CITIESBrennan (1998, pp. 75–114) have suggested that
cities’ size and rates of population growth are
inversely related to welfare. Kasarda and Crenshaw
(1991, pp. 471–474) note that megacities, which
may have serious social and economic problems,
can be driving engines for industrial production in
developing regions, and contribute disproportion-
ately to their countries’ economies (Kasarda and
Crenshaw 1991, pp. 467–501).
Berry (1978) indicates that urbanization may
be accompanied by ‘‘counter-urbanization’’ or de-
creasing city size and density. City growth some-
times occurs in cycles, which begin with rapid
growth in the urban core, followed by rapid growth
in the suburban ring, a decline in growth in both
the core and the ring, and then rapid growth in the
core (United Nations 1998). These cycles—of ur-
banization, suburbanization, counter-urbanization,
and reurbanization—appear to be associated with
concentrations of services in city centers, followed
by improvements in commuting by the labor force
and increased suburban home ownership by ur-
ban labor forces. The 1970s deurbanization (met-
ropolitan turnaround) in the United States was
followed by reurbanization in the 1980s, and the
start of another period of deurbanization in the
1990s (United Nations 1998). During the 1970s
and 1980s counter-urbanization occurred in other
more developed regions and in less developed
regions, including a slow-down of population
growth rates in some megacities in developing
regions, particularly in Latin America (United Na-
tions 1998).
Changes in the global economy and in the
aforementioned city growth cycles are associated
with new forms of urban land use in the United
States, which are laid over preexisting urban pat-
terns. Businesses, which provide the economic
base for cities, move between optimum locations
in different cities (Wilson 1997, p. 8). Globalization
has enhanced the growth of suburbs and ‘‘edge
cities’’ organized around outlying business and
high-technology centers linked by telecommunica-
tions networks to other cities (Castells, 1989; Mul-
ler 1997). Unregulated informal sectors of the
economy develop in a variety of intraurban loca-
tions. High-income native and immigrant popula-
tions, which profit from the new global economy,
sometimes cluster in protected enclaves. Low-in-
come immigrant and ethnic populations often
occupy areas inhabited by earlier cohorts of the
urban poor. Such trends may be related to a
spread of ghetto-underclass neighborhoods and to
increasingly polarized intracity neighborhood dif-
ferences of poverty and affluence (Morenoff and
Tienda 1997, pp. 59–72).Trans-border cites are new urban forms that
transcend the boundaries of nation-states and re-
flect increasingly borderless economies. They re-
sult from globalization trends, including the eco-
nomic integration of regions, reductions of trade
barriers, and the establishment of multinational
free trade zones. They link cities adjacent to a
border, and sometimes metamorphose into trans-
border systems, complete with specialized func-
tions and populations, and extensive cross-border
social and economic ties (Rubin-Kurtzman et al.
1993). Examples are Southern California (U.S.)-
Baja California (Mexico), the Singapore-Johore
(Malysia)-Riau (Indonesia) region, and the Beijing
(China)-Pyongyang (North Korea)-Seoul (South
Korea)-Tokyo (Japan) urban corridor. Trans-bor-
der cities pose questions regarding the limits of
national sovereignty, but can also integrate human
and economic resources and thus enhance inter-
national stability.Cities will continue to exhibit extremes of
affluence and poverty, but the extent and conse-
quences of these extremes are unclear. Massey
(1996, pp. 395–412) has argued that both the
affluent and the poor are concentrating in cities in
the United States; consequences may include in-
creased densities of crime, addictions, diseases,
and environmental degradation, the emergence of
oppositional subcultures, and enhanced violence.
Massey assumes these trends apply to less devel-
oped regions as well as to the United States. Farley
(1996, pp. 417–420) has advanced a counterargument
that while economic inequality is increasing in the
United States, as may be the geographic segrega-
tion of the poor, the continuing (1996) rise in
prosperity increases welfare at all income levels.
Firebaugh and Beck (1994, pp. 631–653) maintain
that economic growth, even in dependent less
developed countries, may eventually increase wel-
fare. Hout et al. (1998) state that political institu-
tions, which are partially responsible for growing
inequality, can provide appropriate remedies.As cities account for increasing shares of the
earth’s population, they will consume increasing
shares of the earth’s resources, produce increasing