by Robert S. McNamara

About the author: Robert S. McNamara was president of the World Bank from 1968 to 1981. In previous years he was United States secretary of defense and president of the Ford Motor Company.

For thousands of years, the world’s human population grew at a snail’s pace. It took over a million years to reach 1 billion people at the beginning of the last
century. But then the pace quickened. The second billion was added in 130 years, the third in 30, and the fourth in 15. The current total is some 5.4 billion people.

Although population growth rates are declining, they are still extraordinarily high. During this decade, about 100 million people per year will be added to the
planet. Over 90% of this growth is taking place in the developing world. Where will it end"

The World Bank’s...