Last week, the UN released updated population figures and projections. I just had a chance to go through them and the great key findings document (PDF, 1MB) that accompanies them.
But before I dive in, how accurate are these projections? What kind of track record do UN demographers have? The most comprehensive answer I could find was Nico Keilman’s 2001 paper which Hans Rosling refers to in this video. He notes that in 1958, when the UN projected the population in 2000 to be ~6 Billion (it was then 42 years into the future) they ended up being out by less than 5%. The short answer is: these projections are pretty good.
There are 7.3 billion people alive today and while the world’s population continues to grow, it’s growing more slowly than in the past. We can expect to see an additional billion people added over the next 15 years, and about a billion more 10 years later, reaching a total population of 9.7 billion in 2050.