Think Again: Global Aging
foreignpolicy.com
foreignpolicy.com
Trivial example: If an initial fraction f (with 0 < f < 1) of the population has a large growth rate of 5%/year and the rest of the population has a small negative growth rate of -1%/year, then the population as a function of time t in years is N[f(1.05)^t + (1-f)(0.99)^t]. For f = 1%, it takes less than a century for the growers to dominate the shrinkers: http://i.imgur.com/kv3KZ.png (blue is with f = 1%, red is f = 0%).
A few people are partially or fully immune. (You don't have to be Mormon to be well off, educated and absolutely need to have 4+ kids) and over time their numbers will come to dominate.
I hope we've colonized space by then.
http://www.blume-religionswissenschaft.de/pdf/ReproductiveRe...
(PDF; p. 119, fig. 8.1)
Note that people who attend church/temple every week are well above replacement rate. The evolutionary race is on: those religious groups who manage best to transmit their "grow and multiply" gospel to their children will dominate demographics, and consequently politics, within our lifetimes.
I've never understood this.
A preference for large families seems logically unlinked to the primary evolutionary benefit of religious beliefs as I understand them: the cooperation level that is feasible when there is a powerful, omnipotent god to punish norm-violators.
Yes, religions which incorporate ideals about large families will tend to spread, but the same can be said about non-religious cultural memes.
And, in fact, shouldn't secular humanism (which stress the worth of people independent of their service to a god) be more compatible with large-family ideals than traditional religions (which stress duty to god over duty to self and others)?
EDIT: I read quickly though the paper you linked. It doesn't seem to answer my question. Rather it assumes the link between religion (belief in a judging god) and large-family ideals, and then arrives at the natural conclusion that religions are evolutionary advantages.
Or did I read it wrong?
The only such meme that ever had success comparable to religion was nationalism, but it self-destructed in the world wars.
Rationally speaking, I think it's well established that having kids is a huge chore. Morning sickness, birth pains, changing diapers, lack of sleep etc. etc. etc. If you had any doubt, the first baby will quickly cure you of it.
The only way for people to put up with all this, and raise large families, is to strongly believe, as you say, that they have an important _duty_ to do so. Giving birth for the benefit of the nation is no longer fashionable, but the various gods' appetite for fresh believers has never diminished.
By contrast, there is absolutely nothing in the world view of the "Sex and the City"-watching woman that will ever lead her to raise five kids.
Sure, but why aren't their such memes? I can imagine all sorts of hypothetical cultures which don't feature judging gods but do feature a duty to have children.
(By the way, how do you do italics on HN?)
There might be a short-term blip of excess births as we all get used to the new equilibrium. That is sort of how we ended up with an excess of old people today. But since the magic that doubled our life expectancy probably didn't also double our food, oil, and fresh water supplies, we'd soon see birthrates drop to maintain equilibrium.
But why settle for doubling? Why not make humans immortals? Oops! Now you have abolished children! Sell that Toys R' Us stock.
Or is the idea that our Philosopher's Stone will enable us all to live the healthy lives of twenty-year-olds up to age 150, at which point everything collapses at once and we die in one instant, like the wonderful one-hoss shay? Um, good luck with that.
In summary: changing the nature of life expectancy will change the nature of our demographic weirdness, but is unlikely to produce anything less complicated.
In that case - even if people still live roughly 65-90 years, the age distribution of the population stops being such a matter of importance. If, at 80 you still feel and heal like a 50 year old there's much less problem with a) who is going to work and b) who is going to look after you, since you can work and you don't need anyone to look after you.
And isn't that the main concern of this kind of examination of age distribution?
That is sort of how we ended up with an excess of old people today.
Excuse me? "excess"?
But since the magic that doubled our life expectancy probably didn't also double our food, oil, and fresh water supplies, we'd soon see birthrates drop to maintain equilibrium.
Yes, and that would be fine.
Why not make humans immortals? Oops! Now you have abolished children!
What do you mean "oops"? Also, people would still die from other causes.
In summary: changing the nature of life expectancy and changing the nature of aging are different things. Anti-aging research isn't supposed to be focused on the "surviving 90 times round the sun" bit, but on the "chronic disease, weakness, and disability" that comes with it.
Sounds good.
Oops! Now you have abolished children!
Several possible solutions come to mind. A ridiculous solution, which would still be a tremendous improvement over the status quo, would be to institute a Logan's Run policy where you get 100 years of good health and are then painlessly euthanized. But really, I think concerns like that are analogous to the doomsayers 120 years ago who predicted that given current trends New York would be waist-deep in horse manure by 1950. More likely, I would expect a temporary drop in the birth rate, while we get serious about colonizing space (which we should do regardless, on the egg/basket principle).
In summary: changing the nature of life expectancy will change the nature of our demographic weirdness, but is unlikely to produce anything less complicated.
Things would be different, yes. And given that right now aging is responsible for an impending fiscal train wreck, as well as incalculable suffering and destruction of human potential, we badly need something different.
For example, if we have 1 billion people who suddenly all become immortal, and each couple has, on average 1.8 children, we asymptote towards a world with 10 billion immortals. Everyone could have offspring, though the actual number of young people would be continuously decreasing...
If $p0$ is the starting population, and $a$ is the number of children per person (number per couple divided by two), we have
p = p0 * sum_{i=0...inf} a^i = p0 / (1-a)Cronkite still reading the news. The same NYT and WSJ editorial staffs for many decades.
The same scientists and writers getting all the speaking engagements, more or less forever.
At least right now these people eventually get old and go away. We'd be stuck in a horrible stasis without that.
I'd like to suggest a fourth course of action: do nothing. We are not an endangered species. If we need more people, we'll make them. There is nothing in the universe that people like more than making more people. If they're declining to do so, they probably have good reasons.
We have 10% unemployment in the USA, our jobs growth rate is so anemic that we're projected to take decades, plural decades, to recover to full employment, and productivity keeps going up. Thanks, but I'll wait until -- at the very least -- all my unemployed friends are fully employed in caring for the elderly before I start worrying about a shortage of humans.
Considering the number of jobs that have moved overseas, and the malinvestment that has occurred in the last 10 years, I'm amazed that the unemployment rate is only 10%. (Actually, it isn't....so many people have fallen out of the categories considered unemployed, it is an artificially low number...the real number is likely somewhere between 15% and 20%).
And if all the young people are in jobs caring for the elderly (for which no one has the money to pay for), who will grow food, build houses, manufacture goods?
China? Well, it's worked so far I suppose.
http://www.sciencemag.org/cgi/content/summary/329/5997/1287
(Ungated summary: http://www.iiasa.ac.at/Admin/INF/PR/2010/2010-09-09.html )
The issues are political, not demographic. In many western countries, old people (in their youth) voted in governments which promised to force their children to pay for them to comfortably retire.
A very presumptuous statement, and not backed up by that study. While it is true that there is a large increase in life expectancy, there is a much larger increase in life expectancy beyond the point where the person can no longer work. Much of this could be solved in the future with greater attention to exercise later in life, proactive re-training for a career shift to accommodate reduced mobility, etc, this is not yet being done in a meaningful way.
> The issues are political, not demographic.
Bang on here. If you look at the actual math comparing what the boomers put into the system vs what they are taking out, and compare that to optimistic projections for the current working generation, it is pretty scary. This article touches on some of the issues: http://www.cbsnews.com/stories/2007/03/01/60minutes/main2528...
IMHO, a lot of programs and entitlements need massive, intelligent reform, and soon. And even then, I think a good deal of luck will be required as well.
One can come up with a variety of qualitative theories of how nothing bad will happen (you can't predict the future, new technologies, etc), but looking at it from a quantitative perspective, I just don't see an easy way out. I hope I'm wrong.
According to the paper, the ADDR (Adult Disability Dependency Ratio) will remain at about 0.1 in most countries listed for the forseeable future. In the US, the old age dependency ratio will increase from 0.21 to 0.38, but ADDR will increase only from 0.9 to 0.1. I.e., 2x as many old people, but the same number of people who can't support themselves (as a fraction of population).
That means that while there is an increase in old people, there is not an increase in disabled old people. It's not just life expectancy that is going up, it is also "disability free life expectancy".
The social security trust fund contains something like $2.4 trillion. Current projections are that if nothing changes then it will continue growing until 2025 and not be empty until 2042. See, e.g., http://en.wikipedia.org/wiki/Social_Security_Trust_Fund .
All that stuff you've been told about how Social Security was bankrupt, and "reform" was urgently needed, and so on? None of it was true. I shall refrain from speculating here about the motives of the politicians and pundits who said it.
Heck, they could have $25 TRILLION in the SS trust fund, and it would be the exact same thing, the number is meaningless.
All of the money for the "trust fund" comes out of regular taxes.
So let's say they have to dip into the trust fund for 100 million dollars, that means that the regular budget will have have to increase by either 100 million, or 100 million in services will need to be cut.
This is not sustainable and with the government hemorrhaging money left and right I don't see how that 2.4 trillion will ever be repaid. Unless the dollar loses most of its value through massive inflation, which would be very very bad.
That's a different claim, of course, and a totally unfalsifiable one. (Suppose the Social Security trust fund did in fact take the form of a big vault stuffed with dollar bills, or something of the kind. It would still be true that the government could spend them on other stuff if it wanted to. You could equally say that "there is no trust fund".)
> So let's say they have to dip into the trust fund for 100 million dollars, that means that either the regular budget will have to increase by 100 million, or 100 million in services will need to be cut.
The trust fund contains $2.4T (or whatever the exact figure is) in Treasury bonds. That money is already accounted for as money owed by the government. It's part of the national debt. The fact that there's a big national debt may well be a problem, but it's not a problem specific to Social Security. It's a problem with all the other things that the government has spent money on, effectively raising the money by selling (kinda) T-bills to the social security fund.
I agree with the skepticism about his panic. There has always been the optimists and the pessimists, nothing new there. Projections >30 years into the future are mostly doomed anyways.
Moreover what often amuses me is how these analyses tend to ignore the predictable part of technological progress and how that negatively affects the relevancy of their projections.
We went from the first flight to the moon landing in 66 years. Autonomous cars are performing their first test-runs in real traffic today. Asimo & friends are demonstrating quite impressive tricks today.
Call me naive but personally I don't have the slightest doubt that a large portion of all jobs will be taken by robots in 60 years from now. This will not just change the job market or certain industries, it will fundamentally change how our societies work. He doesn't seem to consider that at all.
So, he's worried about the global population being half of what it is today in 2150?
2150?
140 years from now?
I guess his musings about 2150 are about as relevant as those that a person in 1870 could have made about today...
I guess his musings about 2150 are about as relevant as
those that a person in 1870 could have made about today...
In the US over the past 20 years, quality of life as a function of age has become an important area of study. HALE (Health Adjusted Life Expectancy) may be a better predictor of future geriatric needs.
Bah. They won't last that long. We all know the world's going to end in 2012, by similar mental functions.