1. Copyright © 2005 Pearson Education, Inc., publishing as Benjamin Cummings PowerPoint ® Lecture prepared by Jay Withgott Scott Brennan Jay Withgott 5 Human population growth

2. Copyright © 2005 Pearson Education, Inc., publishing as Benjamin Cummings This lecture will help you understand: Human population growth Demography Affluence, technology, the status of women, and the environment Population control programs Demographic transition theory Consumption and the ecological footprint HIV/AIDS and human population

3. Copyright © 2005 Pearson Education, Inc., publishing as Benjamin Cummings Central Case: China’s One-Child Policy Unfettered population growth posed challenges for China’s environment, economy, and political stability. China tried to control its growth with a system of rewards and punishments to encourage one-child families. The program decreased population growth, but meant government intrusion in private reproductive choices.

4. Copyright © 2005 Pearson Education, Inc., publishing as Benjamin Cummings “Baby Six Billion” The world’s population now exceeds 6 billion people. The UN marked this symbolically by declaring a child born in 1999 in war-torn Sarajevo as the six-billionth baby. Figure 7.1

5. Copyright © 2005 Pearson Education, Inc., publishing as Benjamin Cummings World population has risen sharply Global human population was <1 billion in 1800. Population has doubled just since 1963. We add 2.5 people every second (79 million/year). Figure 7.2

6. Copyright © 2005 Pearson Education, Inc., publishing as Benjamin Cummings Population growth rates, 1990-1995 Growth rates vary from place to place. Growth peaked at 2.1% in the 1960s; it has now declined to 1.3%. Figure 7.3

7. Copyright © 2005 Pearson Education, Inc., publishing as Benjamin Cummings Is population growth really a problem? Some say NO: People can find or manufacture additional resources to keep pace with population growth. Nations become stronger as their populations grow. Some say YES: Not all resources can be replaced. Even if they could, quality of life suffers. Nations do not become stronger as their populations grow.

8. Copyright © 2005 Pearson Education, Inc., publishing as Benjamin Cummings Modeling population and its consequences Some models show population growth leading to resource depletion, which can result in declining food production, industrial output, and population. Figure 7.4

9. Copyright © 2005 Pearson Education, Inc., publishing as Benjamin Cummings Increasing our carrying capacity Technology has allowed us to raise Earth’s carrying capacity for our species time and again. Tool-making, agriculture, and industrialization each enabled humans to sustain greater populations. Figure 7.5

10. Copyright © 2005 Pearson Education, Inc., publishing as Benjamin Cummings Demography Demography is the study of human populations. Human populations exhibit the same fundamental characteristics as do populations of all other organisms.

11. Copyright © 2005 Pearson Education, Inc., publishing as Benjamin Cummings Population size: National populations Nations vary from China’s 1.3 billion down to Pacific island nations of 100,000. Shown are the 15 most populous countries, and selected others; 2002 data. Figure 7.6

12. Copyright © 2005 Pearson Education, Inc., publishing as Benjamin Cummings Population size: Future projections Demographers project population growth trends to estimate future population sizes. Different fertility rate scenarios predict global population sizes in 2050 of 7.4 billion, 8.9 billion, or 10.6 billion. All these projections assume fertility rates below today’s; at today’s rate, the population would reach 12.8 billion. Figure 7.7

13. Copyright © 2005 Pearson Education, Inc., publishing as Benjamin Cummings Population density and distribution Figure 7.8 Humans are unevenly distributed, living at different densities from region to region.

14. Copyright © 2005 Pearson Education, Inc., publishing as Benjamin Cummings Age structure Age structure can influence population growth rates. Figure 7.9

15. Copyright © 2005 Pearson Education, Inc., publishing as Benjamin Cummings Age structure: Age pyramids Canada (left) has a much slower growing population than does Madagascar (right). Figure 7.10

16. Copyright © 2005 Pearson Education, Inc., publishing as Benjamin Cummings Age structure: “Graying populations” Demographers project that China’s population will become older over the next two decades. Figure 7.11a,b

17. Copyright © 2005 Pearson Education, Inc., publishing as Benjamin Cummings Age structure: “Graying populations” China’s aging population will mean fewer working-age citizens to finance social services for retirees. Figure 7.11c

18. Copyright © 2005 Pearson Education, Inc., publishing as Benjamin Cummings Age structure: “Baby booms” The United States’ “baby boom” is evident in age bracket 40–50. U.S. age structure will change as baby boomers grow older. Figure 7.12

19. Copyright © 2005 Pearson Education, Inc., publishing as Benjamin Cummings Sex ratios A population’s sex ratio can affect its growth rate. Figure 7.13

20. Copyright © 2005 Pearson Education, Inc., publishing as Benjamin Cummings Factors affecting population growth rates Population growth depends on rates of birth, death, immigration, and emigration. (birth rate + immigration rate) – (death rate + emigration rate) = population growth rate

21. Copyright © 2005 Pearson Education, Inc., publishing as Benjamin Cummings Migration can have environmental effects Immigration and emigration play large roles today. Refugees from the 1994 Rwandan genocide endured great hardship, and deforested large areas near refugee camps. Figure 7.14

22. Copyright © 2005 Pearson Education, Inc., publishing as Benjamin Cummings Natural rate of population change Change due to birth and death rates alone, excluding migration Is often expressed in % per year

23. Copyright © 2005 Pearson Education, Inc., publishing as Benjamin Cummings China’s natural rate of change has fallen China’s rate has fallen with fertility rates. It now takes the population 4 times as long to double as it did 25 years ago.

24. Copyright © 2005 Pearson Education, Inc., publishing as Benjamin Cummings Global growth rates have fallen The annual growth rate of the world population has declined since the 1960s. (But the population size is still rising!) Figure 7.15

25. Copyright © 2005 Pearson Education, Inc., publishing as Benjamin Cummings Fertility rates affect population growth rates Total fertility rate (TFR) = average number of children born per woman during her lifetime Replacement fertility = the TFR that keeps population size stable For humans, replacement fertility is about 2.1.

26. Copyright © 2005 Pearson Education, Inc., publishing as Benjamin Cummings Total fertility rates by region African nations have the highest TFRs. European nations have the lowest TFRs.

27. Copyright © 2005 Pearson Education, Inc., publishing as Benjamin Cummings Demographic transition theory Demographic transition = model of economic and cultural change to explain declining death rates, declining birth rates, and rising life expectancies in Western nations as they became industrialized Proposed by F. Notestein in the 1940s-1950s

28. Copyright © 2005 Pearson Education, Inc., publishing as Benjamin Cummings Demographic transition: Stages Figure 7.18

29. Copyright © 2005 Pearson Education, Inc., publishing as Benjamin Cummings Demographic transition: Stages The demographic transition consists of several stages: Pre-industrial stage: high death rates and high birth rates Transitional stage: death rates fall due to rising food production and better medical care. Birth rates remain high, so population surges. Industrial stage: birth rates fall, as women are employed and as children become less economically useful in an urban setting. Population growth rate declines. Post-industrial stage: birth and death rates remain low and stable; society enjoys fruits of industrialization without threat of runaway population growth.

30. Copyright © 2005 Pearson Education, Inc., publishing as Benjamin Cummings Female education and TFR Female literacy and school enrollment are correlated with total fertility rate: More-educated women have fewer children. Figure 7.16

31. Copyright © 2005 Pearson Education, Inc., publishing as Benjamin Cummings Family planning and TFR Family planning, health care, and reproductive education can lower TFRs. A counselor advises African women on health care and reproductive rights. Figure 7.17b

32. Copyright © 2005 Pearson Education, Inc., publishing as Benjamin Cummings Family planning and TFR Nations that invested in family planning (green) reduced TFRs more than similar nations that did not (red). Figure 7.17a

33. Copyright © 2005 Pearson Education, Inc., publishing as Benjamin Cummings TFR decline in Bangladesh Bangladesh reduced TFR from 7.1 to 4.6 in 25 yr, and is at 3.3 today. Family planning, education, and outreach were responsible. From The Science behind the Stories

34. Copyright © 2005 Pearson Education, Inc., publishing as Benjamin Cummings HIV/AIDS and human population AIDS cases are increasing rapidly worldwide. Figure 7.26

35. Copyright © 2005 Pearson Education, Inc., publishing as Benjamin Cummings HIV/AIDS and human population Infects 1 in 5 people in southern African nations Infects 5 million new people each year Kills babies born to infected mothers Has orphaned 14 million children Has cut 15 years off life expectancies in parts of southern Africa Figure 7.27

36. Copyright © 2005 Pearson Education, Inc., publishing as Benjamin Cummings Poorer countries will experience most future population growth 98% of the next billion people born will live in developing nations. Figure 7.20

37. Copyright © 2005 Pearson Education, Inc., publishing as Benjamin Cummings Population and the environment Population growth can lead to environmental degradation. Overpopulation in Africa’s Sahel region has led to overgrazing of semi-arid lands. Figure 7.21

38. Copyright © 2005 Pearson Education, Inc., publishing as Benjamin Cummings Affluence and the environment Poverty can lead to environmental degradation… BUT wealth and resource consumption can produce even more severe and far-reaching environmental impacts.

39. Copyright © 2005 Pearson Education, Inc., publishing as Benjamin Cummings The ecological footprint The cumulative amount of Earth’s surface area required to provide the raw materials a person or a population consumes and to dispose of or recycle the waste that is produced

40. Copyright © 2005 Pearson Education, Inc., publishing as Benjamin Cummings Ecological footprints Residents of some countries consume more resources—and thus use more land— than residents of others. Shown are ecological footprints of an average citizen from various nations. Figure 7.23

41. Copyright © 2005 Pearson Education, Inc., publishing as Benjamin Cummings The wealth gap Residents of developed nations have larger houses, more possessions, and more money than residents of developing nations. The richest 20% of the world’s people consumes 86% of its resources, and has >80 times the income of the poorest 20%. Figure 7.25

42. Copyright © 2005 Pearson Education, Inc., publishing as Benjamin Cummings Demographic fatigue and demographic transition Many governments of developing countries are experiencing “demographic fatigue,” unable to meet the social, economic, and environmental challenges imposed by rapid population growth. This raises the question: Will today’s developing countries successfully pass through the demographic transition?

43. Copyright © 2005 Pearson Education, Inc., publishing as Benjamin Cummings The “IPAT” model Shows how Population, Affluence, and Technology interact to create Impact on our environment. I = P  A  T Further factors can be added to the original equation of Holdren and Ehrlich to make it more comprehensive.

44. Copyright © 2005 Pearson Education, Inc., publishing as Benjamin Cummings Conclusions: Challenges Human population is rising by 79 million people annually. Many more people are born into poverty than into wealth. Rich and poor nations are divided by a “wealth gap.” HIV/AIDS is taking a heavy toll. Population growth has severe environmental effects.

45. Copyright © 2005 Pearson Education, Inc., publishing as Benjamin Cummings Conclusions: Solutions Expanding women’s rights is crucial to encourage the demographic transition. Health and reproductive education and counseling can reduce fertility rates. Education, medicine, and policies can lessen the toll of HIV/AIDS. New “green” technologies can help reduce population growth’s environmental impacts.

46. Copyright © 2005 Pearson Education, Inc., publishing as Benjamin Cummings Viewpoints: Population control? Timothy Cline Douglas Sylva “Access to reproductive health care, including family planning, is a basic human right.” “Governments do not have an interest in further reducing fertility. Nor should they have the authority to do so.” From Viewpoints

47. Copyright © 2005 Pearson Education, Inc., publishing as Benjamin Cummings QUESTION: Review Using the I = P  A  T equation, what would happen if the population doubled? a.Affluence and technology would decline. b.The environment would become more sensitive. c.The environmental impact would double. d.Nothing, because Earth can compensate.

48. Copyright © 2005 Pearson Education, Inc., publishing as Benjamin Cummings QUESTION: Review What has allowed us to increase Earth’s carrying capacity for our species? a.Agriculture b.Industrialization c.Tool-making d.All of the above

49. Copyright © 2005 Pearson Education, Inc., publishing as Benjamin Cummings QUESTION: Review Which statement is FALSE? a.The global population growth rate is decreasing. b.The global population is increasing. c.At a TFR of 2.4, a human population grows. d.Populations with age distributions skewed toward young people grow more slowly.

50. Copyright © 2005 Pearson Education, Inc., publishing as Benjamin Cummings QUESTION: Review Women who are more educated tend to… ? a.Have higher TFRs. b.Live in developing nations. c.Have fewer children. d.Contract HIV/AIDS.

51. Copyright © 2005 Pearson Education, Inc., publishing as Benjamin Cummings QUESTION: Weighing the Issues Should the United States fund family planning efforts in other nations? a.Yes, without reservation b.Yes, in nations whose programs it approves c.Only if it can influence the nations’ policies d.Never under any circumstances

52. Copyright © 2005 Pearson Education, Inc., publishing as Benjamin Cummings QUESTION: Interpreting Graphs and Data What happens during the “transitional stage” of the demographic transition? a.Birth rates rise; death rates drop; population increases b.Birth rates drop; death rates drop; population decreases c.Death rates drop; birth rates are stable; population increases Figure 7.18

53. Copyright © 2005 Pearson Education, Inc., publishing as Benjamin Cummings QUESTION: Viewpoints Do you believe that national governments should implement policies, subsidies, or other programs to reduce birth rates? a.No, not at all b.Yes, but only positive incentives for fewer children c.Yes—penalties for too many children d.Yes, both incentives and penalties