If you ever want to feel really old, go to Population.io [1], enter your date of birth and country (fake it a bit if you wish), and look at how many people in the world are currently younger than you. This is both fascinating and shocking even if you enter the information for any smaller children you know (from the last decade or so).
Wow, pretty interesting. I compared to the US and it turned out that I'm expected to live 0.2 year longer than if I was from the US. I'm from a third-world (Tunisia if you are curious), so that was totally unexpected. The Life expectancy here is pretty high comparing to other developing countries.
[My limited knowledge and reading of this is reflected here]
There are genetic, dietary and lifestyle factors. Genetically and historically, people were used to famines and lower availability of food. So the body evolved to store up whenever food consumption increases. This applies to large parts of the population in Africa too.
With affluence and affordability improved drastically in the last few decades, people tend to eat more and richer food, which forces the body to store as fat. This triggers Type 2 diabetes, hypertension and heart disease. Diet wise, the consumption of dairy is quite high (not as high as some developed countries though) - significantly higher than consumption in the past. This combined with genetics makes things worse, and a lot of lacto-vegetarians also tend to suffer from the lifestyle diseases mentioned above.
One thing that is a little bit off in the analysis is the statement
"China, India and Africa are (and have been for a long time) the most populous regions in the world"
Actually, according to that data, Africa only overtook Europe in population between 1980 and 1990. I remember when that happened, because I'd always assumed Africa had far more people. They will, but it hasn't been for 'a long time'. It was quite recent really.
Historically Africa had very little population growth compared to the tiny population that survived the "out-of-africa" exit.
I would speculate: part of the reasoning for this would be the lack of domesticable livestock, and why that would occur in the place where humans had evolved from simple inefficient sapiens.
It's actually much more simple. It's just urbanization vs rural. As urbanization increases, population density can increase. Until very recently Africa was mostly rural.
With the Sahara and Kalahari, Africa will be desperately overpopulated long before it matches Europe or China for total density. There's simply a vast and growing uninhabitable fraction of land in Africa.
Increasing population pressure is actually already causing desertification that make it worse.
Peak population will be a huge paradigm shift for the world economy. For the entire history of the world we have relied on growth, and the main deiver of economic growth has been population growth. No more!
Peak population isn't coming in the next few centuries. The 2008 UN data these charts are based on had mistaken data on African growth. African fertility is much higher than expected then and continues not to fall.
The later 2100s in these charts now look to add several more billion and growing, almost all in Africa. Or from Africa; migration from poorer and overcrowded countries means Europe will probably be majority African by 2100 and have several hundred million more than shown in these charts also.
The post-2008 revisions of UN projections are quite sobering about the future and sustainability of humanity. We are not on a path to sustainability. We are cratering full speed toward a potential Great Filter.
If somebody does not have imagination about what will happen then I would recommend to study the art of wine making. It has some quite valuable lessons to teach.
Sourdough breadmaking and all the culture you have to constantly throw away to keep it from metastasizing or getting infected is very informative also.
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.)
It would be a "modest increase" if we had spare carrying capacity. Instead, what we have now is a situation that is going from bad to worse, but since the crisis is unfolding in slow motion, most people do not recognize it as such; after all, most people alive today have either never seen what a good situation looks like, or where too young to grasp the meaning of the changes they observed back then.
The (human) carrying capacity of Earth was estimated to be around 2 billion, which was surpased sometime in the late 1920's. Contrary to other comments here, that does not mean that after you hit population 2,000,000,0001 we all die (we clearly did not). Instead, what it means is that given the technological level we had at that time, we'd consume renewable resourses faster than they can renew themselves, and we'd also produce waste faster than the environment can degrade it. Otherwise, more than 2B people would cause environmental degradation, which would itself reduce the carrying capacity in the long term.
Please note this definition is tied with humans technological level. It is not set in stone, since we have some degree of control over our impact in the environment, and we have the ability to use the same resources in a more efficient way. The big tragedy of 20th century is that this fact was not recognized but for a handful of theorists, and therefore it was not a political and economic goal to explicitly manage the carrying capacity of Earth. As of 2016, the situation is still the same.
By example, we gained a bunch of technologies that allows us to do the same stuff more efficiently. Given explicit economic incentives, we might have... maybe doubled our carrying capacity (CC=4B). Unfortunatelly, because this was not a goal itself, we engaged in a buch of economic practices that negated much of this benefits, so if we are generous these might have been reduced by half (e.g. CC=3B). Also given that population growth was not arrested back in the 1970's, but only slowed down, the carrying capacity has not improved at all (CC=2B).
Currently, environmental degradation is going in overdrive. We have lost a lot of time, and the resources we need to make an orderly transition are already commited to keep the system going. Population will go down, one way or the other. I don't believe in a single sharp die off many apocalyptic thinkers profetize, but adding and extra 1.6B mouths to feed will make the downward tendency of the curve more steeper than it needs to be.
By whom? A source would be nice, which is why I generally refrain from using passive tense when stating facts.
> Also given that population growth was not arrested back in the 1970's, but only slowed down, the carrying capacity has not improved at all
How exactly does population growth affect carrying capacity? If I have a car with 7 seats, its passenger capacity is the same whether I have no passengers or 6 passengers. If population is an intrinsic factor in carrying capacity, then whatever definition of carrying capacity you are using is inadequate.
Medieval economy relied heavily on wood consumption, in a very unsustainable way. Forests were cut down way faster than they could renew and, if no technological change happened, they would have hit a wall pretty violently.
But they didn't. Instead, people and societies adapted.
The lesson of that is that you cannot extrapolate our current technology and the resources we consume in the future and assume that everything will stay the same.
It's like saying medieval societies should have stopped growing so they could sustain on the wood they cut down.
>The lesson of that is that you cannot extrapolate our current technology and the resources we consume in the future and assume that everything will stay the same.
I am reminded of an old joke:
"A man jumped from the 10th story and is falling to the ground. A woman at the 4th floor sees him from her window and asks, 'Hey, how's it going?'. The man replies 'So far, so good.'"
Yes, technology has saved us in the past. Given that new discoveries are increasingly harder and more expensive to achieve, will technology continue to do so in the future...?
The number of clever high-IQ people and engineers will continue falling. It's only the nations and cultures that don't value learning and invention that are expanding.
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.
Don't forget Carl Bosch! Everyone forgets Bosch for some reason. You can't just have chemist discover a process, you need a chemical engineer to make it work on an industrial scale.
Sure, just like if Einstein hadn't discovered relativity someone else possibly/probably would have. And maybe in another part of the multiverse someone else did. It's still interesting to trace back the chain of events that lead us to where we are today, and examine the agents of some of the most impactful events, however incidental they may be
This paper http://na.unep.net/geas/archive/pdfs/geas_jun_12_carrying_ca... by a UN group surveyed studies of the "carrying capacity" of the Earth. The bad news is that the largest number of studies say we are near the bounds of capacity. Worse, many studies say we have overshot sustainable capacity.
But there many studies that claim carrying capacity is much higher than current population, and that the projected 16 billion simultaneous living humans is within capacity.
It seems like whether we have a soft landing at the end of the oil age could dominate any calculation. The ability of renewables to scale up is only just crept past the starting line of a long, but necessarily urgent race. I'm not very enthusiastic about the odds.
As population is one of the indicative of productivity (although a weak one), you can see how many big events were driven by population growth. For example,
- During World War II, US had more people then Germany, France and UK combined. This certainly enabled deployment of massive armies on many front and huge amount of weapon production.
- Japan's population suddenly started rising and overtook many western countries. Its increased productivity might be the reason why this tiny country felt it can take on the world.
- India and China are odd balls. India had massive population since very early times compared to European countries.
-Somewhere in 1870, US population crossed a threshold and became the most populated western country.
-Population for 2100 AD is estimated at 10 billion.
If there are heritable traits that lead to people having more kids in a developed world environment then at some point evolution will take over and we'll start to see exponential growth again.
This assumes that biological evolution is the only systematic effect on population growth rate. I would argue that the fact that we have decreased infant mortality at the same time as decreased population growth is evidence that there are other systematic pressures limiting population growth.
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 prevalence of those alleles to increase and the birth rate to rise again. When I look around at my social groups most of the people I know enjoy sex but there's a lot of diversity in how much people are interested in having kids. I don't have any basis for saying if that's a heritable trait or not. But if it is heritable then I'd expect people like that to be the majority before all that long and in the long term population growth to become exponential again.
And in the very long speed of light limitations mean that the resources available to humanity can grow cubicly at best so if exponential growth resumes Malthus will be with us again at some point.
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 running for all of human history, and it's not like we're having 400 kids per woman these days. Besides, r-strategists don't always beat out k-strategists.
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:
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.
> 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, roughly, but the assumptions don't hold for humans because of the changes in behavior.
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 conditions will return; Darwinism requires it.
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.
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.
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 large family for security in old age, etc.
Estimates of the "replacement fertility rate" are about 2.1 per woman in a developed society (higher in less-developed societies). Many first world countries are already below this rate, and without immigration, will have declining populations as their native populations age.
Malthus and his disciples have been wrong for 200 years.
Paul Ehrlich in particular, because he used to like giving short-term dates for his predictions, so we could watch them slide by. Then he decided time was different to him than to an "average person".
“How many years do you have to not have the world end” to reach a conclusion that “maybe it didn’t end because that reason was wrong?” -- Steward Brand, former disciple of Ehrlich
Well, Paul Ehrlich is an entomologist, so it's not too surprising that he should consider human populations to be essentially automatic, mindless swarms.
The population was rising before the first antibiotic was discovered so I'm guessing that it won't make all that much of a difference. In general public sanitation made a much larger difference in the reduction in death by infectious disease since the 19th century than medicine has.
And ironically Public Health is the lowest, least respected medical specialization. Doctors practicing that earn like plumbers or construction workers. Yet we all own them our collective health and well-being.
Just a note, in the first figure, the annual population growth rate is shown as the percentage of the population size at that time, not as absolute growth rate in number or humans added. Neither is more correct than other, but they are different ways to present things.
Not sure, I think that linear scale is more understood.
My only complaint is that the graph 5 should have been ordered by the population growth rate because as it is now leave a bit distorted general picture.
Also if the timeline could be adjusted. Lots of things are more interesting if the first 4500 years of no data could be skipped so we could actually see the recent developments.
I would rather say that the population growth that is only taking place outside of western democracies (with some minor exemptions), is the main reason behind the loss in living quality, as the explosion of the world wide population living below acceptable western standards puts the pressure on the wages all over the globe.
Being it through imported goods made in a country with much lower wage standards, or through stagnating wages of low skilled jobs due to immigration (please note that I just state that somebody new in some society is most of the time in more difficult position and is more willing to accept an offer considered not acceptable for longer time residents).
I understand that many societies value highly a human life but as irony had made the human life less valuable around the globe though this worldview.
The other countries with well educated young people that could contribute also have falling populations. The nations of Africa (and similar Guatemala, Bolivia, Gaza, Afghanistan) with high illiteracy, high violence, and near zero higher education are the ones that have extra emigrants to offer.
That kind of immigration is the only kind available and it isn't going to help anyone support higher standards of living in the short term.
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 new kids are born, the 15 existing kids become adults, 30 adults retire, and the 5 existing retirees die. Bonus: we got 3% better at making widgets, so a working adult makes 51.5 widgets. We now have 100 people, 5 kids, 30 retirees, and 65 working adults. Total widget production = 65 * 51.5 = 3,347.5 widgets per year, or a per capita income of ~33.5 widgets. Again, policies can change the distribution, but not the total number.
What we're seeing is that if an aging workforce lowers the overall workforce participation rate, as a society, we get poorer. If productivity increases, as a society we get richer. It's just a question of which change is larger, and in the US (and Europe, and much of Asia) the answer is the aging workforce. The demographics are clear and brutal.
The most critical metric is the ratio of current workers to retirees; that number is climbing and is going to continue without a policy change that somehow reduces the number of retirees, or increases the numbers of workers. Large scale skilled immigration might do the latter, but failing that, we're basically out of ideas.
What you're describing is a pyramid scheme. Get more and more new people in to pay for those already there. If immigration falls or stop rising you suddenly have a problem.
A more robust, sustainable solution is to improve productivity via other means (including automation).
Keep in mind that immigration is actually a small part of this; the much much more important element is birth rates. The core issue in the US is that we made promises based on an economy where the baby boom generation was working to support their parents in retirement, but we're going to need to pay up in an economy where millennials are working to support the baby boom generation in retirement.
> A more robust, sustainable solution is to improve productivity via other means (including automation).
Sure, that would be nice. It's also completely impossible. Productivity growth has never, ever, ever grown fast enough to bail us out of the hole we're in now, and we have zero (repeat, zero) ideas on how we could possibly change that.
> What you're describing is a pyramid scheme. Get more and more new people in to pay for those already there
That's how retirement works in most countries. The tax burden mostly falls on the "productive age" (18-65), so until automation pays as much taxes as the humans it replaces (corporate tax dodging considered), retirees in countries with shrinking populations are screwed.
150 years ago, 90% of Americans worked in agriculture. Today 2% do and we are better fed. Population growth or shrinkage cannot match productivity technology as the key factor in material quality of life.
Countries with falling populations will just need more robots. Mass immigration isn't going to help, but this is one of those problems easily solved with tech.
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'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.
A society just needs to maintain its population, perhaps with little growth to edge the losses from unaccountable forces.
Growth is not needed, only thing that should be checked is that the growth does not become negative. This should not be patched by the immigration, as it will just delay the problem, not fix it.
> Again, policies can change the distribution, but not the total number
Indeed, policies can change the distribution. If one of the 100 people is getting 800 of the 4000 widgets produced, you can probably make some policy adjustments before coming to the conclusion that you're not producing enough stuff.
While I see the point you're trying to make, your math assumes widgets last exactly 1 year, which is generally not the case with most goods, except those produced for immediate consumption and maintenance e.g. food, gasoline, hygiene and health products.
Also, the basic math can be so vastly different in reality, that there will be huge leeway in terms of how many people can retire.
> The most critical metric is the ratio of current workers to retirees
America has been quite successful with immigrants getting jobs. But in Europe some countries have for a while got a kind of immigration situation where unemployment among the migrants stays so high that they are actually worsening the ratio of workers to total population.
3% is a pretty low number for productivity gains during a span of time when 60% of the existing workforce retires. As little as 24% increase in productivity, or 8 years of 3% annual increases, is enough to have a gain in your example.
1. Corruption in Zimbabwe. Commercial farmers have been abandoning productive land and the country is getting poorer.
2. Communism in Cuba, Venezuela, SE Asia, and other regions over the past fifty years has ruined developing economies and made them worse. Most of those governments have fallen and things are improving again, but communism certainly has the power to ruin a country.
I'm sure there are others. Technological progress has give us a strong underlying upward trend around the world lately but sufficiently bad government can occasionally reverse the benefits of progress temporarily.
Thanks, these are good examples. It's amazing how long some of these corrupt governments have stayed in power. Will be interesting to see what happens if/when there's a change in governance.
It's easy to stay in power when you have complete control over the news and propaganda machines. Using Venezuela as an example, the country is one of the richest in the world in natural resources, but 1% of the population controls 99% of the wealth.
Because Japanese debt is owned by Japanese households, yes. But if it decreases their standard of living, it's not a contradiction, it supports the point. They will pay the price of refusing immigration.
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.
[1]: http://population.io