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Earth Sense: Megacities bring positives, but also dangers
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As we prepare to start a new year, we can also expect to find ourselves in a changed world. The old dream of living off the land in a quiet cottage is giving way to an ever-increasing worldwide trend: the megacity.

World population passed the 7,000 million (7 billion) mark a year ago. Not surprisingly, the huge increase that happened during the past 30 years was most noticeable in the growth of cities.

Atlanta, with about 500,000 people plus its many satellite towns, conveys a pretty good idea of what a megacity is like. But that area is dwarfed by what’s emerging in the developing world, particularly Asia. The United Nations Task Team on the Post-2015 Agenda reports that more than 70 percent of urban residents today are in developing countries. Every day adds an average of 187,066 new residents to the world’s cities.

Population counts are difficult, but according to the U.N., the biggest city in the world is now Shanghai, China. With a metro population of more than 17 million and an area of 2,500 square miles, it dominates the coast of the East China Sea.

Following on the list are Mumbai, India and Bejing, China, with 12 million people each. You’ve heard of those. But a name that probably wasn’t mentioned in high school is Chongqing, China. Its extended region on the upper Yangtze River is home to 30 million inhabitants, one-third of whom lives in metro Chongqing.

In Africa, the Nigerian National Bureau of Statistics reports just under 10 million residents for metropolitan Lagos, Nigeria. Similar rising population trends are found in Lima, Peru (6 million) and Bogota, Colombia (7 million).

This isn’t an altogether bad trend, as cities are the centers of technological innovation and new solutions, as well as cultural heritage. But the concern expressed by the U.N. is well placed. Most of the world’s megacities are located on sea coasts, with some exceptions like Mexico City and Sao Paulo. This exposes the population to water-borne hazards from hurricanes.

Most earthquake-producing faults are also located along coastlines, adding the risk of quakes, tsunamis, volcanic eruptions and, more recently, rising sea levels due to climatic change. Man-made problems of air and water pollution as well as urban flooding will ensure that we are going to see Calcutta, India, and Manila, Philippines, in the news again soon.

The explosion of world megacities guarantees a full international agenda for 2013.

Rudi Kiefer, Ph.D., is a professor of physical science and director of sustainability at Brenau University. His column appears Sundays and at

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