The possibility that the world’s population will climb to 11 billion by the end of the century is gaining traction now that demographers are using probability methods for their projections. A paper published online on Thursday in the journal Science details new methodology that shows that most of the world’s anticipated growth is in Africa, where population is projected to quadruple from about 1 billion today to 4 billion by 2100. “For the last 20 years, prevailing opinion was that world population would go up to 9 billion and level off in the middle of the century and maybe decline,” said Adrian Raftery, one of the paper’s lead authors and a professor of statistics and sociology at the University of Washington. “Population is going to keep growing. We can say that with confidence.” Not only with confidence but with an exact percentage. There is a 70 percent probability that world […]