A polite reminder: some people predict population dynamics for living.<p>For example, the World Bank: <a href="http://data.worldbank.org/data-catalog/population-projection-tables" rel="nofollow">http://data.worldbank.org/data-catalog/population-projection...</a><p>If you look for dinosaurs, the WB also have a 1984 report on topic: <a href="http://documents.worldbank.org/curated/en/496471468156899142/World-development-report-1984" rel="nofollow">http://documents.worldbank.org/curated/en/496471468156899142...</a> (see p. 186, "Population data supplement")<p>The UN, IMF, and most national agencies also release their numbers.<p>In general, world GDP growth — and its correlates, like HDI — is stable enough to predict population growth. As a country gets richer, fertility falls: women get careers, jobs require more education for children, people start to rely on savings, instead of family. The aggregate numbers are smooth and predictable. At least, for a reasonable time horizon.<p>But you need to fine-tune the model at the right aggregation level. For example, the US, EU, Japan have similar GDP levels, but fertility in the US remains high. Census data helps settle down these issues.
There's no testable prediction in this model.<p>He also just assumes some naive correlations based on some graphs, without doing any rudimentary statistics (e.g. chi squared to check if the correlations are even notable), and then plugs the numbers in and see's what he comes out with.<p>Instead, he should base his model on data from say 2000, and then predict the population in 2015, and then if that's correct, he might be able to say something about 2065 with any degree of certainty.<p>That he disagrees with other predictions suggests his model is wrong, but it's difficult to say how.
The description of this suggests the analysis is a <i>lot</i> less plausible than the actual figure:<p>- Birthrates are assumed to fall linearly all the way to zero, despite an abundance of reasons why that's obviously not likely to be the case<p>- If I'm reading it correctly, countries' birth rate declines are estimated as a discrete property of arbitrary HDI labels rather than a function of actual HDI score. Which in practice means that minor threshold differences decide whether birthrates in a country to fall sharply across one decade and less sharply in another<p>- Small islands are given equal weight to China and India in gauging an HDI-bracket's average birth rate<p>- The HDI brackets aren't even <i>copied</i> correctly, and thus many ultra wealthy territories like Bermuda and Gibraltar are placed in the "low HDI" bracket. That probably means the model massively underestimates the YoY decline in birthrates in low development countries (which I suppose at least works in the opposite direction to incorrect assumptions made about birthrates dropping to zero)<p>- There's really no justification at all for projecting a death rate that varies between ~1 and ~15 per 1000 as a uniform 8 per 1000, especially not when data on population age distributions and life expectancies exists. (The only saving grace is that it isn't that far from the figure for India and China which have a disproportionate effect on the model)
<i>"The table above already shows that birth rates go to zero by 2065."</i><p>Uh.... This seems incorrect. Sure we can extrapolate the declining birthrate all the way down to zero, but realistically it will level out somewhere since humans will never stop producing more humans. Granted it might be a lower birthrate, but never 0.
The author's models for population growth are too rudimentary to be accurate over more than one or two decades. I find it really hard to believe that the growth rate for countries will maintain a constant value for the next few centuries.
Why do almost no population projections take climate change into account? We're rapidly heading towards a much less habitable earth. The projections I've seen with Africa at a population of 3-4 billion people by 2100 would be laughable if the whole situation wasn't so damn tragic.
<a href="https://en.wikipedia.org/wiki/The_Limits_to_Growth" rel="nofollow">https://en.wikipedia.org/wiki/The_Limits_to_Growth</a><p>not sure if there's anything more to say.
Is this such a bad thing. Third world countries are becoming westernized giving us a continued growth of our markets even though the population might shrink.<p>Automation might make manual labor a thing of the past. We might not have enough jobs or natural resources to support a growing population.<p>Sadly I feel like studies like this don't take into consideration what a ww3 might do on the world's population long term. We are in an unprecedented time of peace which might not last to 2065.
Can someone enlighten me how did he end up prediction extinction by 2300? I see words, but it makes no sense to me.<p>Even if it correctly peaks at 2065, even if it declines, it should stop at a stable level since most developed nations usually have 1-2 child per family today. I cannot imagine the next generations doing nothing with a laid back attitude and slowly let us die out because nobody wants to make babies :)
Even if you stay within your own solar system, a civilization only slightly advanced from our own, even without fusion power, could easily sustain a population of a trillion.<p><a href="https://www.youtube.com/watch?v=aDqjK5vR6hE" rel="nofollow">https://www.youtube.com/watch?v=aDqjK5vR6hE</a>
Does he take into account that population growth has been mostly hyperbolic?<p>Hyperbolic Growth of the World Population in the Past 12,000 Years: <a href="https://arxiv.org/pdf/1510.00992" rel="nofollow">https://arxiv.org/pdf/1510.00992</a>
It will be interesting if the increase in automation and decrease in working hours that we're likely to see in the future will lead to a reverse in the declining birth trends that we've seen in high HDI countries.
Great video: <a href="https://www.gapminder.org/videos/dont-panic-the-facts-about-population/" rel="nofollow">https://www.gapminder.org/videos/dont-panic-the-facts-about-...</a>
This assumes uniform gene pools that never change. In other words, it denies evolution.<p>For each nation, he extrapolates various existing trends. This wouldn't be too bad if people within each nation were uniform. They are not. Given the choice between having children and having other luxury, people do not all make the same decision. The mental traits that influence this decision are inheritable, both genetically (brain structure and chemistry) and culturally (religion and more). It should be obvious that the portion of people who decide to have kids will increase. We'll be back to exponential growth until we hit real resource limits and start dying in squalor.<p>This is unavoidable. Anything done to stop it will be overcome, because those best at overcoming impediments to reproduction will come to dominate the gene pool.