7 Billion Humans in 2011 | National Geographic Magazine

By the United Nations estimates, the world’s population is now over seven billion. The first billion people accumulated over our entire history until the early 1800s. The second took an additional 120 years. In the last 50 years, we have doubled, going from three billion in 1959 to four billion in 1974, five billion in 1987 and six billion in 1998. This is no historical precedent for this population increase.