There are biased people on both sides, so it IS helpful to link arguments to sources without a direct dog in the fight. Here’s one:
cia.gov/library/publications/the-world-factbook/rankorder/2127rank.html
The CIA compiles a massive amount of information on nations. This link provides the total fertility rate of every major country on earth. It is a non-controversial GIVEN in the field of demographics that in the long run (centuries), an average 2.1 TFR is required for a population to remain constant. Virtually no wealthy industrialized nation on earth has a TFR over 2.1. Most are far BELOW that.
Demograpghers again widely agree that there is a natural TFR curve that occurs. Poor, uneducated agrarian societies tend to have high fertilty rates. Wealthy, urban and educated societies tend to have lower fertility rates. When a culture makes the transition from the former to the latter, the TFR decline seems to happen a generation or two AFTER the rest of the socio-economic transition ocurs. That transition period is one in which people still tend to have lots of babies, but the benefits of reliable nutrition, sanitation and medicine cause survival rates previously unheard of and population explodes.
This patten is NOT recent, nor dependent on contraception. Demographers have noticed this pattern of TFR trends way back centuries. (Yes, wealthy, urban, educated populations occurred before New York and LA were built!) Surprisingly, these wealthier families have tended for centuries to have smaller families (2-3 kids), even in cultures where contraception was unknown or considered reprobate.
Disclosure: now I’m moving beyond consensus into my own observations and research. Contrary to popular belief, earlier eras of humans were NOT morons because they lacked ipads and hybrid cars. In fact, we moderns are amazingly ignorant about our own bodies. In the 1850’s people either raised some livestock themselves at some point in their lives or had family who did. They had an inkling that mammals display symptoms when they are fertile. They wouldn’t have felt the need to name it (NFP), or call it a system or expect that their doctor would be able to help them learn it. It was part of what they’d call common sense! They were able to regulate their family sizes without needing to use medical technology to alter their bodies.
But as urbanization became a multi-generational way of life, some of that earthy common sense was lost. People forgot that our biology wasn’t all that different from animals. And when contraception came along and promised the ability to have sex, have no babies AND not have to keep the pants on so many days a month, it got people’s interest. Having eagerly adopted it, it only took a generation for people to forget altogether that they’d always had other ways of regulating family size. But the side effect of contraception is that it fundamentally makes having babies unrelated to sexual intimacy. This makes it MUCH less likely that the couple will seriously re-evaluate the need to avoid pregnancy and allows selfish reasons for being closed to life to go unexamined. (Believe me, you examine the reason when you are hot, bothered and frustrated - NFP). The end result of contraception (my assertion) is that cultures in which it is celebrated overshoot the low side TFR correction and remain at below-replacement levels indefinately.
Now back to the objective facts. The UN periodically updates global population projects. Their current projection has us headed upwards by billions more by the end of the century before leveling off. But underneath all their high tech models and impressive statistical calculations lies this HUGE fly in the butter (quote from UN Population Division):
"The second component of the projection model deals with countries once they have completed the demographic transition, and reached Phase III and potentially sub-replacement fertility. A time series model
is used for projecting fertility, assuming that in the long term the total fertility will approach the replacement-level of 2.1. " (Chapter V: Assumptions Underlaying the 2010 Revision)
What this techno speak means is that UN population projections ASSUME countries will rebound to TFRs of 2.1 relatively quickly. They do some academic hand-waving about why they settled on this assumption, but fail to acknowledge that such a thing has NEVER happened since the widespread adoption of contraception. Countries like Russia and Japan where contraception have been considered socially meritorious since the 1940’s have TFR’s down below 1.5 and there is no rebound in sight. Some Euro nations have recovered slightly from the low, to higher 1’s, but nobody has restored even a medium term trend at 2.1 other than occasional outlier years.
In short, there is serious academic reason to doubt the UN population projections that are based on assumptions in contradiction with observable facts on the ground in all developed nations. This is such a serious flaw in the methodology that I cannot believe that it is NOT political in origin. The Malthusian alarmists are so entrenched in the NGO community, that they aren’t interested in hearing that population stabilization is something that will take care of itself when equitable, just, stable and prosperous development occurs globally.
Instead, they are so hell-bent on speeding up the transition via promoting contraceptives, sterilization and abortions in the third world that they don’t care that the long term outcome is likely to be a population implosion.