World Population Growth • Hacker News Board

Re: World Population Growth

#101

Post by Lazare » Wed, Oct 12, 2016, 11:27 PM UTC

maxerickson wrote: post #16

Lazare wrote: post #11

Earlier quoted context omitted.

It's not so much a question of evidence as basic math. Imagine a society with 100 people. A working adult can create 50 widgets per year, and there's 15 kids and 5 retirees. The economy produce 80 * 50 = 4000 widgets per year, which gives a per capita income of 40 widgets. You can have whatever tax, welfare, or income redistribution policies you like, but there's only 4000 widgets to go around. Great. Now let's say 5…

That basic math illustrates things nicely but hides the real picture. There's about 2 million people working in agriculture and 1 million working in mining in the US: http://www.bls.gov/emp/ep_table_201.htm And about 5 million working in the energy industry: http://energy.gov/articles/doe-releases-first-annual-nationa... Our widgets are built by machines. This too is a facile picture of the situation, but our materia…

What you're talking about is the economic concept of "labor productivity". If we can use factories and automation to create the same amount of stuff with fewer people, then our productivity will rise. If it rises fast enough, then we could have more stuff per person even with fewer people working. Problem solved!

Except: Productivity growth has historically never been high enough to bail us out of the hole we're in, and it has been trending down in recent years for reasons we don't fully understand.

> our material abundance isn't particularly under threat from contraction of the work force.

I wish!

Re: World Population Growth

#102

Post by wolfgke » Thu, Oct 13, 2016, 12:27 AM UTC

b_emery wrote: post #98

WildUtah wrote: post #84

Earlier quoted context omitted.

There are people, even in Japan, that want a whole mess of children. That preference is heritable. Each generation has more of these people because they're the ones that reproduce. Eventually those fertile and natal enthusiasts will dominate the population and exponential growth resumes. The current situation is a temporary response to an external shock, specifically to reliable contraception. But Malthusian conditio…

I respectfully disagree. Your assumption about the preference being heritable is questionable.

Couldn't it not be a gene but a meme that is inherited, instead?

> Each generation has more of these people because they're the ones that reproduce.

I.e. each generation has more of these people since people who see having children as something positive reproduce and teach these values to their children.

Being a memetic instead of genetic factor would have the advantage that it is easier to "unprogram" it, i.e. by having rules/incentives in the society that discourage reproduction or by education.

Re: World Population Growth

#103

Post by wolfgke » Thu, Oct 13, 2016, 12:30 AM UTC

eveningcoffee wrote: post #35

collyw wrote: post #20

Earlier quoted context omitted.

My simplistic version is that our economy is basically a ponzi scheme that needs new entrants to fuel the "growth".

Actually not the children, as they are the expense It needs the people in the productive age. Immigration of young adults is economically the best solution in short term as it leaves the expense of growing them up to the other societies.

> It needs the people in the productive age. Immigration of young adults is economically the best solution in short term as it leaves the expense of growing them up to the other societies.

And introduces pension problems for pension systems that are based on an inter-generational contract.

Re: World Population Growth

#104

Post by maxerickson » Thu, Oct 13, 2016, 12:39 AM UTC

Lazare wrote: post #101

maxerickson wrote: post #16

Earlier quoted context omitted.

That basic math illustrates things nicely but hides the real picture. There's about 2 million people working in agriculture and 1 million working in mining in the US: http://www.bls.gov/emp/ep_table_201.htm And about 5 million working in the energy industry: http://energy.gov/articles/doe-releases-first-annual-nationa... Our widgets are built by machines. This too is a facile picture of the situation, but our materia…

What you're talking about is the economic concept of "labor productivity". If we can use factories and automation to create the same amount of stuff with fewer people, then our productivity will rise. If it rises fast enough, then we could have more stuff per person even with fewer people working. Problem solved! Except: Productivity growth has historically never been high enough to bail us out of the hole we're in,…

I'm not talking about productivity growth at all, I'm pointing out that economic productivity is not evenly distributed throughout the economy. Losing 10% of farm acreage would be a disaster for quality of life. Losing 10% of fastfood stores would barely matter.

Re: World Population Growth

#105

Post by sumedh » Thu, Oct 13, 2016, 12:46 AM UTC

triplesec wrote: post #59

MollyR wrote: post #52

Earlier quoted context omitted.

This is an anecdote. I have coworker friend who is from india, and he told me most of the men in his family die from heart attacks from age 40-50. I thought it was weird as heck, but when I researched it showed they had 4x for heart issues against the general population in america. https://stanfordhealthcare.org/stanford-health-now/2015/sout...

Any idea of why this might be?

Poor diet, we eat lot of fried food. We eat lot of Indian sweets (to be fair they are really good) and we dont exercise.

Re: World Population Growth

#106

Post by kbutler » Thu, Oct 13, 2016, 1:11 AM UTC

WildUtah wrote: post #84

b_emery wrote: post #83

Earlier quoted context omitted.

> The only way to long run sustainability is central control of population with mandatory birth limits This is demonstrably not true. Look at Japan and western Europe: declining population. Its a function of economic situation (no need for more than 1-3 children) and female reproductive choice. If we give that to the world, the population problem goes away. The mathematics of population dynamics work for animals, rou…

There are people, even in Japan, that want a whole mess of children. That preference is heritable. Each generation has more of these people because they're the ones that reproduce. Eventually those fertile and natal enthusiasts will dominate the population and exponential growth resumes. The current situation is a temporary response to an external shock, specifically to reliable contraception. But Malthusian conditio…

Statistics suggest your view of Darwinism is incorrect.

http://www.infoplease.com/ipa/A0884238.html shows avg household size has been declining since before contraception, and it doesn't look like contraception changed the slope.

Re: World Population Growth

#107

Post by IkmoIkmo » Thu, Oct 13, 2016, 5:45 AM UTC

davidiach wrote: post #56

weatherlight wrote: post #41

Earlier quoted context omitted.

I really don't think earth is going to be able to support 9 billion people without some sort of dramatic paradigm shift in the way, as a species, we consume things

9 billion is 1.6 billion more people than we have today. What dramatic paradigm shift do we need for the earth to be able to support such a modest increase?

You have to consider though how many of our current 7 billion people:

- don't use toilet paper - don't drink milk - don't travel more than a few miles from their birthplace

etc etc, and that will be shifting quite quickly, I believe. It took centuries for industrialisation to get e.g. Europe past such reference points of wealth, after two hundred thousand years of most of humanity living roughly without significant improvements in wealth. But it only took a few decades for e.g. China to lift hundreds of millions out of poverty and towards some form of middle-class.

You can debate some of the details for sure, my overal point is that we're not just going to add a few billion people to this planet, more importantly, we're going to add a few billion middle-class people to this planet. It's not the billions who live off of subsistence farming, who's impact on the environment is not all that much more substantial than any other animal grazing in a field, that is the big environmental issue. It's the fact that those people become more like us, drive cars, run refrigerators, eat energy-inefficient meats, have a shower in the morning and evening, live in large homes that must be cooled and warmed, eat more than necessary etc.

If you look at some figures that state we consume 10x more energy (making up a number here) than a subsistence farmer... it's more the economic shift from poor to rich we may need to worry about from an environmental, than raw additions to our global population.

(disclaimer: not implying I have anything against poor people getting richer, purely looking at it from an environmental perspective. Also, there's opportunities in a richer planet to build environmentally sustainable infrastructure, too, but on aggregate it'll bring some big issues to the table, far bigger than adding 1.6 billion poor people to our population, I think.)

Re: World Population Growth

#108

Post by Symmetry » Thu, Oct 13, 2016, 12:39 PM UTC

hx87 wrote: post #77

Symmetry wrote: post #68

Earlier quoted context omitted.

There are certainly things about that modern world that are pushing population growth rates lower. The availability of birth control and more legal rights for women prominently among them. That's why the population growth rate should be leveling out in 80 years or so. But looking forward maybe 800 years, if there are alleles which tend to make people more likely to want and have kids then I would expect the prevalenc…

That 800 year extrapolation assumes that humans won't have access to genomic modification though, which is unlikely. In any case, the number of kids one has is highly culturally and environmentally dependent--the same people whose great grandparents had 4-6 children now routinely have 1-2. Even in a purely natural-selection sense, if "having more kids" were significantly heritable, the process should have been runnin…

That's possible but I'm not sure why someone who would prefer more descendants would genetically modify their progeny to not prefer more descendants. If this is a government imposed eugenics plan it could certainly work, though.

For most of human history a desire for sex was quite sufficient to ensure reproduction even without as much desire for children. With the advent of birth control the environment changed and there are new selective pressures. Also the modern world has a lot of new, competing, sources of joy.

R strategies certainly don't always beat K strategies! But humans are currently in a very rare situation where our population seems to be very far below K and most people in wealthy countries aren't living anywhere near subsistence level. So, until Malthus rears his head again, evolution is going to be paying a lot more attention to r.

For those following along at home, for N as the number of individuals:

  dN/dt = rN(1 - N/K)

Re: World Population Growth

#109

Post by dharma1 » Thu, Oct 13, 2016, 1:31 PM UTC

pmoriarty wrote: post #62

dharma1 wrote: post #50

In a large part thanks to this guy, who invented a process for extracting nitrogen from the atmosphere - an invention that now feeds half the Earth's human population. https://en.wikipedia.org/wiki/Fritz_Haber https://en.wikipedia.org/wiki/Haber_process Cheers, Fritz

Radiolab had a great episode on Haber: http://www.radiolab.org/story/180132-how-do-you-solve-proble...

that was a great listen, thanks

Re: World Population Growth

#110

Post by snrplfth » Thu, Oct 13, 2016, 4:10 PM UTC

kbutler wrote: post #90

WildUtah wrote: post #34

Earlier quoted context omitted.

Yes. The only way to long run sustainability is central control of population with mandatory birth limits or unlimited expansion of land area to extraterrestrial territory. Otherwise evolution will always exceed its limits and produce a crash. Malthus explained it all mathematically 200 years ago, even before Darwin documented the mechanisms.

Did you forget the /s tag? It's pretty well understood that population growth curves are logistical, rather than exponential (e.g., https://www.britannica.com/science/population-growth/images-... ) The appearance of exponential growth is always temporary. As the population increases, negative feedbacks reduce the population growth rate. Examples of these feedbacks include cost to raise children, reduced dependence on…

Well, Paul Ehrlich is an entomologist, so it's not too surprising that he should consider human populations to be essentially automatic, mindless swarms.