The world gains a million people every four and a half days and many are raising concerns about overpopulation and its possible ramifications.
Overpopulation is something that has happened to humans gradually, said Alan Weisman, who is the author of the book, "Countdown: Our Last, Best Hope For a Future On Earth," which examines the question.
According to Weisman, the world’s population in 1968 was 3.5 billion people, and the “population explosion” was a term of concern then. Today, there are 7.2 billion people living on the planet.
As part of his research, Weisman traveled to 21 countries and talked with the world’s...
