Global population, as a result, was doubling every generation. Today, women on average have just half the number of children they did in 1972. In 61 countries, accounting for 44 percent of the Earth's population, fertility rates are now at or below replacement levels. That doesn't mean the Earth's population will fall anytime soon. Thanks to the high fertility rates of the past, a large percentage of the world's population is still of childbearing age.
Life expectancy is also up.
Globally, the average life span has jumped from 49.5 years in 1972 to more than 63 years. Consequently, according to projections by the United Nations, the world's population will slowly increase at an average rate of 1.3 percent a year during the next 50 years, and it could decline by midcentury if fertility continues to fall. So there is a new problem for mankind. Next year, for the first time in history, people over 60 will outnumber kids 14 or younger in industrial countries. Even more startling, the population of the Third World, while still comparatively youthful, is aging faster than that of the rest of the world.