I had a similar "overpopulation myth" discussion with a rather extreme environmentalist (80 year old) friend (George) of mine at the coffee shop earlier this week. He is convinced that the world is greatly overpopulated at this time and that it is just getting worse and worse. He is also rather socialist in his views of funding all sorts of government programs by severely taxing the "rich".
I argued that the world's governments and societies will have many more problems in coming years due to not enough young (working) people rather than too many young people.... The more socialist societies will have even more problems because they require many more working people to pay for all of the "free" government programs. Less young (working) people will translate to higher taxes and less money for social programs (e.g. see Greece, and others).
I think that you will find this web site to be interesting. There is a lot of interesting "fertility rate" and population info here. It appears that the source for all (or most) of the data is the CIA (Central Intelligence Agency) Fact Book, accurate as of July 2012... probably a rather reliable source. The generally accepted "replacement fertility rate" is and average of 2.1 children per woman. Fall below 2.1, and your country's population is not replacing itself (except, perhaps by immigration). You will see from the large bar chart that of the 222 countries in the world, 106 countries are below the replacement rate of 2.1 children. You will see that essentially every single large, modern, industrialized country is currently below the replacement level of 2.1 children. I believe that I read somewhere else on that web site that 48% of the world's population lives in a country which is below the 2.1 child replacement rate. This doesn't exactly agree with the fear and calamity predictions of the "over-population people".
By the way... You will also notice from the bar chart that some major, modern, industrialized countries is in serious jeopardy of essentially disappearing from the world stage due to their extremely low fertility rates. Some countries among them include Germany (1.41), Japan (1.39), Poland (1.31), South Korea (1.23), Taiwan (1.10), Hong Kong (1.09) and Singapore (0.78 - Yikes!). The USA is at 2.06 and China is at 1.55.
I probably isn't necessary to say... But I was not able to change George's mind on the threat myth of over-population.
That is an excellent chart, Ed. I could not find the US though. Did you see it? Also, I thought I heard that Japan
is less than 1 child per couple.