A world population of 7 billion in 2011... and how many tomorrow?
For thousands of years, human beings were a rare species and their numbers grew very slowly. By around 1800, the population began to increase rapidly, starting in the rich countries and then, from the twentieth century, in the rest of the world.
What are the reasons for this growth, and what factors are affecting the population today? Will the world population level off in the years to come? How will the world be populated in the future? [...]