According to the United Nations, the world's population
reached 7.3 billion in the middle of 2015. During the past 12 years alone, another one billion people have been added to the planet's population. It is forecast to increase by further billion over the next 15 years, reaching 8.5 billion in 2013. In 2050, it will pass the 9.7 billion mark, before topping 11.2 billion in 2100.