World population hits 8bn, but falling births mean slower growth ahead

TOKYO -- The world population has reached 8 billion people, the United Nations estimates, crossing a new milestone as growth drops to a postwar low.

The U.N. declared Tuesday the "Day of 8 Billion," and the United Nations Population Fund called for "investing in people and making our societies inclusive, so that everyone is afforded a quality of life that allows them to thrive in our changing world."