The first United Nations population forecast came in 1958, when the world population sat just under 3 billion. Many were skeptical of the UN experts’ predictions that the population would double to roughly 6 billion by the year 2000, but their forecasts proved remarkably accurate. In this brief video, Professor Hans Rosling of the Karolinska Institute looks back at how UN population outlooks have played out in the past, and charts new predictions for the human population between now and 2100.