Population growth estimates pop up once in a while. Most of the ones that I have seen tend to agree that population growth is slowing down.
Here is one reference from Nature.
http://www.nature.com/nature/fow/010802.html
"The latest study, presented by Lutz et al. in this issue, reckons an 85% chance that global population will peak before 2100, and predicts with 60% certainty that this peak will be less than 10 billion, compared with a population of 6 billion today. They even give an outside chance, 15%, that there will be fewer people living at the end of the century than are alive now.
Their results are notable not just for the relatively low figures projected, but also for the rigorous probabilistic analysis that accompanies them. Whereas the United Nation estimates present just four possible outcomes (constant, high, medium and low), the figures presented by Lutz et al. include specific chances of a particular scenario occurring on a specific date. This graphically illustrates the confidence (or otherwise) of predictions further into the future.
To arrive at their conclusions, the team combined two forecasting techniques 'time series extrapolation', a statistical analysis based on known figures, and 'expert judgement', whereby key parameters are estimated taking into account foreseeable events such as disease, war and fertility trends.
Apart from the lower total population figure estimated (8.8 billion by 2050, compared to 9.3 for the UN's medium estimate, 2000 revision), Lutz et al. analysis reveal some interesting trends. Population decline in developed nations is expected to accelerate, with the European part of the former USSR expected to lose 20% of it population by 2050. Such declines lead inevitably to ageing populations, and half of all people living in Japan at the end of the century are predicted to be over 60 years old."
