At the dawn of agriculture, about 8000 B.C., the World Population was approximately 5 million. Over the 8,000-year period up to 1 A.D. it grew to 200 million, with a growth rate of under 0.05% per year. A tremendous change occurred with the industrial revolution:
Whereas it had taken all of Human history until around 1800 for World Population to reach the first billion, the second billion was achieved in only 130 years (1930), the third billion in less than 30 years (1959), the fourth billion in 15 years (1974), and the fifth billion in only 13 years (1987).
World Population is currently (2017) growing at a rate of around 1.11%per year. The current average population change is estimated at around 80 million per year.
The annual growth rate is currently declining and is projected to continue to decline in the coming years. Currently, it is estimated that it will become less than 1% by 2020 and less than 0.5% by 2050.
This means that World Population will continue to grow in the 21st century, but at a slower rate compared to the recent past.
World Population has doubled (100% increase) in 40 years from 1959 (3 billion) to 1999 (6 billion). It is now estimated that it will take a further 39 years to increase by another 50%, to become 9 billion by 2038.
The latestUN projections indicate that World Population will reach 10 billion persons in the year 2056.