Here's a graph for anyone who is interested in it;
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Graph shows future population based on three different levels of fertiltiy.
High = 2.35 children per woman
Low = 1.85
On average developed countries have a fertility rate of 1.6. Some European countries are at 1.2 (yet stupid morons rant about the dangers of immigration).
Developing countries have a fertility rate of 3.2 on average.
The prophecies of doom about the world consuming itself as developing countries become developed ignore the simple fact that as they do so their birth rates will fall just as ours did. Chiona already has a lower fertiltiy rate (1.8) than the USA (2.1).
Population will rise from where it is today, probably to around 10 billion (which is quite sustainable), and will then start to fall around 2100, with a period of very little population change in the second half of this century.
Reports of us making ourselves extinct are rather premature... we have died out from over-population several times acroding to Malthus and various doom-mongers from the 18th Century doiwn to the '70's where as a school kid I read (in school books) that 'we were doomed'.
Worst thing is if we act as though its hopeless, it will be more hopeless than it actually is.
http://www.overpopulation.com/faq/basic_information/total_fertility_rate/