1. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Chapter 4 Lecture Outline

2. Why are we concerned about human population growth? Will the world’s population double again as it did between 1965 and 2000? What is the relationship between population growth and environmental impact? Why has the human population grown so rapidly since 1800? How is human population growth changing in different parts of the world? How does population growth change as a society develops? What factors slow down or speed up human population growth?

4. Every second, on average, four or five children are born, somewhere on the earth. In that same second, two other people die. This difference between births and deaths means a net gain of roughly 2.3 more humans per second in the world’s population. This means we are adding roughly 75 million more people per year.

5. mid-2008world population 6.7 billion 1.15 % per year The U.S. Census Bureau estimates the mid-2008 world population to be about 6.7 billion people and growing at 1.15 % per year. Humans are now one of the most numerous vertebrate species on the earth. We also are more widely distributed and manifestly have a greater global environmental impact than any other species. For the families to whom these children are born, each birth may be a joyous and long-awaited event. But is a continuing increase in humans good for the planet in the long run? LINK – world population clock LINK

6. For most of our history, humans were not very numerous, compared with other species. Studies of hunting and gathering societies suggest that the total world population was probably only a few million people before the invention of agriculture and the domestication of animals. The agricultural revolution (around 10,000 years ago) produced a larger and more secure food supply and allowed the human population to grow, reaching perhaps 50 million people by 5000 b.c. The world human population reached 1 billion in about 1800 a.d.

7. As you can see in figure 4.3, human populations began to increase rapidly after about a.d. 1600. Video Link (vlc player)Video Link Many factors contributed to this rapid growth. Increased sailing and navigating skills stimulated commerce and communication among nations. Agricultural developments, better sources of power, and better health care and hygiene also played a role. We are now in an exponential, or J curve, pattern of growth

8. For thousands of years, the number of humans increased very slowly. Archaeological evidence and historical descriptions suggest that only about 300 million people were living at the time of Christ (table 4.1). up until the Middle Ages, populations were mostly limited by disease, famine, and war Rule of Thumb: In exponentially growing populations: Doubling Time = 70/annual % growth For Ex., in a population with a 2% growth rate, doubling time = 70/2 = 35 years

9. Since the time of the Industrial Revolution, when the world population began growing rapidly, individuals have argued about the causes and consequences of population growth. Does environment or culture control human population growth? Thomas Malthus In 1798 Thomas Malthus (1766–1834) wrote An Essay on the Principle of Population, changing the way European leaders thought about population growth. Malthus marshaled evidence to show that populations tended to increase at an exponential, or compound, rate while food production either remained stable or increased only slowly.

10. Eventually human populations would outstrip their food supply and collapse into starvation, crime, and misery. Disease, famine, birth control, etc. Humans are too lazy and immoral to voluntarily regulate birth rates. Malthus converted most economists of the day from believing that high fertility increased gross domestic output to believing that per capita output actually fell with rapidly rising population.

11. Karl Marx Karl Marx presented a different view: Population growth is a symptom rather than a root cause of poverty and other social problems. Real causes of these problems are exploitation and oppression. The way to slow population growth and alleviate many social problems is through social justice. START HERE!

12. Thus, there seems to be two opposing views, that still hold true today Thus, there seems to be two opposing views, that still hold true today First, people should be encouraged (or forced) to reduce birth rates First, people should be encouraged (or forced) to reduce birth rates Andra Pradesh State in India (Case Study, p. 74) coerced individuals to sterilize themselves Amazing drop in fertility rate Second, improving people’s education and income levels should result in lower fertility levels Second, improving people’s education and income levels should result in lower fertility levels Kerala State in India, one of the poorest, has fertility rates comparable to USA!

13. Others argued that technology increases carrying capacity for human beings Technology helped increase food supplies In 1974, world population was @ 3.7 billion people each person averaged 2435 calories/day In 2000, world population was @ 6 billion people each person averaged 2807 calories/day Technological optimists argue that Malthus was wrong in his predictions because he failed to account for scientific progress. Current burst of growth was stimulated by the scientific and industrial revolutions, not human instinct to perpetually grow.

14. Optimists also argue that population growth could bring benefits, such as economic growth. More people mean larger markets, more workers, and increased efficiency due to mass productions. Greater numbers also provide more intelligence and enterprise to overcome problems. Human ingenuity and intelligence will eventually solve the problems This view is shared by many leaders of developing countries! This view is shared by many leaders of developing countries!

15. Terminology Demography encompasses vital statistics about people, such as births, deaths, and where they live, as well as total population size. Fecundity is the physical ability to reproduce, while fertility is the actual production of offspring. The total fertility rate is the number of children born to an average woman in a population during her entire reproductive life. Zero population growth (ZPG) occurs when births plus immigration in a population just equal deaths plus emigration.

18. Factors affecting population growth Fertility varies among cultures and at different times Mortality offsets births Life expectancy is rising worldwide Living longer has profound social implications

19. Fertility rates have declined sharply in every region of the world except Africa over the past 50 years. In the 1960s, total fertility rates above 6 were common in many countries. The average family in Mexico in 1975, for instance, had 7 children. By 2005, however, the average Mexican woman had only 2.6 children. According to the World Health Organization, 61 of the world’s 190 countries are now at or below a replacement rate of 2.1 children per couple. The greatest fertility reduction has been in Southeast Asia, decades.

20. Contrary to what many demographers expected, some of the poorest countries in the world have been remarkably successful in lowering growth rates. Bangladesh, for instance, reduced its fertility rate from 6.9 in 1980 to only 3.0 children per woman in 2005. China’s one-child-per-family policy decreased the fertility rate from 6 in 1970 to 1.8 in 1990 (fig. 4.7). This policy, however, along with a strong preference for sons, has sometimes resulted in abortions, forced sterilizations, and even infanticide. It also has been so successful that the government is now worried about a shortage of workers. By mid century, at least one-third of the Chinese population will be retirees, if current trends continue.

21. According to the view of ----------------------, Humans are too lazy and immoral to voluntarily regulate birth rates. (a) Thomas Malthus (b) Karl Marx (c) Andra Pradesh According to the view of ----------------------, poverty and other social problems are causing population growth results (a) Thomas Malthus (b) Karl Marx (c) Andra Pradesh -------------- is the physical ability to reproduce, while fertility is the actual production of offspring (a) Demography(b) Fecundity(c) total fertility rate Replacement rate is ------------- children per couple (a) 2 (b) 2.1(c) 2.5

22. First is poor, young, and rapidly growing. Less-developed countries. Africa, Asia, Latin America Contain 80% of world population, and will account for 90% of projected growth. Second is wealthy, old, and mostly shrinking. North America, Western Europe, Japan Average age is about 40; life expectancy ~ 90 yr by 2050!! Populations expected to decline. Couples choosing not to have children or one child

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25. Life span is the oldest age to which a species is known to survive. Life expectancy is the average age that a newborn infant can expect to attain in any given society. For most of human history, life expectancy in most societies probably has been 35 to 40 years. This doesn’t mean that no one lived past age 40 but, rather, that many people died at earlier ages (mostly early childhood), which balanced out those who managed to live longer.

26. The twentieth century saw a global transformation in human health unmatched in history. This revolution can be seen in the dramatic increases in life expectancy in most places (table 4.3). Worldwide, the average life expectancy rose from about 40 to 67.2 years over the past 100 years.

27. Life Expectancy $4,000.00 Annual income and life expectancy are strongly correlated up to about $4,000.00 (U.S.) per person, which is generally enough for adequate food, shelter, and sanitation for most people Beyond that, life expectancy levels out at ~ 75 yr males and 85 females!

28. A population growing rapidly by natural increase has more young people than does a stationary population. One way to show these differences is to graph age classes in a histogram, as shown in the figure on the right. In Niger, which is growing at a rate of 3.5 percent per year, 47.8 percent of the population is in the prereproductive category (below age 15). Even if total fertility rates fell abruptly, the total number of births, and the population size, would continue to grow for some years as these young people entered reproductive age. population momentum This phenomenon is called population momentum.

29. By contrast, a country with a relatively stable population will have nearly the same number in most cohorts. Notice that females outnumber males in Sweden’s oldest group because of differences in longevity between sexes. A rapidly declining population, such as Singapore’s, can have a pronounced bulge in middle-age cohorts as fewer children are born than in their parents’ generation.

30. dependency ratio Both rapidly growing countries and slowly growing countries can have a problem with their dependency ratio, or the number of nonworking compared with working individuals in a population. In Niger, for example, each working person supports a high number of children. In the United States, by contrast, a declining working population is now supporting an ever larger number of retired persons.

31. Factors that increase people’s desires to have babies are called pronatalist pressures. Children may be the only source of support for elderly parents in countries without a social security system. Often children are valuable to the family not only for future income but even more as a source of current income and help with household chores. Society also has a need to replace members who die or become incapacitated.  Boys frequently valued more than girls.

33. Populations of North America, Western Europe and Japan are -- (a) Young, (b) rapidly growing(c) expected to decline Annual income and life expectancy are strongly correlated up to about $25,000.00. --------------- have a pronounced bulge in middle-age cohorts as fewer children are born than in their parents’ generation (a) Rapidly growing populations (b) relatively stable population (c) Declining population Which of the following is a pronatalist pressure? (a) male pride (b) social status of large families (c) need for additional family income (d) social taboos regarding birth control (e) all of these are sources of pronatalist pressure

34. Education and income affect the desire for children Highly developed countries. Higher education and personal freedom affect women to not have children. The desire to spend time and money on other priorities limits the number of children. Less-developed countries Feeding and clothing is minimally expensive, adding one more child is negligible.

35. In developing countries, higher income often means families can afford more children, thus fertility often increases. In less-developed countries, adding another child to a family usually does not cost much, while in developed countries, raising an additional child can carry significant costs.

36. There is a model describing “falling death rates and birth rates is usually due to improved living conditions accompanying economic development. It is called DEMOGRAPHIC TRANSITION and has four stages premodern Stage I represents the conditions in a premodern society. In these pre-Developed Country - Poor conditions keep death rates high, thus birth rates are correspondingly high. Stage II in which “ Economic Development” brings better conditions and standard of living thus death rates fall. (urbanizing/industrializing) Birth rates stay constant or even rise. Stage III: in which Death rate is stable and low, but birth rate is falling (mature/industrial) It represents conditions in m any of the most rapidly growing countries in the world, such as Kenya, Yemen, Libya, and Jordan

38. 3- Stage IV represents conditions in developed countries, where the transition is complete and both birth rates and death rates are low. (post-industrial) In countries such as Italy, where fertility levels have fallen below replacement rates, there are now fewer births than deaths, and the total population curve has started to decline. A huge challenge facing countries in the final stage of the demographic transition is the imbalance between people in their most productive years and people who are retired or in their declining years

40. The Indian states of Kerala and Andra Pradesh exemplify two approaches to population growth (see What Do You Think? p. 88).. In Kerala, providing a fair share of social benefits to everyone was the key to completing the demographic transition. This social justice strategy assumes that the world has enough resources for everyone, but inequitable social and economic systems cause maldistributions of those resources.

41. The leaders of Andra Pradesh, on the other hand, adopted a strategy of aggressively promoting birth control, rather than social justice This strategy assumes that better access to birth control is the key to reducing populations, and that social justice is an unrealistic goal

42. A broad consensus reached by the 180 participating countries agreed that : responsible economic development, education and empowerment of women, and high-quality health care (including family planning services) must be accessible to everyone if population growth is to be slowed.

44. Most demographers believe that world population will stabilize sometime during the twenty-first century. When we reach that equilibrium, the total number of humans is likely to be somewhere around 8 to 10 billion.

45. The United Nations Population Division projects four population scenarios The optimistic (low) projection suggests that world population might stabilize by about 2030 and then drop back below current levels. This is not likely. This is not likely. The medium projections suggest that growth could continue until at least 2050, at which point the total world population could be 11 to 13 billion.

46. 1. About how many years of human existence passed before the world population reached its first billion? What factors restricted population before that time, and what factors contributed to growth after that point? 2. Describe the pattern of human population growth over the past 200 years. What is the shape of the growth curve (recall chapter 3)? 3. Define ecological footprint. Why is it helpful, but why might it also be inaccurate? 4. Why do some economists consider human resources more important than natural resources in determining a country’s future?

47. 5. In which regions of the world will most population growth occur during the twenty-first century? What conditions contribute to rapid population growth in these locations? 6. Define crude birth rate, total fertility rate, crude death rate, and zero population growth. 7. What is the difference between life expectancy and life span? Why are they different? 8. What is the dependency ratio, and how might it affect the United States in the future? 9. What factors increase or decrease people’s desire to have babies? 10. Describe the conditions that lead to a demographic transition.