

Think Again: Global Aging - m0th87
http://www.foreignpolicy.com/articles/2010/10/11/think_again_global_aging?page=full

======
jessriedel
Eventually a few cultures which promote large families (e.g. Mormons) will
come to dominate and reverse this trend. Anyone have the data to estimate how
long this will take to happen?

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%).

~~~
zeteo
Indeed. What a lot of these population-rate-below-replacement analyses are
missing is that the dynamics vary significantly among population sub-groups.
And one variable that is consistently associated with large families is
strength of religiosity - e.g., see

[http://www.blume-
religionswissenschaft.de/pdf/ReproductiveRe...](http://www.blume-
religionswissenschaft.de/pdf/ReproductiveReligiosityBlume2009.pdf)

(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.

~~~
jessriedel
> one variable that is consistently associated with large families is strength
> of religiosity

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?

~~~
zeteo
"religions which incorporate ideals about large families will tend to spread,
but the same can be said about non-religious cultural memes."

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.

~~~
jessriedel
> The only such meme that ever had success comparable to religion was
> nationalism, but it self-destructed in the world wars.

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.

~~~
zeteo
I guess duty is a hard concept to sell. It's much tougher to persuade you that
you have the duty to do something, than it is to, say, teach you a catchy song
or a spectacular legend. It helps a lot to be able to say "the all-seeing god
has laid this duty upon you". If you did manage to invent and spread a meme
that had the same effect, but didn't conflict with science, then I see a lot
of history-making potential there!

(By the way, how do you do italics on HN?)

~~~
jessriedel
Italics are obtained by putting words in asterisks.

------
orangecat
It is blindingly obvious to me, and apparently to hardly anyone else, that
curing aging should be a top priority of governments and researchers for both
economic and humanitarian reasons. About time for another donation to SENS...

~~~
mechanical_fish
How is "curing aging" necessarily going to help? If, tomorrow, we magically
doubled everyone's life expectancy, the age distribution of the population
would remain exactly the same. The X axis (time) would just be twice as long.

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.

~~~
orangecat
_Why not make humans immortals?_

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.

~~~
lliiffee
Actually, even if no one dies, we can still all have children without creating
infinite population, as long as we have, on average, less than 2 per couple (1
per person).

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)

------
aristus
Think again again? The article leads off with an old, wrong prediction caused
by extrapolating then-current population trends indefinitely. The rest of the
article is based on extrapolations of the _current_ population trends
indefinitely...

------
bluesnowmonkey
His only ideas for reversing population loss are government intervention,
abandonment of women's rights, and making children a good investment.

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.

------
mechanical_fish
I kind of like Longman's data but have never understood his sense of panic.
It's as if he's stuck in some kind of time bubble in which the world doesn't
suffer from a massive economic depression and a sizable excess of industrial
capacity.

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.

~~~
moe
The world will change, news at 11.

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...

~~~
meric

      I guess his musings about 2150 are about as relevant as
      those that a person in 1870 could have made about today...
    

Or even, less relevant, as technology, economy and population all change
exponentially.

------
brudgers
Life expectancy is a somewhat crude tool for prediction.

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.

<http://www.pophealthmetrics.com/content/4/1/14>

------
Kenw00t
Reminds me of <http://www.demographicbomb.com/>

------
Groxx
> _As for Japan, one expert has calculated that the very last Japanese baby
> will be born in the year 2959, assuming the country's low fertility rate of
> 1.25 children per woman continues unchanged._

Bah. They won't last that long. We all know the world's going to end in 2012,
by similar mental functions.

