Visualizing Environmental Science

Population and Urbanization 185

© Royal GeographicalSociety/Alamy Limited

New York, USA

20.6

2025 projections

City populations

in millions

25 and over

20 to 24

15 to 19

Tokyo, Japan

36.4

Shanghai,

China

19.4

Kolkata,

India

20.6

Mexico City, Mexico

21.0

Dhaka,

Bangladesh

22.0

São Paulo, Brazil

21.4

Delhi,

India

22.5

Mumbai,

India

26.4

Karachi,

Pakistan,

19.1

Source: From Raven, Hassenzahl, Berg: Environment, 8e, copyright 2012. John Wiley and Sons, Inc. This material is reproduced with permission of John Wiley and Sons, Inc.

In contrast, the fast pace of urban growth in devel-

oping nations has outstripped the limited capacity of

many cities to provide basic services. It has overwhelmed

their economic growth (although cities still offer more

job possibilities than rural areas). Consequently, cities

in developing nations generally face more serious chal-

lenges than cities in highly developed countries. These

challenges include substandard housing (slums and

squatter settlements); poverty; exceptionally high unem-

ployment; urban violence; environmental degradation

and increasing water and air pollution; and inadequate

or nonexistent water, sewage, and waste disposal (Figure

7.25). Rapid urban growth also strains school, medical,

and transportation systems. Virtually all environmental

problems are exacerbated—and sometimes triggered—

by rapid population growth, so urbanization challenges

society to develop solutions to burgeoning environmental

issues while addressing the vast needs of urban populations.

1. Which countries are the most urbanized? the
   least urbanized? Which countries have the
   highest rates of urbanization today?


2. What are some of the problems caused by
   rapid urban growth in developing countries?


3. How does compact development affect city living?

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In 2025, 8 of the 10 largest cities will be in developing countries: Mumbai, Delhi, Dhaka, São Paulo, Mexico City, Kolkata, Shanghai, and Karachi.

The challenge of meeting a fast-growing city’s

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An open sewer runs through a shanty town in Nairobi, Kenya.

Residents use the stream as a source of drinking water. Lack of

access to safe water and basic sanitation services is a problem

for many urban residents, particularly the poor, in less developed

countries.

developed nations. Here, most of the migration to cities

occurred during the past 150 years, when an increased

need for industrial labor coincided with a decreased need

for agricultural labor. The growth of U.S. cities over such

a long period was typically slow enough to allow important

city services such as water purification, sewage treatment,

education, and adequate housing to keep pace with the

influx of people from rural areas.