A fun exercise for the next time you meet someone who raves about the Vital Importance of the world achieving zero population growth Immediately! As in Right Now, and Yesterday Would Have Been Better:

Take that person's city and find its population density. I'm going to use Austin, Texas. It's a nice place, right? I've never been there, but everyone says it's lovely.

I couldn't find a nice neat figure for Austin's population density, but I did find the 2004 population for Austin/San Marcos MSA (Metropolitan Statistical Area), otherwise known as the greater Austin area: 1,412,271. (See also here.)

And the "basic facts" page of the city of Austin reports a land area of 271.8 square miles, so there are approximately 5196 persons per square mile in the greater Austin area. If you think that sounds like a lot, bear in mind that the population density of Hong Kong is about 16,517 persons per square mile (using the figure of 6380 persons per square kilometer and converting to miles)--most of them packed onto Hong Kong Island, where the density shoots up over 45,000 persons per square mile.

Austin's 5196 persons per square mile may be a little crowded, but it's nothing compared to other parts of the world. In fact, it's pretty good: 5196 persons per square mile = 5196 persons per 640 acres, which means we'd each get 0.12 acres of land to call our own, or 5227 square feet each.

So can we conclude that we'd all be pretty comfy at Austin's current population density? Okay then. Now take the world's 6.5 billion people and divide by 5196: To house all 6.5 billion of them at that density, we'll need a land area about 1,250,962 miles square.

That's a lot of land? Not really:

Alaska's land area is 570,374 square miles, plus:
Texas, 261,914, plus
California, 155,973, plus
Montana, 145,556, plus
New Mexico, 121,365, equals 1,255,182 square miles.

We even have a little left over. Of course, Alaska isn't the most hospitable place on earth. Even I don't want my armed fortress built in Alaska. Let's try something more scenic. How 'bout we sub out Alaska's 570,374 square miles for parts of Europe?

France's land area is 545,630 square kilometers, or 210,669 square miles. Spain's is 173,569 square miles, Italy's is 113,521 square miles, and Germany's is 134,835, giving us a total land area across the Atlantic of 632,594 square miles almost, but not quite, full of Austins. There, we're done. The world is now composed solely of France, Spain, Italy, Germany, Texas, California, Montana, and New Mexico. That's going to be an interesting little United Nations.

At this point your zero population growth advocate will likely shout, "Oh, come on! I'm not claiming the problem is land area; I am claiming we can't possibly continue to feed so many people! And what about energy and resources?"

Well? What about them? You're telling me we can't cram France full of Austins and provide them all food, shelter, transportation, etc., when we've got the whole rest of the world to harness for it, minus a few lonely mountainous states that no one was really doing much with anyway? (Sorry, California. I'm not sorry, Texas.)

Do I need to remind you that this country pays its farmers not to produce food? And how much fuel are we going to need if the most we're ever doing is taking road trips around the American West and maybe flying over to France to perform gourmet cheese raids occasionally? Hell, we wouldn't even need to heat our homes in the winter if we subbed out Northern California and Montana for warmer climes. We could put everyone there in Northern Mexico instead. Here's the CIA factbook page for Mexico--you work out the square-kilometers-to-square-miles conversion this time*. I've done enough here, I think. Just eyeballing it, though, I'd say we've got plenty of room down there. Plenty.

People who advocate zero population growth aren't really thinking, and they don't really care that people are starving in parts of Africa or being washed away by floods in Indonesia. They don't advocate zero population growth out of a desire to fix these things, because if what they really wanted was to fix these things, they'd run the numbers like I just did and figure out that zero population growth isn't going to fix anything. What if the world's population increases? What if it doubles? Well, go on: Run the numbers with 13,000,000,000 instead 6,500,000,000. I'm betting we still don't fill the continental United States, even at the rather comfy density of 5196 persons per square mile.

We have plenty of stuff. Some of have more stuff than we know what to do with. The problem is that not everyone has access to all this stuff. Some people--lots and lots of people, actually--live in countries where bad farming techniques destroy arable land, or in countries where crappy coal is strip-mined by the government for no discernible reason, or in countries where flood control is virtually unheard of, or in countries where the government thinks price fixing is the solution to every problem. No one's starving for lack of food and no one's freezing for lack of heat and no one's drowning for lack of dry land. People are starving and freezing and drowning because people, especially people in power, so spectactularly fuck up on making sure the food is grown and the energy's distributed and the levees are fortified--and note that in this sample Austinization plan, no one's living in New Orleans or Bangladesh anymore, now, are they? So to hell with the levees.

What zero population growth advocates are really saying is, "I hate people, and I wish there were fewer of them." Well, join the club! I dislike people rather intensely myself. But I draw the line at telling them that not breeding with each other will fix a problem that it won't actually fix.

NOTE: Why, yes, astute reader; in fact I did rip this Austinization exercise off from P.J. O'Rourke's All the Trouble in the World--specifically, the chapter titled "Overpopulation: Just Enough of Me, Way Too Much of You." How clever of you to notice!

UPDATE: I had so many numbers wrong in this, it was MORTIFYING. Thanks to my excellent host Pixy Misa for noting the errors, which have now been corrected.

*Especially as yours is way more likely to be done CORRECTLY.