I don't know how you even begin to measure "government competence," but 1) I see no particular evidence that government is more of less competent than it was 50 years ago (perhaps it's a bit more competent if anything) and 2) the reasons for incompetences seem, at best, VERY loosely related to size of population.

I'm new to your blog. I'm particularly interested in the aging population. My blog (www.genplus.blogspot.com) explores, among other things, the effects of aging on the workforce. My business is devoted to helping 50 plussers find employment in an economy that values youth even as it ignores a looming employment crisis.

In the US, 78 million Boomers turn 50 within the next 5 years, but in China, it is estimated that 440 million turn 50 within the next five years. I agree with you -- increasing the birthrate is not only unlikely, but only viable in theory, not practice. In China, for example, the elderly are working the land until they are incapable of physically working any longer because the youth are leaving for non-agrarian jobs in the cities and no longer available to support their aging relations. China is not prepared at all for the aging crisis on their hands and its government is belatedly looking at how to handle the next 25 - 30 years. The US is similarly unprepared. The aging population is the white elephant in the room and with a generally aging world, the elephants will eventually be noticed, but far too late to avoid the damage. I agree with your comments 100%. Great articles.

In response to: I do think it is plausible that the net effect on social welfare of a greater population in that country would be negative (why else is the Chinese government enforcing such an unpopular policy?)

AS far as I know there isn't a convincing evidence to support that the Chinese policy is helping them and also it is no surprise to me that in many cases politicians enforce unpopular policy which clearly is detrimental to the society. In case of China it one-child-only policy is clearly a social engineering experiment. Has it really helped them in a demonstrable/verifiable way? Is it critical to a prosperous China?
The one negative thing that I did come across in case of China's population control measures was in NPR. It was about the female-to-male ratio, which is declining steadily (rapidly?) in China (due to abortion after identifying the gender of the fetus?) Similarly, in some parts of India there are reasons to worry that the ratio might fall. Would this not result in more crimes (against women or among men) in the future?

In general, it appears to me that it is hard to predict how population control measures might help and it also depends on what the population control measure is and how it is implemented. Even if all this can be worked out there are potentially hidden dangers that right now we are not able to perceive.

Female education/empowerment leading to lowering the birth rate is comforting to hear though (that probably is a good way to control population in India and China for e.g. and retaining the ratio).

I did like to qualify two factors that influence the question "Is population growth good or bad?"

One, nature of income of the population and two, nature of the government.

If you have an income generating class and a government that does its stated functions (comparatively, population will not be seen as a problem.

But an income generating class with a dysfunctional government will result in the poor (incomeless) being seen as a problem and increase of poor is seen as a problem.

In a society that doesn't generate much income and which has a dysfunctional government, population will come to be seen as the major problem.

In a society with less of income generation but more of good governance, welfare payments will come to be seen athe main issue.

One interesting question is how changing technology changes the impact of having a bigger vs. smaller population. A pretty obvious example is in warfare--WW1 style warfare really benefitted from a large population of soldiers, even if they weren't especially well equipped or trained. It looks to me (as a nonspecialist!) like this is no longer true--you do better with a smaller population of better educated soldiers who are also better equipped. (Doesn't the US Army pretty-much refuse to take recruits with IQs of less than 90 or so?)

I wonder whether increasing automation will have this impact in broader economic terms--a big population may end up being more mouths to feed, but not really more hands to work. Or perhaps it works the other direction, and more automation means a growing economy that can find work for anyone who wants it, even with a growing population.

That's an interesting last paragraph. It's like asking, "Why did Imperial Rome Fall". Answer, "It got too big to govern effectively and efficiently" (although there might be additional causes) and so the rest is history.
My concern is not so much in terms of CO2 emissions and the like, but the depletion of available O2 for breathing. We're destroying or developing, depending on which side of the equation one is standing on, the oxygen production equipment at a geometric rate. There appears to be a general depletion of % O2 available for breathing by burning fossil fuels that's where the O2 comes from in the CO2 resultant equation. If it is kept up, the percent O2 available will drop below 19.8% which is what is required to sustain life. Currently the level is around 20.8%

Hopefully we'll be able to get this under control before we suffocate. Perhaps Buckminster Fuller was right, this is spaceship Earth.

Posner writes "Although historically the net social benefits of technological progress have been positive, there is no compelling theoretical reason to expect this always to be the case." Technically, that's true, just like it would also be true to say "...there is no compelling theoretical reason to expect that this trend should not continue indefinitely."

To my ear, Posner wants to convince us that we should ignore the prevailing trend of human history, that technological progress and population growth lead to increased general welfare, because he can think of a couple of anecdotal examples where increased technology might in the future allow a terrorist to be more destructive. But for every example there is another example that points to the opposite trend - What about vaccines that render smallpox impotent? What about advances in monitoring technology that make it easier to identify terrorists? etc. If there is real evidence of any trend shift, then we can consider it fairly.

The same argument applies to the "genius" hypothesis, which Becker surprisingly agrees with. If the net effect in history of more geniuses was a destructive one instead of a beneficial one, wouldn't the human population been wiped out long ago? The most likely effect is that more geniuses will in the future be a good thing, just like they have traditionally been (I personally think the contributions of geniuses are somewhat overestimated, although it will be hard to make that case in the presence of our phenomenally genius and phenomenally productive blogger hosts!)

In the absence of compelling evidence to support the idea that trends in the future will be wholly different from how they have been in the past (and to me "terrorists are becoming more powerful" is not compelling enough), the more probable result is that they will instead be roughly the same.

You might choose to be overly cautious because you want to protect against the worst-case scenario, but please realize that there are economic costs to this strategy.

Posner writes: "Increases in population, and concomitant increases in economic activity, crime, demand for medical services, and so forth make the job of government more difficult. What seems to be an incipient crisis of competence in the U.S. government may be at least distantly related to the doubling of the U.S. population since 1948."

I say to Posner, "nice try." Whether one agrees or disagrees with the political philosophy of the current administration, it has now become clear that it has appointed hacks and/or ideologues to key positions who have flubbed their jobs because of either their incompetence or their unwillingness to accommodate their views to reality. Incompetent government run by hacks is an old political story, unrelated to population. There is an ebb and flow in politics, and the ebb that brought the current group to power had consequences. I predict that voters, for the first time in at least a few years, will begin to care about competence again.