U.N.: World's Population Is Aging Rapidly

The biggest problem for developing countries was high mortality rates, while wealthy countries faced falling birth rates and the decline in the working-age population, Secretary-General Kofi Annan said in a report to the U.N. Economic and Social Council. Annan said the population of all countries will continue to age substantially, but the increase will be faster in developing countries and social security systems that depend on workers to pay for those who are retired will be affected.

Such rapid growth will require far-reaching economic and social adjustments in most countries, he said. More people also are living in cities, the report found. It predicted that half the world will live in urban areas by 2007. In less developed regions, the number of urban dwellers will equal the number of rural dwellers by 2017, the report said. The United States is the most highly urbanized area of the world with 87 percent of its population living in cities. Latin America and the Caribbean followed, with 78 percent of the population living in urban areas, the report said.

In 1950 only two cities had 10 million inhabitants or more: the New York, Newark, N.J., area with a population of 12.3 million and Tokyo with 11.3 million. Today, the report said, 20 cities have more than 10 million inhabitants. The 10 cities with the biggest populations are: Tokyo with 35.3 million Mexico City with 19.2 million New York-Newark with 18.5 million Bombay, India, with 18.3 million Sao Paulo, Brazil, with 18.3 million New Delhi with 15.3 million Calcutta, India, with 14.3 million Buenos Aires, Argentina, with 13.3 million Jakarta, Indonesia, with 13.2 million and Shanghai, China, with 12.7 million.

The report also highlighted the aging of the population, saying there were 600 million people over the age of 60 in 2000, three times the number in 1950, and that figure was expected to triple again over the next 50 years to around 2 billion elderly. The average number of children a woman gives birth to, meanwhile, declined from five around thirty years ago to three by the beginning of this century, the report said.

Mortality declined sharply during the 20th century, except in Africa, which has been hard hit by the AIDS epidemic, Annan said. Overall, the world's population reached 6.5 billion in 2005 and could stabilize at 9 billion just after 2050, Annan said.