Although the US Census Bureau says it'll happen sometime in March, the United Nations says the world's population will reach seven billion sometime today, creating new challenges for generations to come. The rate of human growth is finally slowing down, and Earth's resources are sufficient for three billion more, depending on technology and distribution. But will all those people be able to urbanize and increase their consumption and waste without creating famine, poverty and an unhealthy environment? We look at what might be in store for the United States, developing countries including China and India and the fastest-growing part of the world, sub-Saharan Africa.
Andrew Revkin, New York Times
Joel Cohen, Rockefeller and Columbia Universities
Deborah Seligsohn, World Resources Institute
Patrick French, author