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Comment by mupra | Hacker News Reader

A hockey stick is the initial part of an S-curve. A point to consider is that all complex systems are functions of multiple variables and more often than not, non-linear. A complete view of the past and the present is not a guarantee of the future. At best, it can be a guide for having cautious behavior.

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(It's a day ending in y, so here I go again...)

It depends on the sign of the exponent. Negative exponential growth, as we see in wild animal populations, is not guaranteed to turn into an S-curve. As the passenger pigeon would attest, were any of them left.

Meanwhile, to consider a positive exponent case, there's a real question of what will actually cause the bend in the curve of human population. Will it be getting our collective shit together and slowing down? Or will it be a massive die-off after we've destroyed the ecosystems we depend on for things like air to breathe and water to grow our crops?

> It depends on the sign of the exponent. Negative exponential growth, as we see in wild animal populations, is not guaranteed to turn into an S-curve. As the passenger pigeon would attest, were any of them left.

Sigmoid functions are defined over real input values (not integers). If you were to model the decline in (integer) numbers of passenger pigeons with reals, you would get a sigmoid function were the number at the end approximates, but never reaches zero.

What are you trying to achieve by pointing out one of the ways to construct an incorrect model of the passenger pigeon population?

a) I did not construct the model.

b) Using real numbers to reason about integer base values is not wrong per se. You just need to know how to interpret the result.

Did we "get our shit together" in all the rich countries on the planet, which are barely at replacement levels? Did we hit a massive die-off level by overexploiting our resources?

No. We got rich and having kids was less economically valuable (in fact it becomes a cost in rich societies). The Elon Musks of the world are now more concerned about lack of growth than the opposite.

Who knows if Elon is right or you, but it's not as trivial as it seems to predict whether we will ever hit the carrying capacity of the planet.

"The crisis now unfolding, however, is entirely different to the 1970s in one crucial respect… The 1970s crisis was largely artificial. When all is said and done, the oil shock was nothing more than the emerging OPEC cartel asserting its newfound leverage following the peak of continental US oil production. There was no shortage of oil any more than the three-day-week had been caused by coal shortages. What they did, perhaps, give us a glimpse of was what might happen in the event that our economies depleted our fossil fuel reserves before we had found a more versatile and energy-dense alternative. . . . That system has been on the life-support of quantitative easing and near zero interest rates ever since. Indeed, so perilous a state has the system been in since 2008, it was essential that the people who claim to be our leaders avoid doing anything so foolish as to lockdown the economy or launch an undeclared economic war on one of the world’s biggest commodity exporters . . . And this is why the crisis we are beginning to experience will make the 1970s look like a golden age of peace and tranquility. . . . The sad reality though, is that our leaders – at least within the western empire – have bought into a vision of the future which cannot work without some new and yet-to-be-discovered high-density energy source (which rules out all of the so-called green technologies whose main purpose is to concentrate relatively weak and diffuse energy sources). . . . Even as we struggle to reimagine the 1970s in an attempt to understand the current situation, the only people on Earth today who can even begin to imagine the economic and social horrors that await western populations are the survivors of the 1980s famine in Ethiopia, the hyperinflation in 1990s Zimbabwe, or, ironically, the Russians who survived the collapse of the Soviet Union."

https://consciousnessofsheep.co.uk/2022/07/01/bigger-than-yo...

What in the world does any of that have to do with birth rates and overpopulation, which is the only thing I mentioned? Are you just spamming a link and quote?

Or will it be that people just don't find life worth living and stop having children? E.g. South Korea.

Nearly all developed countries have birth rates below the replacement level. The cluster of reasons for this effect is indeed almost certainly why population levels will level off

And basically none of those reasons are related to the two proposed (“getting our s%%% together” or actual die-offs, both kind of cartoonishly silly). It’s largely the availability of birth control, urbanization, and maybe also old-age safety nets.

The whole world is on the way to doing this (Africa will, too, as they will develop… and, in a note of good news, probably become as economically powerful in the 22nd century as Asia is in the 21st). It’ll lead to a cratering of the working population unless we basically start to eliminate retirement (not desirable!) and enact a ton of pro-natalist policies now (in addition to as much immigration as possible).

A thing people don’t understand is that the biggest resource limit is people. Population decline won’t mean abundance but the exact opposite as the dependency ratio shoots through the roof and will be incredibly stubborn to come down (as to try to reverse it with pro-natalist policies will actually make it significantly worse for a couple decades), especially as willing migrants dry up (yes, I realize how counter-narrative that is, but it’ll happen… in the latter part of this century, Africa will become sick of being the cheap labor source of aging Europe and Asia).

Even with a pessimistic estimate about the rate of progress, fully general AI will be here loooong before population decline decimates the economy, as will good robotics and all the stuff needed to basically put resource gathering and production on autopilot. At that point "on welfare" would easily be the equivalent of living like a millionaire today.

The bigger questions are whether global warming or WW3 will fuck us all before we get there, not to mention the question of whether fully general AI will be its own mega disaster.

Population decline will be a problem in your lifetime. I’ve become disillusioned with the idea that hyper-automation is just around the corner. Observing a Chrysler assembly plant from almost a century ago, vs our current car assembly plants (wiring harnesses still very stubbornly manual), has tempered my expectations of automation progress, as has the slowing of Moore’s Law and the failure of self-driving-cars to materialize in the last few years.

Seeing modern day "best in class" is a great way to become pessimistic about progress, you see the best of now but don't realize it's the worst of "soon". In 8 years you'll reverse course completely based on machining automation, and in 11 we'll have true AGI.

For what it's worth, for me 'getting our shit together' is shorthand for availability of birth control and improving availability of mass education, especially for women. These are the things that have concretely driven reduction in population growth.

I agree about that, but the implication was that we are doing those things to slow or reduce population, not just, you know, because we ought to do them anyway.

Yes, but South Korea is leading the pack. Something unusual since they only industrialized in the 1970s and were poorer than North Korea until the 1980s.

E.G. China.

tang ping

You don't even have the beginnings of any meaningful predictive curve with just a few data points. It's just selective function fitting if there's not a rich data set. For example, you can draw many curves through 2 data points, but you can also draw a straight line. The Our World in Data "Primary vs. planted forest" data that he cites for the "Old Growth Forest Cover" chart has just 2 data points (1990 and 2019).

> You don't even have the beginnings of any meaningful predictive curve with just a few data points. It's just selective function fitting if there's not a rich data set.

Having a rich data set doesn't help. https://twitter.com/SonerCagaptay/status/1389387850551005192

Don't forget the infinite families of higher order polynomials that can have arbitrary shapes beyond the point the observed data ends.

How many physical systems are of those higher order polynomials? Don't most systems have a low number of forcing functions?

> A hockey stick is the initial part of an S-curve.

It's also the initial part to a bell curve.

The downward slope after the peak of this bell curve happens when the population dies off.

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