Did you know? China is planting a belt of trees to protect land from the expanding Gobi Desert. This Great Green Wall is projected to extend some 4,480 kilometers (2,800 miles), stretching from outer Beijing through Inner Mongolia (Nei Monggol). Unfortunately, recent pressures to expand food production appear to have slowed this tree planting initiative. For more information view the text and data in Chapter 8 of Plan B 4.0: Mobilizing to Save Civilization.
Chapter 9. Redesigning Cities for People: An Urbanizing Species
Agriculture set the stage for the formation of cities. Advances in agricultural productivity that came with the beginning of irrigation some 6,000 years ago in the fertile soils of the Euphrates Basin freed up people to create the first cities. Several thousand years later the Industrial Revolution gave cities another boost. The early factories required a concentration of workers not possible in rural communities. The evolution of cities is tied to advances in transport—initially ships and trains, then motor vehicles. It was the internal combustion engine, combined with cheap oil, that provided the mobility of people and of freight that fueled the phenomenal growth of cities during the twentieth century.
Although the first cities were formed several thousand years ago, the urbanization of world population has been concentrated in the last half-century. In 1950, an estimated 750 million people lived in cities. By 2000, this number had climbed to 2.9 billion, nearly a fourfold increase. The United Nations predicts that by 2050 more than two thirds of us will be living in cities.4
Cities have been at the center of the evolution of modern civilization. It is probably not a coincidence that the first written language apparently evolved in the earliest cities. At the beginning of the Christian era, there were already several great cities: Athens, Alexandria, and Rome. A list of the world's 10 most populous cities in selected years since then tells us much about history, the rise and decline of civilizations, the growth and disintegration of empires, industrialization, and, more recently, wide population growth variations among countries. (See Table 9-1.)
In the year 1000, the world's 10 largest cities were widely dispersed throughout the Old World. But by 1900, a century after the Industrial Revolution began, nearly all the large cities were in the industrial west. In 2000, after a century of record population growth—most of it concentrated in the Third World—7 of the top 10 were in developing countries.
People living in cities impose a disproportionately heavy burden on the earth's ecosystems simply because so many resources must be concentrated in urban areas to satisfy residents' daily needs. Vast quantities of food and water must be moved into cities, and the resulting concentration of human waste must then be dispersed.
The industries that take advantage of the labor force in cities require raw materials. These, too, must be transported, often over long distances. Finished goods must then be shipped to markets within the country and, as globalization proceeds, other parts of the world.
The early cities relied heavily on food and water resources in the surrounding countryside. But today cities often depend on distant sources even for such basic amenities as food and water. Los Angeles, for example, draws much of its water supply from the Colorado River, some 970 kilometers (600 miles) away. Mexico City's burgeoning population, living at 3,000 meters, must now depend on the costly pumping of water from 150 kilometers away and a kilometer or more lower in altitude to augment its inadequate water supplies. Water-starved Beijing is contemplating drawing water from the Yangtze River basin nearly 1,500 kilometers away.5
Food comes from even greater distances, as is illustrated by Tokyo, whose population exceeds that of the world's 10 largest cities in 1900 combined. While Tokyo still depends for its rice on the highly productive farmers in Japan, with their land vigorously protected by government policy, its wheat comes largely from the Great Plains of the United States and Canada and from Australia. Its corn supply comes largely from the U.S. Midwest. Soybeans in Tokyo come from the U.S. Midwest and the Brazilian cerrado.6
Many cities today are linked more tightly to each other than to their own countryside. Air travel ties cities together, often making it easier to get to a city in another country than to the more remote rural regions within the same country. The trading of goods and services now occurs proportionately more among cities than between cities and the surrounding countryside.
It is widely assumed that urbanization will continue. But this is not necessarily so. If the world is facing water scarcity, the availability and cost of transporting water over long distances may itself begin to constrain urban growth. Beyond this, a future of water scarcity is almost certainly also a future of food scarcity, since 70 percent of all the water pumped from underground and diverted from rivers is used for irrigation. (See Chapter 7.)7
In a world of land and water scarcity, the value of both may increase substantially, shifting the terms of trade between the countryside and cities. Ever since the beginning of the Industrial Revolution, the terms of trade have favored cities because they control capital and technology, the scarce resources. But if land and water become the scarcest resources, then the people in rural areas who control them may have the upper hand. If so, the terms of trade could even reverse urbanization in some situations.
Beyond resource shortages, the evolution of the Internet, which is changing how we think about such basic parameters as distance and mobility, could also affect urbanization. The availability of e-mail and the potential for telecommuting may reduce the advantages of living in the city. Cultural amenities, such as museums, once found only in cities may now be toured over the Internet, further diminishing the draw to urban life. Internet commerce, offering more options than any shopping mall, may also lessen the role of urban centers as supply sources for a wide variety of goods and services.
|Table 9-1. Population of World's 10 Largest Metropolitan Areas in 1000, 1900, and 2000|
|Source: Molly O'Meara Sheehan, Reinventing Cities for People and the Planet, Worldwatch Paper 147 (Washiington, DC): Worldwatch Institute, June 1999), pp 14-15, with updates from United Nations, World Urbanization Prospects: The 1999 Revision (New York: 2000).|
4. United Nations, op. cit. note 1.
5. Los Angeles from Sandra Postel, Last Oasis, rev. ed. (New York: W.W. Norton & Company, 1997), p. 20; Mexico City from Joel Simon, Endangered Mexico (San Francisco, CA: Sierra Club Books, 1997); Beijing from "State to Minimize Adverse Effects of Water Diversion," China Daily, 8 March 2001, and from "Water More Precious than Ever," China Daily, 14 March 2001.
6. U.S. Department of Agriculture (USDA), Foreign Agricultural Service, Grain: World Markets and Trade, and Oilseeds: World Markets and Trade (Washington, DC: various issues).
7. Figure of 70 percent from I.A. Shiklomanov, "World Fresh Water Resources," in Peter H. Gleick, ed., Water in Crisis: A Guide to the World's Fresh Water Resources (New York: Oxford University Press, 1993).
Copyright © 2001 Earth Policy Institute