Earth's Human Geography World Geography Unit 3 Earth's Human Geography

What Is Population Distribution? The world’s population, or total number of people, is spread unevenly over the Earth’s surface. Population distribution describes the way the population is spread out. Demographers study the populations of the world to figure out why population is distributed the way it is. They examine such things as rates of birth, death, and marriage, and why people choose to live in certain areas.

Why Is Population Distribution Uneven? What affects where people will want to live? Desirable Factors Areas along bodies of water form natural travel routes and provide fresh water for drinking and farming. Plains and valleys with flat, fertile soil are good for growing food. Flat coastal areas are good for trading by ship. Areas with moderate climates and adequate rainfall Places rich in natural resources to build houses and make products Undesirable Factors Areas with rugged mountains, hot deserts, and dry land with little vegetation or water.

Continents: Populous and Not Populous About 81 percent of the Earth’s people live in Asia, Europe, and North America. Yet, these continents account for only 53 percent of the world’s land. Why? These continents have fertile soil, plains, valleys, fresh water, rich natural resources, and good climates.

Continents: Populous and Not Populous Australia’s environment is mostly desert or dry grassland, with few rivers and little rainfall. Africa is home to two of the world’s largest deserts, broad bands of land that get little rain, and a vast rain forest along the Equator. South America is also limited by landforms and climates, where many regions have soaring mountains, vast dry plains, and thick rain forests.

What Is Population Density? The average number of people who live in a square mile is called population density. In a country or city with a high population density, people are crowded together. Japan has one of the highest population densities in the world: Almost all of its people live on only 16 percent of the land. In a country or city with a low population density, people are more spread apart. Canada is bigger than the United States, but has a much smaller population.

Studying Population Density How do demographers measure population density? Divide the number of people living in a place by the number of square miles of that place. Remember, though, that the population density of an area is an average, and that people are not spread evenly over the land. Population density will usually be the highest on level areas near bodies of water. Some people, however, do live in harsh areas and over many generations have adapted ways of life to suit these environments.

Population Growth Is Worldwide By comparing the birthrate to the death rate, demographers can figure out population growth. During different historical periods, populations grew at different rates: For centuries, the world population grew slowly—food supplies were scarce and many thousands died of diseases. As a result, although the birthrate was high, so was the death rate. The life expectancy was short. A hundred years ago in the United States, people usually lived less than 50 years. World population has grown rapidly and has increased greatly in modern times. WHY?

Reasons For Population Growth Today Today, the birthrate has increased dramatically and the death rate has slowed. The population in some countries has grown very fast. People live longer than ever. In the United States today, people usually live more than 70 years. This is the result of two scientific developments: New farming methods have greatly increased the world’s food supply (called the Green Revolution). Advancements in medicine and health have resulted in people living longer lives.

The Challenges Of Population Growth The Earth’s resources must now be shared by six times as many people than in earlier times. Many countries face very serious problems, such as shortages of fresh water and energy. The rapidly growing world population poses many challenges: Higher populations make it harder to find jobs. More schools are needed for the growing number of children. Decent housing is scarce and expensive. Public services like transportation seem inadequate. Forests are disappearing because people use the wood from trees for building and for fuel. As a result, the supply of clean air decreases and soil can be washed away.

World Population Growth, A.D. 1200–2000

Migration: The Movement Of People When people move from one place to another, this is called migration. Immigrants are people who leave one country and move to another. Why do people move? Demographers use the “push-pull” theory to explain immigration. People migrate because certain things “push” them to leave. The reasons may be economic (maybe people cannot buy land or find work). Sometimes changes in government force people to leave. The hope for better living conditions “pulls” people to a country. People might be pulled by many things, such as better economic opportunities or a more desirable climate.

Irish and Vietnamese Immigrants in the United States The push-pull theory can explain the great Irish immigration in the 1840s and 1850s and Vietnamese immigration in the 1970s. Vietnamese Irish In 1975, North Vietnam finally defeated South Vietnam in a long war. In the 1840s, disease destroyed Ireland’s main crop—potatoes. Event Many South Vietnamese did not want to live under the communist government now imposed upon them. People went hungry and starved. Also, England ruled Ireland very harshly, leaving the Irish few opportunities. Push Factors The United States, their ally, welcomed them. Job opportunities in the United States Pull Factors

Other Kinds of Immigration Sometimes, people are forced to migrate. Colonization Australia was colonized by the English. The English sent convicts to serve their sentences in Australia. War When war broke out among three ethnic groups in Yugoslavia in the mid-1990s, many refugees fled to escape being killed. Helping families Young men from Morocco and Turkey often go to Europe to find work. For a few years, they work hard and save their money. Then they return home.

The World Becomes More Urban Migration also occurs within a country. One of the biggest challenges to today’s nations is urbanization—the movement of people to cities from rural areas and the growth of cities. In recent years, the population of major cities has grown tremendously. Example: Recently, in the United States, the population has shifted from the northeastern states to the southern and southwestern states. Why? People may be searching for better job opportunities or better climates. The growth of urban areas in southern states has put a great stress on services.

Growing Cities, Growing Challenges Examples of Growing Cities Jakarta, the capital of Indonesia, and São Paulo, Brazil, are examples of rapidly growing cities. Jakarta’s population more than doubled between 1978 and 2000. São Paulo is now the largest city in South America and is rapidly developing.

Growing Cities, Growing Challenges So, what’s the problem? The cities cannot keep up: They cannot provide housing, jobs, schools, hospitals, and other services that people need. Life can be difficult: Overcrowding in schools and on streets, and heavy pollution, among other things, can make life uncomfortable. So, why do people move? Most are seeking a better life for their families. They are looking for jobs, decent houses, and good schools. Above all, they want more opportunities for their children.

World Urban and Rural Populations 1800–2000