Population Stability

In response to Richard, I was honestly not trying to make an argument, just asking for data.  But the reasons for my interest in seeking the data are probably obvious.  So, I'll defend the interest.  It seems to me to be obviously the case that at some point population stability becomes an important human issue.  That is, while the blessings of ever more children and all that are fine, I think it has to be conceded that there is a finite carrying capacity for the planet.  Whether we are currently close to the limits of that capacity is also a separate (and irrelevant) question, as long as some finite limit exists.  (I happen to think we are close to it, but that's neither here nor there.)  We'll either reach that limit by hitting some break point that will introduce increased mortality, or we'll avoid it by achieving population stability. 

Now the Church does not deny the legitimacy of the goal of population stability per se, it just limits the acceptable means of accomplishing that goal to abstinence (or sex during infertile periods in the woman's cycle).  If no society has ever successfully achieved population stability through this method, I think that's interesting information.  It suggests to me that the Church may be committed to the reality of a world with dramatically increased mortality.  And I guess I'm wondering whether such a world is really consistent with any plausible account of human flourishing.  Excessively low birth rates in the west, no doubt achieved with the help of artificial contrception, seem irrelevant to this point.  I'm not trying to make some grand defense of every conceivable use of contraception; I'm just considering the implications of Grisez's (and the Church's) position that contraception is always impermissible and that the question of population stability is absolutely irrelevant to the moral equation.