Earth may be home to 1.3 trillion people by 2300 if couples do not stick to the two-child norm but world population could be around nine billion if they do, a United Nations report said in New York.

If fertility levels remain unchanged at today's levels, world population would rise to 44 billion in 2100, 244 billion in 2150 and 1.34 trillion in 2300, clearly indicating that the 'current high fertility levels cannot continue over the long term'.

Given the progress in extending life expectancy, the UN says, people could expect, on average, to live more than 95 years by 2300. Japan, which is the global leader in life expectancy today, is projected to have a life expectancy of more than 106 years by 2300.

If fertility stabilizes at two children per women, Africa's share of world population would almost double from 13 per cent now to 24 per cent in 2300 and Europe's share would come down sharply from to around six per cent from 12 per cent today.