A burgeoning world population.

• Author: Larsen, Janet
• Position: Eye On Ecology

DURING 2004, 133,000,000 people were born and 57,000,000 died, expanding world population by 76,000,000. This excess of births over deaths was concentrated in developing countries, which added 73,000,000 compared with 3,000,000 in the industrial nations. World population, growing by 1.2% annually, should reach 6,400,000,000 by the end of 2005.

Just over 1,000,000,000 of the Earth's inhabitants live in the industrialized nations of Europe, North America, Oceania, and Japan, where populations are expanding, on average, 0.25% a year. Meanwhile, the globe's other 5,200,000,000 people live in the less developed countries, where populations are rising 1.5% annually--six times as fast.

Six countries account for half the annual increase, and all of these but the U.S. are in the developing world: India (21%), China (12%), Pakistan (five percent), and Bangladesh, Nigeria, and the U.S. (four percent each).

China--long the world's most populous country--is likely to cede its top position to India by 2035. In 1968, China's annual growth rate peaked at 2.7%; by 2004, it had slowed to 0.7%. Its population, now at 1,300,000,-000, is projected to top out at 1,450,000,-000 in 2031. India's population, which is growing by 1.5% annually, is not expected to crest until 2065 at 1,560,000,000.

It took from the beginning of human existence until early in the 19th century for our ranks to swell to 1,000,000,000. We reached the second billion 123 years later, in 1927. Since then, however, the milestones have arrived much quicker: World population hit 3,000,000,000 in 1960; 4,000,000,000 in 1974; 5,000,000,000 in 1987; and 6,000,000,000 in 1999. We likely will hit 7,000,000,000 by 2013.

There are 17 countries where women bear an average of six or more children. All but two of them, Afghanistan and Yemen, are in Africa. Women in Niger, Somalia, Angola, Uganda, Yemen, and Mali have, on average, seven or more offspring. At this rate, each of these poverty-stricken countries faces another doubling of its population within the next quarter-century.

In Europe, however, women check in with an average birth rate of 1.4. Worldwide, there are more than 60 countries with fertility at or below replacement level. The smallest families today are in the Eastern European countries, Spain, and Italy, where women have just one child on average. Populations in these locales already are dropping or are set to decline by the end of this decade.

The number of children a woman bears...