I really meant to put this up about a month ago, but here we go. The UN recently released the World Population Prospects: The 2010 Revision. This predicts that the world's population will be 9.3 billion by 2050 and will eventually reach 10.1 billion by 2100 using their medium variant. The larger increase compared to the revision two years ago is predominantly from slower than expected fertility declines and lower HIV/AIDS mortality. The NY Times has a nice piece about the new projections and you can find the full report here (once it is all available). The press release provides a bit more detail without being overly long. There are two things especially interesting. First, the new projections are the first based on new Bayesian methods developed here at the UW by Adrian Raftery and others. The UW Today has a little article about the work here. Second, it is very timely for my work with Kathleen Beegle and Luc Christiaensen (both from the World Bank) on the effects of family planning programs in Ethiopia. We show that family planning programs are substantially more effective than what have been found in previous studies. There are two likely reasons for this. First, we focus on the effect by education level and show that the whole effect is concentrated among women with no education. Second, instead of looking at countries that are undergoing rapid economic growth and demographic changes, such as Indonesian or Columbia, we study a poor country where there is little economic growth. We find that the total number of children a woman has declines by 1.2 with access to family planning. The paper is available here.