Table of Contents

Introduction

Fertility

Mortality

Migration

Population Size and Growth

Population Composition

Population Distribution

Population Growth Issues

Concern About Population

Conclusion

Suggested Resources

References

Related Publications

Population: A Lively Introduction

Population Distribution

• World Population
• Figure 9: Changing Distribution of World Population, 1950, 1998, and 2050
• U.S. Population Distribution
• Figure 10: Population Growth or Decline in U.S. Counties, 1990 – 1997

Where do the world's 6 billion inhabitants live? Demographers answer the question by keeping tabs on the distribution of population by world region, by country, by province or state within countries, by urban and rural area, and by neighborhood within cities. The geographic distribution of population is determined by fertility, mortality, and migration.

World Population

Population is unevenly distributed among the world's regions and, because some regions are growing much faster than others, the geographic distribution of population is becoming more unbalanced. The developing regions encompassed 68 percent of the world population in 1950 and 80 percent in 1998 (see Figure 9). And, according to United Nations projections, these regions will contain 88 percent of world population by 2050 and 89 percent by 2100.⁶⁵

Fertility is the primary cause of the uneven population growth rates among world regions, but migration does play a role. Indeed, international migration is at an all-time high in the 1990s. Migrants move from the less-affluent developed nations to the more-affluent ones (for example, from Portugal to France) and from the poorer developing nations to relatively prosperous ones (from Colombia to Venezuela), as well as from developing countries to developed countries (from Mexico to the United States, for example). About 1 percent of the developing world's population growth—just the growth, not the population itself—is absorbed by the developed nations through migration.⁶⁶

A major feature of population redistribution within developing countries is urban growth. The urban population of these nations rose from 304 million to 1.8 billion between 1950 and 1996.⁶⁷ About 60 percent of this urban growth was caused by natural increase among current city dwellers (both those born in the city and those who migrated there). The rest of the urban growth came from rural-to-urban migration.

One conspicuous consequence of this growth is the proliferation of jumbo-sized cities in developing countries. In 1950, Shanghai and Buenos Aires were the only cities in the developing world with more than 5 million inhabitants. By 2000, the UN projects there will be 35 such cities, including 16 with more than 10 million inhabitants.

Rapid population growth quickly overwhelms the public services and housing supply in these cities, not to mention the supply of jobs. Millions of residents cope by building makeshift shelters on open land and by trying to make a living on the streets, often creating their own informal economic and social systems. Gigantic shanty-towns have sprung up around major cities throughout the developing world, a testament to the explosive growth in these cities.

U.S. Population Distribution

Like world population, the U.S. population is unevenly distributed. More than half the U.S. population lives within 50 miles of a coastal shoreline.⁶⁸ Mountains, deserts, and long distances, in conjunction with unrelated economic factors, have limited population growth in many parts of America's middle section.

Population density, the number of inhabitants per square mile, ranges from 1,085 in highly urban New Jersey to one in Alaska. Many sections of America's heartland are sparsely populated. In 1996, Wyoming had only 481,000 inhabitants—fewer than Denver and 25 other U.S. cities.⁶⁹ Yet the Midwestern states of Illinois, Ohio, and Michigan rank sixth, seventh, and eighth, respectively, in population size.

The South is the most populous region of the country, with 35 percent of the population, followed by the Midwest (23 percent), the West (22 percent), and the Northeast (19 percent).

The distribution of the U.S. population is always changing because of geographic differences in natural increase and net migration. The total population increased by 7.6 percent between 1990 and 1997, but the situation varied across the country (see Figure 10). Counties in the nation's middle section, from the Great Plains states down to Texas, suffered the highest percentage of loss, while those in the West (especially the Rocky Mountain states) and the Southeast grew the fastest.

International and internal migration are the main determinants of population redistribution in the United States, but natural increase also plays a role. Utah, which has one of the highest fertility levels and longest life expectancies of any state, increased its population by 18 percent during the 1980s solely because of natural increase. Net migration was negative during the decade—more people moved out of Utah than moved in. In the 1990s, Utah became a magnet for interstate migrants, but it still gained more people from the excess of births over deaths than from net in-migration.

International migrants settle disproportionately in certain states and communities, often close to their ports of entry into the United States. Indeed, the U.S. Immigration and Naturalization Service reports that about 70 percent of all newly arrived immigrants intend to live in one of just six states: California, Texas, New York, New Jersey, Florida, and Illinois.

Within the United States, migrants tend to follow several long-established migration streams. The first stream flows from the eastern seaboard states westward, a demographic process that has occurred since colonial times and that ultimately pushed the American frontier out to the Pacific Ocean. The second stream runs from rural to urban areas. In 1910, 38 percent of the U.S. population lived in metropolitan areas. By 1996, about 80 percent of the U.S. population lived in metropolitan areas—and 56 percent in metro areas with 1 million or more inhabitants.

A third major migration stream, which accelerated during the Great Depression of the 1930s, led from economically depressed areas in the South to the cities of the Northeast and North Central states. This Southern exodus brought millions of African Americans to Chicago, Detroit, New York, Philadelphia, Washington, D.C., and other cities that have large African American populations today. Since the 1970s, however, there has been return migration to the South. There is net in-migration of blacks and an even greater influx of other Americans. This phenomenon is part of the fourth and now major stream, the movement from the Snowbelt states to the Sun Belt states.⁷⁰

More dramatic and more rapid than regional shifts in population is the redistribution of population within and around metropolitan areas. Within a decade, city neighborhoods can change from middle-class family homes to densely populated ghettos of non-English-speaking immigrants. Rolling farmland 30 miles from downtown can quickly sprout dense townhouse developments. Because these changes affect a community's tax base, public school enrollment, student-body composition, traffic congestion, and public services, they often spark contentious political battles.

Metropolitan areas consist of central cities, suburbs, and combinations of these parts (such as a Consolidated Metropolitan Statistical Area, or CMSA). As growth patterns and socioeconomic relationships among the components of metropolitan areas change, definitions change. After each decennial census, some metropolitan areas in the United States are redefined, usually by expanding them to include adjacent counties. In 1996, there were 273 metropolitan areas defined by the U.S. Office of Management and Budget, ranging in population size from 57,000 (Enid, Okla.) to 19.9 million (New York City and environs).

Metropolitan areas grew faster than nonmetropolitan areas for all of this country's history—at least until the 1970s. Some demographers detect a reversal of this long-term pattern and a rebirth of rural America in the 1990s. This renaissance has been ushered in by affluent retirees, telecommuting professionals, and the construction of factories in nonmetropolitan areas.⁷¹

In every metropolitan area, however, suburban areas grow more rapidly than central cities. Many central cities such as Philadelphia have been losing population for several decades.

Metropolitan areas grow outward from original central cities, gobbling up additional cities and counties in their paths. Los Angeles, for instance, has more incorporated cities within its sprawl than do some states.

More recently, transportation and communications advances, restructuring of jobs, and other changes are altering the landscape of cities. More jobs are becoming available in the suburban and "exurban" areas outside metropolitan areas. Rush-hour traffic now flows in all directions, not just into downtown areas. "Edge cities"—quasi-urban agglomerations of office parks and shopping centers—are evolving on the periphery of metropolitan areas. Edge cities usually lack the distinct character of a central city. They often do not have a mayor or even definite boundaries, but they have emerged as "hot spots" for jobs, entertainment, and residential growth.⁷²

Population distribution and redistribution affect the demographic composition of the areas involved and can generate many social and economic consequences. For example, the high rate of migration into Florida of both immigrants and internal migrants in the 1980s and 1990s has not only moved that state from seventh to fourth place in population rank but has fundamentally altered the state's age, racial, and ethnic composition. In metropolitan areas, middle- and upper-income Americans are leaving central cities and low-income suburbs for wealthier suburbs or neighboring rural counties. They leave behind groups that are disproportionately poor. This concentrates the negative social and economic consequences of poverty and further segregates the poor from the middle and upper classes.

Demographer Douglas Massey predicts these trends will be self-perpetuating. The geographic distance and concentration of poverty will foster the evolution of incompatible cultures, and it will be increasingly hard for the poor and wealthy to interact on the job, in the classroom, or in social situations.⁷³ Sociologist William Julius Wilson suggests that the African American poor in urban areas lost an important source of social and economic support when middle- and upper-class blacks moved out of central cities. This perpetuated the unemployment and unstable family lives common among blacks in low-income areas.⁷⁴