joke, or if the scientists behind the study actually meant it. I mean, this would make sense if this was April 1st, but this was released right before Halloween, so maybe this was just to scare us. I don't know.
But I guess to understand why this prediction seems to be kind of unrealistic and why practically no one thinks that in 314 years humans won't exist anymore, we possibly should look at some other predictions from other organizations such as the United Nations and, of course, other research institutes. Although here, just for fun, I wanted to actually start with this. This is a human population graph from right after the end of the last glaciation period to now. And look at this ridiculous exponential growth. And just as a side note, the ridiculous growth right at the end can be directly attributed to some of the major advances in medicine and the invention of things like vaccines. As a matter of fact, there is a direct correlation between vaccination periods and dramatic reduction in mortality on the planet in just the last 200 years. So if you know any antivaxxers, maybe show them this graph.
But in general, when trying to figure out the population growth, many of these groups also use very similar sophisticated models, but also rely on changing assumptions in regards to fertility, mortality, life expectancy, and a lot of other things. Which is why right now it's sort of unclear where the population growth is going to go. But the consensus is that we're not facing any imminent extinction anytime soon. The population is still growing, but that rate of growth is indeed decreasing. Not by 7.5% like in that particular study, but decreasing nevertheless. And intriguingly, the peak rate for world population growth happened back in 1963. Here, the growth was 2.2% every year. But as you can see from this graph, every year after this, the rate has been quite consistently declining. And so it was actually estimated at 1.1% around 2017. But importantly, when we look at the overall population growth since the Second World War, pretty much most of the reasons are attributed to major medical advances, although at the same time, we also had a dramatic increase in agricultural production. So here, less sick people and more food allowed the population to grow really fast. And so technically, when looking at the future, most of the organizations today do agree that population is going to peak at some point, but definitely not go extinct in the next 300 years.
So, for example, the UN projection suggests a peak of approximately 10.3 billion people around the year 2080. But after this, the population might start decreasing. And interestingly, the UN also knows that in the long term, it's the total fertility rate that's probably going to decrease population the most. Now, currently, the fertility rate is 2.25, which is why the population is still growing just a little bit, but it is decreasing over time. And different agencies such as the Institute for Health Metrics and Evaluation predict something that's even lower. Here, the peak might be 9.7 billion around 2064, with population declining below 9 billion by the year 2100. And so pretty much most of these mainstream models today show very similar results: the eventual peak and then the eventual decline, with the falling birth rates very likely being the main culprit. But it's not going to be sudden and dramatic like in this study. As a matter of fact, none of these predictions even establish the final year.
But interestingly, both this study and a lot of these other predictions basically settle on the same point: the rate of fertility. And so here, based on what we know about many developed countries and even some of the emerging economies, the fertility rate has been dropping dramatically, even below the so-called replacement levels. With Japan being the first to reach this back in 2005, this was the first year Japan saw the population decline. But at the same time, the rapid population increase in regions like sub-Saharan Africa and some of the less developed countries is why the global growth continues today and basically suggests a kind of a worldwide demographic transition. Although obviously, this doesn't apply to all countries. For example, as we're going to be discussing in a different video, countries like India, that are technically still emerging and developing, have also seen a dramatic shift in population growth and an extreme decrease in fertility. And so technically, the fertility rate is going down everywhere.
But this study that claims the extinction by 2339 is an excellent example of how the presentation of extreme conclusions supported by somewhat selective data and also sophisticated methods can indeed lead us to conclusions that might sound scientifically correct but are actually completely wrong. And so here, based on what we know about other studies, the foundations for this particular prediction are almost certainly incorrect. And so in reality, the complex future of humanity and the population growth is mostly going to be guided by more gradual social and economic factors, and not by some kind of an extreme extrapolation based on one single event. And so based on some of the most accurate projections, we know that moving forward, there might be a much slower growth and possibly a multi-century declining population, but it's extremely unlikely to be a sudden crash and a sudden disappearance of a species, which is a really important reminder that you shouldn't always read just the title and just the headline of the paper, but to always question the assumptions and try to figure out how the conclusion was actually reached.
But we'll definitely come back and discuss this idea a little bit more in some of the future videos because it is a pretty fascinating topic. On that note, thank you for watching. Check out some of the previous videos on a similar topic in the description below. Come back tomorrow to learn something else. Support this channel on Patreon where you can find additional videos, videos without any ads, and can DM me directly, or by joining the channel membership that grants you early access. You can also support the channel by buying the "Wonderful Person" t-shirt in the description below. Stay wonderful. I'll see you tomorrow and as always, bye-bye.
[Music]
[Music]
[Music]
[Music]