Every second five babies are born in the world and only two people die. That makes a net gain of three new people every second. At this rate, the world population will double every 40 years and would be 12 billion in 40 years, 24 billion in 80 years, and more than 48 billion in 120 years. However the United Nations estimate that world population will stabilize at 12 billion in 120 years, citing that effective family planning will result in a universally low birth rate. Education plays a key role: almost half of the 6 billion people are under age 25.