8 Human Population Chapter Objectives

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Chapter Objectives This chapter will help students:

Perceive the scope of human population growth Assess divergent views on population growth Evaluate how human population, affluence, and technology affect the environment Explain and apply the fundamentals of demography Outline and assess the concept of demographic transition

Describe how wealth and poverty, the status of women, and family planning affect population growth

Characterize the dimensions of the HIV/AIDS epidemic Link population goals to sustainable development goals

Lecture Outline I. Central Case: China’s One-Child Policy

A. The People’s Republic of China is the world’s most populous nation, home to one-fifth of the 6.9 billion people living on Earth.

B. Under Mao Zedong’s leadership, improved food production and distribution and better medical care have allowed China’s population to swell, causing environmental problems, and raising the TFR to 5.8.

C. The government instituted a population-control program in the 1970s.

1. The program started with education and outreach efforts encouraging people to marry later and have fewer children, and increasing the accessibility of contraceptives and abortion.

2. In 1979, the government decided to institute a system of rewards and punishments, enforcing a one-child limit per family.

3. In 1984, the policy was relaxed, exempting rural areas and certain minorities, thus minimizing opposition.

D. China’s growth rate is down to 0.5%; however, there have been unintended consequences of the program, such as widespread killing of female infants and an unbalanced sex ratio.

II. Our World at Seven Billion

A. The human population is growing rapidly.

1. Our global population grows by 80 million people each year.

2. Since 1975, the world’s population has added one billion humans every 12 years.

3. Our unprecedented growth is due to exponential growth.

4. For much of the 20th century, the growth rate of human population rose from year to year.

B. Is population growth a problem?

1. Our ongoing burst of population growth has resulted from technological innovations, improved sanitation, better medical care, increased agricultural output, and other factors that have brought down death rates and infant mortality rates.

2. In the past, population was universally regarded as a good thing.

3. Thomas Malthus and Paul and Annie Ehrlich believed differently, that there are limits to human population growth.

4. There are many people today who deny that population growth is a problem.

5. Under the Cornucopian view, resource depletion as a consequence of greater numbers of people is not a problem if new resources can be found to replace the depleted resources.

6. Environmental scientists argue that not all resources are replaceable by others once they are depleted.

7. Even if resource substitution could enable indefinite population growth, could we maintain the quality of life that we would desire, or would our descendants have less space, less food, and less material wealth than the average person does today?

C. Some national governments now fear falling populations.

1. Many governments have found it difficult to let go of the notion that population growth increases a nation’s economic, political, and military strength.

2. When birth rates decline, a population grows older.

D. Population is one of several factors that affect the environment.

1. The IPAT model represents how humans’ total impact (I) results from the interaction among three factors—population (P), affluence (A), and technology (T): I = P × A × T.

2. A sensitivity factor (S) can be added to the equation to denote how sensitive a given environment is to human pressures: I = P × A × T × S.

3. Impact can generally be boiled down to either pollution or resource consumption.

4. Modern-day China shows how all elements of the IPAT formula can combine to result in tremendous environmental impact in very little time.

III. Demography

A. Earth has a carrying capacity for us.

1. The environment has a carrying capacity for our species, just as it does for every other.

2. We have repeatedly raised this carrying capacity by developing technology to overcome the natural limits on our population growth.

3. The most rigorous estimates of carrying capacity range from 1–2 billion people living prosperously in a healthy environment, to 33 billion living in extreme poverty in a degraded world of intensive cultivation without natural areas.

B. Demography is the study of human population.

1. The application of population ecology principles to the study of statistical change in human populations is the focus of the social science of demography.

2. Demographers study population size, density, distribution, age structure, and sex ratio, as well as birth and death rates, immigration and emigration.

3. Population size is the absolute number of individuals.

4. People are distributed unevenly over our planet.

a. This uneven distribution means that certain areas bear far more environmental impact than others.

b. At the same time, areas with low population density are sensitive, and thus vulnerable to environmental impacts.

5. Age structure diagrams show the number of people in each age class and are especially valuable to demographers in predicting future dynamics of a population.

a. A large concentration of individuals in young age groups portends a great deal of reproduction.

6. The ratio of males to females, the sex ratio, can also affect population dynamics.

a. The naturally occurring sex ratio in human populations at birth features a slight preponderance of males.

b. A greatly distorted sex ratio can lead to problems. In China, selective abortion of female fetuses has skewed the natural sex ratio.

C. Population change results from rates of birth, death, immigration, and emigration.

1. In today’s world, immigration and emigration are playing an increasingly large role because of the flow of refugees.

2. In recent decades, falling growth rates in many countries have led to an overall decline in the global growth rate. This growth rate has declined partially because of a steep drop in birth rates.

D. Total fertility rate influences population growth.

1. The total fertility rate (TFR) is the average number of children born per woman during her lifetime.

2. Replacement fertility is the TFR that keeps the size of a population stable; for humans, it is 2.1.

3. A lower infant mortality rate has reduced people’s tendency to conceive many children in order to ensure that at least some survive.

4. Many other social factors play a role in reducing the emphasis on child rearing.

5. The natural rate of population change is the change due to birth and death rates alone, excluding migration.

E. Many nations have experienced the demographic transition.

1. Life expectancy is the average number of years that an individual in a particular age group is likely to live.

2. Demographic transition is a theoretical model of economic and cultural change that explains the trend of declining death and birth rates that occurs when nations become industrialized.

a. The first stage, the pre-industrial stage, is characterized by conditions in which both death rates and birth rates are high.

b. In the next stage, the transitional stage, death rates decline and birth rates remain high.

c. The industrial stage creates employment opportunities, particularly for women, causing the birth rate to fall.

d. In the final stage, the post-industrial stage, both birth rates and death rates remain low and populations stabilize or decline slightly.

F. Is the demographic transition a universal process?

1. This transition has occurred in many European countries, the United States, Canada, Japan, and several other developed nations over the past 200–300 years.

2. It is a model that may or may not apply to all developing nations as they industrialize now and in the future.

IV. Population and Society

A. Birth control is a key approach for controlling population growth.

1. Birth control limits the number of children one bears, by reducing the frequency of pregnancy.

2. Birth control relies on contraception, the deliberate attempt to prevent pregnancy despite sexual intercourse.

3. Family planning is the effort to plan the number and spacing of one’s children, so as to assure children and parents the best quality of life possible.

4. In many societies, planning for pregnancy is hindered by religious doctrine or cultural influences, so contraceptives are denied to people who might otherwise use them.

B. Empowering women reduces fertility rates.

1. Fertility rates have dropped most noticeably in nations where women have gained improved access to contraceptives and to family planning

2. Unfortunately, many women still lack the information and personal freedom of choice to allow them to make their own decisions about when to have children and how many to have.

3. In societies in which women are freer to make reproductive decisions, fertility rates have fallen, and the children are better cared for, healthier, and better educated.

C. Population policies and family-planning programs are working around the globe.

1. India was the first country to implement population control policies. After strident policies in the 1970s led to the downfall of the government, India’s efforts have been more modest and far less coercive, focusing on family planning and reproductive healthcare to better manage the population, which seems set to overtake China and become the world’s most populous nation by the year 2030.

2. The government of Thailand has reduced birth rates and slowed population growth, due to its education-based approach to family planning and the increased availability of contraceptives

3. Brazil, Mexico, Iran, Cuba, and many other developing countries have instituted programs to reduce their population growth that entail setting targets and providing incentives, education, contraception, and reproductive health care.

4. In 1994, the United Nations hosted a conference in Cairo on population and development, at which 179 nations endorsed a platform calling for all governments to offer universal access to reproductive health care within 20 years.

5. However, worldwide funding for family planning fell by well over a third in the decade following the Cairo conference.

D. Poverty is correlated with population growth.

1. The causality is thought to operate in both directions: poverty exacerbates population growth, and rapid population growth worsens poverty.

2. This is unfortunate from a social standpoint, because these people will be added to the nations that are least able to provide for them.

E. Consumption from affluence impacts the environment.

1. Affluence and consumption are spread unevenly across the world, and wealthy societies generally consume resources from regions far beyond their own.

2. Individuals in affluent societies leave a larger ―ecological footprint‖ than those in less affluent societies.

3. Because our footprint exceeds our biocapacity (amount of biologically productive land and sea available to us) by 30% worldwide, we are running a global ecological deficit, gradually draining our planet of its natural capital and its long-term ability to support our civilization.

F. The wealth gap and population growth contribute to conflict.

1. The richest 20% of the world’s people uses 86% of the world’s resources.

2. As the gap between rich and poor grows wider and as the sheer numbers of those living in poverty continue to increase, it seems reasonable to predict increasing tensions between the ―haves‖ and ―have-nots.‖

G. HIV/AIDS is taking a major toll on African populations.

1. Of the world’s 33 million people infected with HIV/AIDS as of 2008, two- thirds live in sub-Saharan Africa.

2. The AIDS epidemic is unleashing a variety of demographic changes.

3. Premature deaths, of both infants and young adults, are reducing the average life expectancy in African nations.

4. HIV is well-established in the Caribbean and in Southeast Asia, and it is spreading in eastern Europe and central Asia.

H. Demographic change has social and economic repercussions.

1. In sub-Saharan Africa, AIDS is undermining the ability of developing countries to make the transition to modern technologies because it is taking away many of the youngest and most productive members of society.

2. Governments of AIDS-infected countries are experiencing demographic fatigue.

3. We may finally be turning the corner on this challenge, thanks to government policy, international collaboration, medical research, nonprofit aid groups, and the grassroots efforts of patients and their advocates.

I. Sustainable development and population goals go hand-in-hand.

1. If humanity’s overarching goal is to generate a high standard of living and quality of life for all people, then developing nations must find ways to slow their population growth.

2. However, those of us living in the developed world must also be willing to reduce our consumption.

V. Conclusion

A. Although global populations are still growing, the rate of growth has decreased nearly everywhere, and some countries are even seeing their population decline.

B. There has been progress in expanding women’s rights worldwide. In addition to the clear ethical progress of this development, it also helps to slow population growth.

C. True sustainability demands that we stabilize our population size in time to avoid destroying the natural systems that support our economies and societies.

Key Terms birth control Malthus, Thomas contraception Millenium Development Goals demographers natural rate of population change demographic transition post-industrial stage demography pre-industrial stage family planning replacement fertility industrial stage total fertility rate (TFR) IPAT model transitional stage life expectancy

Teaching Tips

1. The Population Connection is the new name for the organization that used to be called Zero Population Growth (ZPG). Its website (www.populationconnection.org) has a variety of fact sheets and programs, including a campus outreach program for colleges and universities. The organization will also present free workshops and trainings at your location and at conferences.

2. Ask each student to adopt a country and research the status of its population, including size, crude birth rate, crude death rate, life expectancy, infant mortality, annual growth rate, and age structure. Current information can be found on the ―People Facts and Figures‖ site at www.os-connect.com/pop.

To make this an interactive activity, require each student to present the information to the class. Once presentations have been made, discuss the similarities and differences among the countries. This can lead to a discussion of the characteristics of ―developed countries‖ versus ―developing countries.‖

3. Death rates have dramatically declined in the United States over the past 100 years. To examine this change in greater detail, students can conduct a study on percent survival. First, students will collect data from a local cemetery (preferably one in which people were buried before 1900) and compare those data to data from current newspaper obituary pages. Ask each student to record the age at death for 20 individuals from each source. Students will then organize the data according to 10-year age categories as shown below. There will be two tables—one for cemetery data and the other for obituary data. Percent survival is then calculated for each age category.

Age Group Number that Died Percent Surviving 0–10 A = (20 - A)/20 x 100 11–20 B = [20 - (A + B)] ÷ 20 x 100 21–30 C = [20 - (A + B + C)] ÷ 20 x 100 31–40 D etc. 41–50 E 51–60 F 61–70 G 71–80 H 81–90 I 91–100 J Over 100 K = [20 - (sum of A . . . K)] ÷ 20 x 100

The resulting percent survival values can be graphed to show a survivorship curve, with age classes on the x axis and the percent surviving values on the y axis. In general, there are three classes of survivorship curves: Type I, Type II,

4. Use resources from the Population Reference Bureau (www.prb.org) for classroom presentations and activities. The graphics bank contains over 100 PowerPoint slides with illustrations of population data. The graphics cover international population and health topics (family planning, HIV/AIDS, population trends,and so on). The website also links to the Center for Public Information on Population Research, the Interagency Gender Working Group, and the Population and Health InfoShare website. The link to the World Population Data Sheet contains the latest population estimates, projections, and other key indicators for 200 countries.

5. Initiate a discussion with these questions: ―Have you made any decisions regarding children in your future?‖ ―Has any information you’ve learned this term caused you to reconsider future plans for careers, family, or places that you might choose to live?‖ By framing these questions as open-ended and exploratory rather than accusatory, often very productive, insightful, and engaging discussions are possible. It is essential that ground rules for a critical- thinking classroom be set prior to discussions that contain sensitive topics. Ground rules include: a safe space to share and reflect on what is offered by others; disagree with a person’s viewpoint, but remain respectful of the person who owns that viewpoint; and remain open-minded to the views of others by being a good listener.

6. Whether your course is small or large, handing out lecture notes, assignments, graded papers and the like take up valuable class time. Here are some tips to minimize that time:

• Use two magazine/periodical files and an inbox. Label the file boxes ―Past Handouts‖ and ―Graded Papers,‖ and place them on a table or counter near the door.

• Put any handouts for the current day on the table in front of the boxes.

• Students bring assignments to the table and place them in the inbox. If any students missed the last session, they can get the materials from the Past Handouts box. They can check the Graded Papers box for prior assignments you have handed back, and they can pick up today’s handouts in class.

• At the end of class, pick up the day’s handout, place it in a labeled folder, and put it in the Past Handouts box. Pick up any new student assignments from the inbox. Place the boxes in a cabinet or drawer until the next session.

• You need an additional Graded Papers box for each section of a course. The Past Handouts box is the same, and you will empty the inbox at the end of each class.

123 Copyright © 2011 Pearson Education, Inc • If the class is larger than 50 students, you may find it easier to have several Graded Papers boxes and several inboxes, labeled A–B, C–D, E–J indicating students’ last names, and so on. Spread the sets of boxes out around the perimeter of the classroom in a standard fashion so that students know where their cohorts’ boxes are located.

• Remind students, as necessary, that they can access the boxes before class, during a break, or after class, but that riffling through the boxes during class time is not desirable.

Additional Resources

Websites

1. The Effect of China’s One-Child Family Policy after 25 Years, New England Journal of Medicine (http://content.nejm.org/cgi/content/full/353/11/1171)

This link is to an article in the New England Journal of Medicine reviewing China’s attempt to control human population.

2. Country Studies: China—Population Control Programs, Federal Research Division, Library of Congress (http://countrystudies.us/china/34.htm)

This website is part of the Country Studies/Area Handbook Series, sponsored by the U.S. Department of the Army between 1986 and 1998, which discusses China’s population control policy. There are also links to more current information.

3. Population and Economic Household Topics, U.S. Census Bureau (www.census.gov/population/www)

This gateway provides population clocks for the United States and the world, along with information about births, fertility, deaths, and migration in the United States.

4. State of the World Population, United Nations Population Fund (www.unfpa.org/swp/swpmain.htm)

This is a report by the United Nations Population Fund, the world’s largest international source of funding for population and reproductive health programs. Access to databases, maps, graphs, and previous years’ reports is available.

5. UNAIDS, Joint United Nations Programme on HIV/AIDS (www.unaids.org/en) This resource provides access to information, databases, and publications concerning the global HIV/AIDS epidemic.

This organization provides sobering analyses of the global human population dynamic. Topics include revisiting the demographic transition model, foreign aid, and the future of agriculture in meeting human nutrition needs. CCN can also be reached at: 2000 P Street NW, Suite 31, Washington, DC 20036. 800- 466-4866.

Audiovisual Materials

1. Jam Packed, 1997, video by Population Communications International and distributed by The Video Project (http://videoproject.com)

This program looks at the human population growth problem from a young person’s point of view.

2. Not the Numbers Game, 1997, video produced by Emily Marlow and Jenny Richards for Television Trust for the Environment and distributed by Bullfrog Films (www.bullfrogfilms.com)

This six-part series looks at how women are solving population and development problems in Bosnia, Cambodia, India, Indonesia, Peru, and Uganda.

3. Population Six Billion, 1999, video distributed by Films for the Humanities and Sciences (www.films.com)

This program addresses life in developing nations while providing case studies of population control initiatives in Vietnam, Uganda, and Mexico which include family planning, HIV/AIDS testing and counseling, and sex education.

4. Paul Ehrlich and The Population Bomb, 1996, video distributed by Films for the Humanities and Sciences (www.films.com)

Based on Ehrlich’s book The Population Bomb, this program features archival footage from around the world, as well as interviews with Ehrlich, his colleagues, and his critics.

Weighing the Issues: Facts to Consider

China’s Reproductive Policy

Facts to consider: Benefits of a reproductive policy such as China’s might include a greater ability to provide food, health care, housing, and education, as well as reduced environmental pressure. Problems might include social and legal punishment for people who do not follow the policy; reduction in personal choice

125 Copyright © 2011 Pearson Education, Inc about family decisions; pressure to favor one gender over another; and pressure on industry, government finances, health care, families, and military forces because fewer working-age people are available.. Alternative ways of dealing with the resource demands of a quickly growing population include finding new resources to replace depleted ones, both within the country and abroad (which may greatly increase environmental pressure as resources become increasingly scarce); using rewards for smaller families while refraining from punishments; and using more efficient technologies to reduce resource-intensive processes andpollution.

Consequences of Low Fertility?

Facts to consider: A below-replacement fertility rate means that the population is aging. Changes in the age composition of the population will alter patterns of consumption. Most notably, an increase in the mean population age will trigger an increasing demand for healthcare services. Working-age people will need to supply the productivity and finances required to support the higher proportion of older, retired people. Further observations may also be mentioned, based on a broader student understanding of economics and social issues.

Students may discuss increased immigration to provide a labor force; a reduced labor force, leading to wage increases and inflation, thus decreasing the purchasing power of retirees; greater savings rates as families spend less on dependents; lower savings rates as older people, lacking income, spend their savings; and increases in the retirement age so as to reduce the demands on public welfare, as fewer younger workers are putting in funds while more older workers receive entitlements and services.

Abstaining from International Family Planning?

Facts to consider: The first of these questions requires an individual response. The second question also requires a personal response, but students can approach it from a consumption/tragedy of the commons perspective. In responding to the final question, students may use some examples from the textbook, such as increased education and the availability of contraceptives; fewer punitive measures and more positive incentives to adhere to government policy; international monitoring groups, to ensure that funds are used according to treaties; and measures assuring that actions taken by those in charge of family planning do not discriminate or penalize minority ethnic groups.

Mapping Our Population’s Environmental Impact

Observation: Burgeoning numbers of people are making heavy demands on Earth’s natural resources and ecosystem services.

Hypothesis: Human overuse of NPP can be quantified. Evidence can show that we diminish resources for other species, alter habitats, communities, and ecosystems, and that we threaten our future ability to derive ecosystem services. Human impact can be judged by comparing human impacts in relation to the total ―potential‖ NPP.

Experiment: Haberl’s team began with a well-established model that maps how vegetation varies with climate across the globe. The team used it to produce a detailed world map of ―potential NPP‖—vegetation that would exist if there were no human influence. They then gathered data for the year 2000 on crop harvests, timber harvests, grazing pressure, and other human uses of vegetation from the U.N. Food and Agriculture Organization’s (FAO) global databases and other sources. They also gathered data on how people affect vegetation indirectly, such as through fires, erosion, and soil degradation, and other changes due to land use. The researchers calculated the proportion of NPP appropriated by people by dividing the amounts used up in these impacts by the total ―potential‖ amount.

Results: Haberl’s group concluded that people harvest 12.5% of global NPP, and reduce it 9.6% further through land use and 1.7% further through fires. This makes us responsible for using up fully 23.8% of the planet’s NPP—a staggeringly large amount for just a single species! Half of this use occurred on cropland, where 83.5% of NPP was used. In urban areas, 73.0% of NPP was consumed, while 19.4% was used on grazing land, and 6.6% in forests. A global map of NPP consumption was produced.

Fertility Decline in Bangladesh

Observation: In Bangladesh—one of the most densely populated countries on the planet—fertility declined dramatically from the late 1970s through the 1990s despite high rates of poverty, illiteracy, and gender inequality.

Hypothesis: The Bangladeshi government and international aid organizations began an aggressive campaign in the mid-1970s to provide women with access to and information about contraceptives.

127 Copyright © 2011 Pearson Education, Inc Experiment: Researchers measured the impact of outreach efforts on contraceptive use and fertility rates in Matlab, an isolated rural area in Bangladesh with a high- intensity family-planning outreach project. Matlab was compared to a similar government-run program, which had a lower amount of training, services, and community visits.

Results: In 1988, 10 years after the study began, Matlab Project director James Phillips and his colleagues reviewed a decade’s worth of data collected by the highly organized health surveillance system already in place. They found that contraceptive use in Matlab was higher and fertility was lower than in the comparison area. The results suggested that Bangladesh’s success was due to a combination of widely available contraceptives and socially appropriate family planning services, both of which were present in an intensified form in Matlab.

Question: Why was Matlab so successful in reducing fertility rates?

Hypothesis: Frequent visits from healthcare workers helped to convince women that small families were desirable.

Study: Mary Arends-Kuenning of the University of Michigan surveyed families and visiting health workers about the healthcare workers’ visits.

Results: Arends-Kuenning and her colleagues found no correlation between patients’ perception of family size and the number of visits made by healthcare workers, in either the Matlab study area or the control area with the government-run program. It was proposed that the reason for the Matlab Project’s success was that it helped women to realize an already-existing desire to have fewer children by providing readily available contraceptives and education.

Answers to End-of-Chapter Questions Testing Your Comprehension

1. The human global population is approximately 6.7 billion people, with about 220,000 added daily.

2. In many cases, humans have been able to substitute one resource for another, thereby avoiding environmental limitations at least temporarily. As to how long this can be sustained, answers will vary.

3. Environmental scientists are generally convinced that the effects of resource limitation cannot be avoided forever (i.e., that resources are not infinitely substitutable). Cornucopians take the opposing view. Population growth is a problem to the extent that it leads to crowding, resource depletion, reduced standards of living, and environmental degradation.

4. The IPAT model says that our Impact on the environment is a function of

128 Copyright © 2011 Pearson Education, Inc Population size, per capita Affluence, and our Technological choices. Technology can either increase or decrease Impact—for example, choosing a bicycle versus a sport utility vehicle for transportation, or choosing a compact fluorescent lighting fixture versus an incandescent one.

5. Demographers study population size, density, distribution, age structure, sex ratio, and rates of birth, death, immigration, and emigration. Each of these help to determine our environmental impact, because they all affect P in the IPAT model.

6. Total Fertility Rate (TFR) is the number of children the average woman in a population will bear during her lifetime. The replacement TFR is 2.1 because we have an approximately 50:50 sex ratio (two-parent couples) and there is some risk of death during infancy and childhood (approximately 0.05 per child). Europe’s TFR is significantly below the replacement rate of 2.1, and so European populations are beginning to decline in size.

7. Fertility rates fall in societies where families no longer rely heavily on children for their economic productivity and for parental security in old age. They also fall when society comes to the realization that the mortality rate has fallen, and that their children are highly likely to survive to adulthood. All these trends are taking place in nations that are industrialized and becoming more affluent.

8. During the transitional stage of the demographic transition process, death rates have fallen but birth rates are still high. This results in a high population growth rate. As birth rates fall to equal the low death rates, the population growth rate falls toward zero.

9. Studies show that in many societies, women feel coerced into giving birth to more children than they would choose to have. Moreover, poor educational opportunities for women in many nations limit their professional opportunities and encourage them to stay home and raise children. Family planning programs provide information on birth control and on how to have a desirable number of children that a family can support.

10. Poorer societies tend to place a higher economic value on their children, and thus have more of them. The large and growing populations that result have an increasing impact on the environment because of the increase in the P term of the I = PAT relationship. Increased affluence tends to be accompanied by decreased population growth rates, but the increase in the A term can also cause an increase in the total impact on the environment due to an increase in resource consumption.

Total

Personal Impact Affluence Impact (national

Population (per capita (per capita footprint, Nation (millions of income, in footprint, in in millions people) GNI PPP) ha/person) of ha) Belgium 10.8 $34,760 5.1 55

Brazil 193.3 $10, 070 2.4 464

China 1,338.1 $6,020 2.1 2810

Ethiopia 85 $870 1.4 119

India 1,188.8 $2,960 0.9 1070

Japan 127.4 $35,220 4.9 624

Mexico 110.6 $14,270 3.4 376

Russia 141.9 $15,630 3.7 525

United 309.6 $46,970 9.4 2910

States

1. See the rightmost column above. 2. The graph would show a strong positive correlation, because affluence has resulted largely from resource consumption. 3. The graph would show a positive correlation, but not a very strong one, because affluence as well as population drives total impact. 4. The graph would show a positive correlation, but not a very strong one, because population as well as affluence drives total impact. The United States has an extremely high total impact because it has one of the largest populations in the world and because it is one of the most affluent nations in the world. 5. As one of many possible examples, coal-fired power plants have increased air pollution in the United States, but scrubbers and clean-coal technologies are now reducing pollution from these plants.