From the Editor's Desk:

Human population Milestones by the billions

The population in 1 A.D. was 170 million; today, it’s 7.9 billion, according to the museum, which worked with Population Connection, the U.N.’S World Population Prospects, Worldometers and NASA on the project. As it follows the population explosion, the American Museum of Natural History points out specific events that encouraged population growth, such as the advent of farming, travel and trade on the Silk Road, and the development of modern medicine.

At the dawn of agriculture, about 8000 B.C., the population of the world 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 one billion, the second billion was achieved in only 130 years (1930), the third billion in 30 years (1960), the fourth billion in 15 years (1974), and the fifth billion in only 13 years (1987). During the 20th century alone, the population in the world has grown from 1.65 billion to 6 billion. In 1970, there were roughly half as many people in the world as there are now. It has also been estimated that a total of approximately 117 billion people have been born since the dawn of the human species, making the population currently alive roughly 7% of all people who have ever lived on planet Earth. The United Nations projects world population to reach 10 billion in the year 2050s.