World population: seven billion today, how many tomorrow?

The number of people in the world is increasing rapidly, raising concerns about overpopulation. Demographers are projecting that growth will continue for several more decades, but at a steadily slower pace. As Gilles Pison explains here, the world population is set to rise by a further one to four billion over the next century, but should level off thereafter.

The world population will top 7 billion this year (2011) and should reach 8 billion by around 2025. Population growth is slowing down, however: after peaking at 2% fifty years ago, annual growth has fallen by almost half (1.1% in 2011) and should continue to decrease until the population levels off at around 10 billion one century from now. One of the majorchanges in future decades will be the exceptional population growth in Africa. The continent’s population, including NorthAfrica, could quadruple over the next century, rising from800 million inhabitants in 2000 to 3.6 billion in 2100.