How to estimate the future global population

[kthouz]

Hello everybody!
I have been reading about the evolution of population growth since 1950 till now. It had many factors such as development of technology, of medecine, ...
Now i want to calculate the future population growth let's say for example for 2050. In those readings i found also those estimations but my problem is what type of models to they use to predict it? For example i know the IPAT model that describe the impact of population on environment. As there exist that one, do there exist one that can predict the future population?

 

[CRGreathouse]

http://www.un.org/esa/population/publications/wpp2006/wpp2006.htm

 

[jim mcnamara]

I think the OP may want to work with logistic models as well.

kthouz - please do not double post - ask the same question in different forums. Thank you.