Over-population? Too Many People?

In 2011, the United Nations population division predicted a global population of 10.1 billion by 2100, an increase of nearly 50 percent from the earth's current population of 7 billion. But a new study out of Spain suggests those estimates may be way off—we're talking several billion people off.

Scientists at the Autonomous University of Madrid and CEU-San Pablo University say their estimates,  shows global population peaking in 2050 slightly above eight billion, and then falling back to 6.2 billion by the end of the century, the same as the total world population back in 2000.