down

W: Professor Lee, the world’s population passed 6 billion on October 11, 1999, we are told. How long did it take to get there and how long will it take to reach 7 billion? And 10 billion?
M: The world’s population was 300 million at the dawn of the Christian era, which was the year AD I. In AD 1500, the world’s population reached 500 million. It took 304 years until 1804 to reach I billion, another 123 years until 1927, to reach 2 billion and then only another 33 years until 1960, to add another billion to reach 3 billion.
W: It’s very impressive that the recurring milestones of another billion added to the world’s population occurred quite quickly.
M: indeed. The world’s population reached 4 billion in 14 years in 1974; 5 billion in 13 years in 1987, and 6 billion in 12 years in 1999. Data suggest that the world’s population should hit 10 billion mid-way through the 21st century in the year 2054.
W: Do we have any good news except the terrifying data?
M: Well, as a matter of fact, the rate of growth is slowing and this slowing down is predicted to continue. Talking about rate of growth, the United States based lobby group calculates that 250 people are born each minute and 103 die, making a natural world increase in population of 147 per minute.
W: What about that in China?
M: In one minute, about 36 people are born and nine die, which leads to a net population gain per day of 39 096. If the current rate of population expansion continues, China’s present day population will double in size in 84 years.