Thursday, January 10, 2013

The Looming Apocalypse of Slightly-Less-Gargantuan Population Growth

So, apparently there is some reason to believe that the Earth's population will reach merely astonishing levels rather than inevitably apocalyptic ones.

This, of course is a disaster.

It's amazing to me that any sign that the population explosion is abating to any degree is immediately met with panicky predictions of underpopulation to the point of extinction. If you insist on worrying about the extinction of humanity, it isn't underpopulation that ought to worry you...

In the Jeff Wise piece at Slate to which I link above, we find the following:
That might sound like an outrageous claim, but it comes down to simple math. According to a 2008 IIASA report, if the world stabilizes at a total fertility rate of 1.5—where Europe is today—then by 2200 the global population will fall to half of what it is today. By 2300, it’ll barely scratch 1 billion. (The authors of the report tell me that in the years since the initial publication, some details have changed—Europe’s population is falling faster than was previously anticipated, while Africa’s birthrate is declining more slowly—but the overall outlook is the same.) Extend the trend line, and within a few dozen generations you’re talking about a global population small enough to fit in a nursing home

So this is roughly like going to your friend who weighs 500 pounds, and who is putting on an extra pound every week, but who has recently begun putting on only half a pound per week, and encouraging him to fret that, at this rate, he will die of starvation in five years.

The population is too high. We need to bring it down. That means going through a period such that, were the population growth rates of that period sustained indefinitely, the population would become too small.

However, there is no intention of sustaining those rates indefinitely, and no very good reason to believe that they will be sustained.

Look, too much and too little are not the only two options. And worrying about a too-small population right now--or any time in the foreseeable future--is madness.

In amongst the other weirdness here, we find the following:
Most of our friends have just one or two kids, too, and like us they regard the prospect of having three or four kids the way most people look at ultramarathoning or transoceanic sailing—admirable pursuits, but only for the very committed.
That attitude could do for Homo sapiens what that giant asteroid did for the dinosaurs. If humanity is going to sustain itself, then the number of couples deciding to have three or four kids will consistently have to exceed the number opting to raise one or zero. The 2.0 that my wife and I have settled for is a decent effort, but we’re not quite pulling our weight. Are we being selfish? Or merely rational? Our decision is one that I’m sure future generations will judge us on. Assuming there are any.
I'm genuinely baffled by this. Is the author actually trying to say that his decision to have two children is morally praiseworthy? Because of the threat of underpopulation three hundred years hence? This really does seem like ridiculous stuff. American should save more...but if they start saving more, then, if the rate of increase is sustained, they would eventually save so much that the economy would collapse. So does that make my failure to save more praiseworthy? I'll leave that as an exercise for the reader...

Look. We have too many people currently. Don't panic. It's not a panic-worthy situation. It's probably best if you can keep your number of kids under three, but, hey, there are folks like JQ and myself who are having zero, and it's not exactly a moral crime to have more, though it's probably morally sub-optimal in many cases. (Of course, it's better for better parents to have more kids, and better for worse parents to have fewer...but you know how complicated all that is...)  But: we want to start building down sooner than later. Now, if we succeed in bringing down the population, then we will, ipso facto, attain, for at least awhile, negative population growth. No one is suggesting that we maintain negative population growth indefinitely. When your overweight friend slows his rate of weight gain, you do not try to panic him about starving to death. If I'm sedentary and start thinking about exercising, it is idiotic to say to me "If you exercise non-stop for days you will die." Nobody, you see, is talking about doing that, and it's freakishly dumb to even raise the issue.

So, some good news: if we can survive through peak population--and we probably can--trends seem to indicate that we'll start descending back toward a saner, more sustainable population.

Now: the very last thing we need to do at this point is, through shabby reasoning, try to convince everyone that the regression toward a saner population somehow constitutes the inevitable demise of the species.


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