Sociology in Global Perspective

The chart visually presents two thousand years of world population growth and introduces a "population doubling time" theory.

From the textbook: chapter 4, p. 2

"Ten thousand years ago, the total world population was only about 8 million people — less than the population of the Chicago metropolitan area today! Before then, the population had grown only slowly and with frequent setbacks. But when people began settling into permanent communities, around 8,000 B.C., populations began an upward ascent which continues today.

By the time that Jesus was born in Bethlehem there were about 250 million people alive. It took 1,650 years for the population to double from 250 million to half a billion in 1650. About 200 years later, around 1850, world population doubled again to total a billion people. This is what demographers call doubling time — the number of years required for a quantity to double at a fixed annual growth rate. We reached two billion in 1930 — a doubling time of only 80 years. Forty five years later, in 1975, we were at four billion."

© Lynn Nelson
© Digital Text Plus