"The United Nations released its first projection of the world's population in 2300 on Tuesday -- forecasting a rise from the current 6.3 billion people to around 9 billion.
But the U.N. Population Division said a small shift in fertility levels could have an enormous impact on the population of planet Earth.
The 9 billion estimate is based on the two-child family, but as little as one-quarter of a child less or one-quarter of a child more per family would result in world populations in 2300 ranging from 2.3 billion to 36.4 billion, it said."
"The report, ``World Population in 2300,'' also foresees far more older people.
The median age of the world today is 26 years. By 2300, it will nearly double to 50 years, Chamie said.
Similarly, the world population of people aged 60 and over will jump from 10 percent to 38 percent by 2300 -- and the percent over 80 will rise from just 1 percent today to 17 percent over the next 300 years, he said."