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cgw4ua_unit_1_lesson_02.pdf

2 CGW4U-A

World Population: Change and Challenge

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Canadian and World Issues CGW4U-A Lesson 2, page 1

Introduction The world’s population is growing at a staggering rate, but the rate is much higher in some regions than in others. For example, the estimated annual population growth in Africa from 2000 to 2050 is 2.4 percent; for North America, the figure is 0.6 percent. In Europe, the population is actually declining at an annual rate of 0.3 percent. What are the implications of these changes in the world’s population, and what challenges face the world as a result? In this lesson, you will have an opportunity to explore these problems and to examine the potential consequences for different regions. You will apply statistical analysis to draw conclusions about future population growth or decline.

What You Will Learn

After completing this lesson, you will be able to

• explain why population growth or decline occurs

• predict how the world population will change and how these changes will affect the environment and people’s ways of life

• use different methods of statistical analysis to examine and to explain global population trends and changes

• use appropriate maps and charts to illustrate regional or global population patterns and relationships

Lesson 2, page 2 Canadian and World Issues CGW4U-A

Copyright © 2007 The Ontario Educational Communications Authority. All rights reserved. www.ilc.org

Glossary of Key Terms

The following terms are in bold in the lesson.

age quake: aging of a country’s population caused by declining fertility rates.

demographer: expert who studies population statistics.

dependency load: the amount of a country’s population under 16 and over 65. Gives an estimate of the tax burden on the working population to provide necessary social services.

developed countries (DCs):

countries with high standards of living, diverse and prosperous economies, and low fertility rates.

exponential growth: rapid rate of growth in which numbers keep doubling.

Food and Agriculture Organization (FAO):

UN agency dedicated to improving the world’s food supply.

less developed countries (LDCs):

countries with low standards of living, struggling or developing economies, and higher fertility rates.

life expectancy: average number of years lived by people in a country.

Neo-Malthusians: modern demographers who agree with the Malthusian theory that famine, disease, and war will increase when human population growth surpasses the Earth’s available resources.

replacement level: total fertility rate required for a country to maintain its population. The value is 2.1.

Rule of 70: method used to estimate the number of years it will take for a country’s population to double. Divide the number 70 by the percentage change from one year to the next.

total fertility rate: number of children a woman will have in her lifetime.

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Canadian and World Issues CGW4U-A Lesson 2, page 3

World Population: The Numbers Within the next hour, there will be 8480 more people on this planet. That means an additional 67 840 people over an eight- hour shift of work or a good night’s sleep (see Figure 2.1).

Time unit Births Deaths Natural increase

Year 130 860 569 56 579 396 74 281 173

Month 10 905 047 4 714 950 6 190 098

Day 358 522 155 012 203 510

Hour 14 938 6 459 8 480

Minute 249 108 141

Second 4.1 1.8 2.4

Note: Figures may not add to totals due to rounding

Figure 2.1. World vital events per time unit, 2006.

Source: U.S. Census Bureau, International Data Base.

Every second of 2006, there will be 4.1 births in the world. (Try saying ”four-point-one” every second for 10 seconds. Although you may stop counting, this growth never stops.) There are 1.8 deaths every second as well. So the population of the world is growing at the rate of 2.4 per second. This growth is known as natural increase. In 2006 alone, the population of almost two Canadas will be added to the world. Since the rate of natural increase itself increases as the total gets bigger, more and more people are added to the world every year, and available space and resources cannot accommodate this growth. The amount of water on this planet today is finite. If there are millions more thirsts to quench each year, there could be serious problems in the future. The capacity to grow more foods may increase through developments in agricultural science, but the additional food lands we need will not have the best soils, as these lands are already overused. Yet the people still come and the population still grows.

Lesson 2, page 4 Canadian and World Issues CGW4U-A

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The chart in Figure 2.2 shows the world’s total population for the thousand years from 1000 to 2000, and the chart in Figure 2.3 shows the UN prediction of world population figures for the years 2005 to 2050. Note that there are two different predictions on world population growth. The “High Growth” set of numbers assumes that high population growth will continue. The “Low Growth” set of numbers assumes lower growth as people throughout the world have smaller families and there are more diseases such as AIDS.

Year Population (billions) Year Population (billions)

1000 0.30 1970 3.70

1250 0.31 1980 4.44

1500 0.50 1990 5.27

1750 0.79 2000 6.06

1800 0.98

1850 1.26

1900 1.65

1950 2.52

1960 3.02

Figure 2.2. World population increase between 1000−2000.

Source: United Nations Population Division, Department of Economic & Social Affairs, “World Population to 2300,” www.un.org/esa/population/publications/longrange2/WorldPop2300final.pdf

Year High growth (in billions) Low growth (in billions)

2005 6.5 6.4

2010 7.0 6.7

2015 7.4 6.9

2020 7.9 7.2

2025 8.4 7.3

2030 8.8 7.5

2035 9.3 7.5

2040 9.7 7.5

2045 10.2 7.5

2050 10.6 7.4

Figure 2.3. United Nations high- and low-growth predictions.

Source: United Nations Population Division, Department of Economic & Social Affairs, “World Population to 2300,” www.un.org/esa/population/publications/longrange2/WorldPop2300final.pdf

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Canadian and World Issues CGW4U-A Lesson 2, page 5

Support Question

(do not send in for evaluation)

9. Using the data in Figures 2.2 and 2.3, make a line graph that shows the world population growth from 1000 to 2050. The following sample grid plots the data for the first four dates.

S A M P

L E

1

2

1000 1250 1500 1750 2000

Year

P op

ul at

io n

(b ill

io ns

)

• • •

When you create your graph, make sure that the horizontal scale, which you will use to represent time, is broken into appropriate time sections. For the portion from 2000 to 2050, you need to draw two lines to show the predictions for high and low population growth. What can you conclude about your finished graph? Write one or two paragraphs describing the information on the graph and its meaning.

There are Suggested Answers to Support Questions at the end of this unit.

Rate of Growth

In your written description of the graph in Support Question 9, you probably noted many years of gradual slow growth followed by a rapid rise in population growth. It is quite dramatic!

Lesson 2, page 6 Canadian and World Issues CGW4U-A

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This pattern is called exponential growth. A number grows exponentially when its increase is always proportional to its current amount. For example, consider a number that doubles in size every five years. Growth does not appear rapid when the base number is small (2 becomes 4, 4 becomes 8, 8 becomes 16, and so on), but when the base number is large, a doubling can be quite different (256 becomes 512, 512 becomes 1024, 1024 becomes 2048, and so on). There has been exponential population growth in recent history, and the numbers are now very large. Demographers (researchers who study population numbers) use a special rule to calculate when a country’s population will double: the Rule of 70.

The Rule of 70 can be used to estimate the number of years it will take for a country’s population to double. For this calculation, divide the number 70 by the relative change (percentage change—growth or decline—from one year to another).

For example, a country’s population grows from 40 million to 42 million in one year. The actual change is 2 million. To calculate this as a relative number, divide 2 million by 40 million (starting population) and multiply by 100 (to get a percentage).

In this case, there is 5 percent relative growth. To calculate when this country’s population will double from 40 to 80 million, apply the Rule of 70: divide 70 by the relative change of 5 percent, which gives 14 years.

Now try your own calculation: according to the U.S. Census Bureau, in 2005 Mali had a population of 12 291 529 and an annual relative change of 2.75 percent. Its population will double in 70/2.75 or 25 years. Mali will therefore have approximately 24.5 million people by the year 2005 + 25 = 2030.

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Canadian and World Issues CGW4U-A Lesson 2, page 7

Support Question

(do not send in for evaluation)

10. a) Using the Rule of 70, complete the population growth calculations in the following table.

Country Relative Change (% annual growth)

2005 Population

Doubling Time (years)

Year When Doubled

New Population

Uganda 3.3% 27 269 482

Peru 1.4% 27 925 628

Chad 2.9% 9 826 419

Canada 0.9% 32 805 041

Source: U.S. Census Bureau, International Data Base.

b) Which of the four countries represented in the chart should be most concerned about its population growth? Explain why.

Impacts of Rapid Population Growth

As you have learned, a country’s population can double in a relatively short time. Some of the poorest countries in the world have growth rates in excess of 2.5 percent, which means their population doubles in twenty-eight years or less. According to the UN, Somalia’s population of 8.4 million in 2005 will double to 16.8 million in only 21 years, double again to 33.6 million by 2047, and to 67.2 million by 2068. This will be a terrible burden on a developing east African country where the average life expectancy is 48 years and annual average per capita income is $600.

The Food and Agriculture Organization (FAO), a UN agency dedicated to improving the world’s food supply, estimates that there are 1 to 2 billion malnourished individuals in the world today. With the collaboration of the International Institute for Applied Systems Analysis, the FAO estimates that there is currently 1.6 billion hectares of actual and potential cropland

Lesson 2, page 8 Canadian and World Issues CGW4U-A

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worldwide. To meet growing populations, this has to increase to 4 billion hectares by 2050. As demand for food grows, so does the demand for fresh water (80 percent of water consumption is accounted for by agriculture). China’s growing demand for grain will possibly threaten the entire exported amount of grain in the world today.

The populations of global emerging economies, such as China and India, will increase by an estimated 625 million by 2050. There will be huge growth in demand for the world’s resources such as energy, lumber, and metals, as well as an increased threat to the world’s natural environment as cities sprawl into surrounding areas. There may be an increased number of conflicts as groups compete for space and control over scarce resources. The next war in the Middle East may well be fought over water supplies and not political tensions. One major stress is the fact that the traditionally poorer parts of the world are improving their economies, raising their levels of consumerism (desire and need to purchase goods and services). This will put great pressures on the world’s ability to provide the resources it needs to satisfy this demand.

A Malthusian Future?

If the world population continues to grow exponentially, as some population experts predict, with four billion people being added by 2050, there may be some unpleasant consequences. This has been suggested for quite some time—more than 200 years, in fact. In 1798, Thomas Robert Malthus (1766−1843) wrote in “Essay on the Principle of Population” that food supply would grow gradually, whereas population would grow rapidly. He stated that population growth outstrips food supply: while the amount of food supply grows arithmetically, or by the same amount for each unit of time (2, 4, 6, 8, 10, 12 ...), population increases exponentially (1, 2, 4, 8, 16, 32 ...). He also believed that people do not have the moral restraint to control their numbers, and that the population growth would be controlled through famine, disease, and even war.

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Canadian and World Issues CGW4U-A Lesson 2, page 9

Malthus’s prediction that the world’s population would double every 25 years did not come to pass. If it had, we would now be struggling with a world population of 243 billion! Nevertheless, there are demographers today, called “neo-Malthusians,” who believe that the world cannot sustain the large estimated growth in population. They also worry about such things as food and water supply, and city sanitation and the spread of disease. Joel E. Cohen is a demographer who writes about future trends in population. He could be described as a neo-Malthusian because he does not feel that humans can sustain continual population growth. Cohen also believes in the power of human beings to use their intelligence to make choices. Here is a piece about Cohen’s article “Human Population: The Next Half-Century.”

By the Year 2050, Human Population Could Add 2.6 Billion People

It took from the beginning of time until 1950 to put the first 2.5 billion people on the planet. Yet in the next half-century, an increase that exceeds the total population of the world in 1950 will occur.

So writes Joel E. Cohen, Ph.D., Dr.P.H., professor and head of the Laboratory of Populations at The Rockefeller University and Columbia University, in a Viewpoint article in the November 14 issue of the journal Science.

In “Human Population: The Next Half-Century,” Cohen examines the history of human population and how it might change by the year 2050.

By then, the earth’s present population of 6.3 billion is estimated to grow by 2.6 billion. “There are some things we can reasonably know and other things we cannot know,” Cohen says about population projections. “By examining population size and distribution, it is possible to get a feeling for possible challenges to our future well-being. It is possible to get a sense of the larger picture.”

What can be reasonably predicted? The world’s population will be growing at a slower rate than it is

Lesson 2, page 10 Canadian and World Issues CGW4U-A

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today, especially in the richer, developed countries, but it will be larger by 2 to 4 billion people. It will also be more urban, especially in the underdeveloped countries. And it will be more elderly. However, exactly how international migration and family structures will change demographers cannot say.

“I also do not know whether we will inflict a doomsday on ourselves by warfare, disease or catastrophe. Our future depends on choice—on the choices we have made in the past and those we will make in the future,” adds Cohen. “We cannot continue the exceptional growth of this last half century without experiencing consequences.”

The demographic projections that Cohen cites assume that fertility rates will continue to decline and that more effective preventions and treatments against HIV and AIDS will be implemented and major catastrophes such as biological warfare, severe climate change, or thermonuclear holocaust will not be inflicted on the human population and the planet. These assumptions underlie the United Nations Population Division’s urbanization forecasts and its online database, World Population Prospects: The 2002 Revision. In the Science article, Cohen reports such statistical information as the following:

History of human population: It took from the beginning of time until about 1927 to put the first 2 billion people on the planet; less than 50 years to add the next 2 billion people (by 1974); and just 25 years to add the next 2 billion (by 1999). In the most recent 40 years, the population doubled.

Birth rates: The global total fertility rate fell from five children per woman per lifetime in 1950 to 2.7 children in 2000, a result of worldwide efforts to make contraception and reproductive health services available, as well as other cultural changes. Encouraging as this is, if fertility remains at present levels instead of continuing to decline, the population would grow to 12.8 billion by 2050 instead of the projected 8.9 billion.

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Canadian and World Issues CGW4U-A Lesson 2, page 11

Urbanization: In 1800, roughly 2 percent of people lived in cities; in 1900, 12 percent; in 2000, more than 47 percent. In 1900, not one metropolitan region had 10 million people or more. By 1950, one region did—New York. In 2000, 19 urban regions had 10 million people or more. Of those 19, only four (Tokyo, Osaka, New York, and Los Angeles) were in industrialized countries.

Poor, underdeveloped regions: Despite higher death rates, the population of poor countries grows six times faster than that of rich countries.

Population density: The world’s average population density is expected to rise from 45 people per square kilometer in the year 2000 to 66 people per square kilometer by 2050. Assuming 10 percent of land is arable, population densities per unit of arable land will be roughly 10 times higher, posing unprecedented problems of land use and preservation for the developing world.

Aging population: The 20th century will probably be the last when younger people outnumbered older ones. By 2050, there will be 2.5 people aged 60 years or older for every child 4 years old or younger, a shift that has serious implications for health care spending for the young and old.

Although it is not possible to predict how global demographics will affect families or international migration, Cohen points out that three factors set the stage for major changes in families: fertility falling to very low levels; increasing longevity; and changing mores of marriage, cohabitation and divorce.

In a population with one child per family, no children have siblings, Cohen explains. In the next generation, the children of those children have no cousins, aunts, or uncles.

If people are between ages 20 and 30 on the average when they have children and live to 80 years of age, they will have decades of life after their children have reached adulthood, and their children

Lesson 2, page 12 Canadian and World Issues CGW4U-A

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will have decades of life with elderly parents, Cohen also points out. Cohen’s article kicks off a four-week long series titled “The State of the Planet,” which examines key issues of our planet’s well-being. Cohen was asked to initiate the series because “population is people and people matter.”

Source: The Rockefeller University, The Earth Institute, “By the Year 2050, Human Population Could Add 2.6 Billion People,” www.earthinstitute.columbia.edu/news/2003/story11-19-03.html Posted November 19, 2003.

Support Question

(do not send in for evaluation)

11. Using the information you have read about the world’s population changes, briefly describe, in one or two sentences for each, five significant impacts that may occur as a consequence of continued world population growth.

Regional Differences

At the start of this lesson, you were given data showing that the world’s population grows by more than 200 000 (a significant- sized city) each day. The UN projects that by 2050 the world’s population will grow by between 1.5 and 4 billion. You have also examined the consequences of there being too many people in the world. Will everyone suffer these consequences equally? Population growth is not equal in all regions of the world: in some, growth is very fast; in others, it is much slower. There are even regions where there is no population growth, and the concern is that these populations are actually declining in size. Figure 2.4 shows population totals for the world’s six continental regions from 1900 to a projection for 2050.

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Canadian and World Issues CGW4U-A Lesson 2, page 13

Region 1900 1950 2000 2050

Africa 133 221 800 1766

Asia 947 1402 3684 5268

Europe 408 547 727 628

Latin America & Caribbean 74 167 517 809

North America 82 172 306 392

Oceania 6 13 31 46

Total world population 1650 2522 6065 8909

Figure 2.4. Population of world regions (in millions) 1900-2050.

Source: CIA World Factbook, www.cia.gov/cia/publications/factbook/rankorder/2119rank.html and United Nations Population Division, Department of Economic & Social Affairs, “World Population to 2300,” www.un.org/esa/population/ publications/longrange2/WorldPop2300final.pdf

Support Questions

(do not send in for evaluation)

Do a statistical analysis of the regional differences listed in Figure 2.4.

12. Which region has been the most populated in each of the years listed in Figure 2.4?

13. Which region shows the largest increase in actual population numbers between 1950 and 2050?

14. Calculate the percentage of people living in each region in the year 1950 and 2050.

(In order to do this for 1950, divide each regional population by the world’s total for 1950 and multiply by 100. For example, in 1950, North America contained 172 2522

× 100 = 6.82%.)

15. Which region is projected to show the largest increase in the percentage of the world’s population between 1950 and 2050?

16. Which region shows the greatest decline in percentage of the world’s population between 1950 and 2050?

Lesson 2, page 14 Canadian and World Issues CGW4U-A

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17. In which region did the population grow fastest between 1950 and 2000? To answer this, calculate each region’s percentage of change in growth between 1950 and 2000. For example, the population in Europe grew by 727 – 547 = 180 million between 1950 and 2000. Divide this growth in population by the population in 1950 and multiply by 100.

This is a growth of 180 547

× 100 = 32%.

18. Refer to Figure 2.5 showing the growth of countries’ populations between 2005 and 2050.

Country (2050 Rank)

Population (2005) (millions)

Proj. Population (2050)

India 1080 1531

China 1306 1395

United States 295 408

Pakistan 162 348

Indonesia 241 293

Nigeria 128 258

Bangladesh 144 254

Brazil 186 233

Ethiopia 73 170

Democratic Republic of the Congo (DROC)

60 151

Figure 2.5. Populations over 150 million 2005–2050.

Source: CIA World Factbook, www.cia.gov/cia/publications/factbook/rankorder/2119rank.html and United Nations Population Division, Department of Economic & Social Affairs, “World Population to 2300,” www.un.org/esa/population/ publications/longrange2/WorldPop2300final.pdf

a) Calculate the percentage growth for each of the countries shown between 2005 and 2050. (This is calculated in the same way as Support Question 17.)

b) Why should the government of India be concerned about its population growth?

19. Now for your conclusions. Consider the data you have calculated and the information you have read. What three significant conclusions can you make about the regional change in world’s population between 1900 and 2050?

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Canadian and World Issues CGW4U-A Lesson 2, page 15

Slow Growth and Decline

Rapid population growth, as you have learned, is worrying for the world as a whole, but for many countries, most notably in Europe, predictions indicate that their populations will continue to decline. You will look at the consequences of this later and learn why this is not good.

To understand the reason for different levels of growth and decline, you need to understand the concept of total fertility rate. Total fertility rate describes the number of children a woman will have in her lifetime. For a country to maintain its population, each couple needs to have 2.1 children. This is called the replacement level. You may think that this should be 2.0, but the added 0.1 takes into account the number of children who die before they reach reproductive age.

In 2005, the total fertility rate for the world was 2.6 per female. This number has dropped from 4.9 in 1975, but it is still sufficient for the world’s population to increase in size. Countries that include nearly half the world’s population, however, have fertility rates at or below 2.1. These countries are in what are described as the developed countries (DCs). In the less developed countries (LDCs) of the world, the average fertility rate is 2.5. The three countries with the highest fertility rates in 2005 were Niger at 7.55, Mali at 7.47, and Somalia at 6.84. This portion of the world’s population will be responsible for about 70 percent of the future total population increase, or more than 3 billion people.

If the world fertility rates were to remain at around 2.6, the world’s population would grow to more than 12 billion by 2300. The United Nations, however, predicts lower fertility rates into the future. Even a small change in the fertility rate can have a significant effect. India, with a population of more than 1 billion, and a fertility rate of 2.5, is destined soon to surpass China as the world’s most populous country. If India, which is developing its economy quite rapidly, manages to reduce the fertility rate to 2.1, its population will be the same in 100 years as it is now. On the other hand, if India continues with a fertility rate of 2.5, it will add 2 billion people in that time. In sharp contrast with

Lesson 2, page 16 Canadian and World Issues CGW4U-A

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this possibility, have a look at the table produced by the United Nations in Figure 2.6 showing projected declining populations from 2000 to 2050.

Rank Country Rate of decline in population (% per year)

1 Estonia 1.46

2 Latvia 1.16

3 Ukraine 0.90

4 Bulgaria 0.86

5 Georgia 0.83

6 Guyana 0.81

7 Armenia 0.73

8 Russia 0.72

9 Lithuania/Yugoslavia 0.65

10 Hungary 0.55

Figure 2.6. Declining populations 2000–2050 (projected).

Source: United Nations Population Division, Department of Economic & Social Affairs, “World Population to 2300,” www.un.org/esa/population/publications/longrange2/WorldPop2300final.pdf

World Fertility Rates

The map in Figure 2.7 shows the fertility rates in countries around the world.

Figure 2.7. World fertility rates.

Source: UN World Population Data Sheet.

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Canadian and World Issues CGW4U-A Lesson 2, page 17

Factors Affecting Fertility Rates

Some causes of higher fertility rates:

• the need for children in a workforce, especially true for economies based on agriculture or that have extreme poverty

• low levels of education and literacy, especially for girls who neither get a higher education nor enter the workforce

• cultures that allow girls to marry at a young age and hence start families at an early age

• high death rates, which increase the pressure to have larger families

• high rates of infant mortality

• where there are few social services, the need for children to provide security for adults in their senior years

• patrilineal social organization …