The UN report, 2008 State of the Future, predicts that world population will drop to a level lower than today's by 2100. ...lot's of variables...only time will tell.
http://www.millennium-project.org/millennium/Global_Challenges/Gc-03.html
"The current world population of 6.7 billion is expected to reach 9.2 billion by 2050, peaking soon afterward at 9.8 billion and then falling to 5.5 billion by 2100, according to the UN lower forecast. Scientific breakthroughs over the next 50 years are likely to change these forecasts, giving people longer and more productive lives than most would believe possible today. Nevertheless, global population is changing from high mortality and high fertility to low mortality and low fertility."