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Randy Olson/National Geographic/SuperStock Learning Objectives After studying this chapter, you should be able to: • Explain what the field of demography and demographics is about and how demographers use concepts like birth rates, death rates, and fertility rates to study changes in population over time. • Discuss the range of population forecasts for the decades ahead and the factors that help explain the variation in those forecasts. • Explain the I 5 PAT concept and how it shifts the focus of the population-environment debate from one solely focused on human numbers to a broader discussion of the role of affluence and technology in environmental degradation. • Discuss the ways in which the combination of increased family planning services and improvement in the status of women in society helped the Asian nation of Bangladesh achieve remarkable reductions in fertility rates and population growth. Human Population Dynamics 2 CN CT CO_TX CO_BL CO_CRD CO_LO ben85927_02_c02.indd 63 1/20/14 2:32 PM InTro Duc TIon Pre-Test 1. Which stage is characterized with an equal birth rate and death rate in developing countries? a. Pre-industrial stage b. Transitional stage c. Industrial stage d. Post-industrial stage 2. Which country has the fastest growing amount of carbon emissions from fossil fuels? a. u nited States b. Africa c. England d. c hina 3. Living standards and rates of consumption in much of Africa are very low, and yet some demographers and environmental scientists are concerned about the future environmental impacts of population on that continent. Based on the I 5 PAT formula this is because Africa has a. a declining A factor. b. a rising T factor. c. a rising A factor. d. a rising P factor. 4. Beyond the availability of family planning and contraceptive services, demographers know that better education and opportunities for young girls and women can have a powerful impact on fertility rates. This is because a. well-educated women tend to have more children. b. well-educated women tend to have fewer children. c. well-educated women tend not to get married. d. well-educated women can read the instructions on contraceptive packages. Answers 1. d. Post-industrial stage. The answer can be found in section 2.1. 2. d. c hina. The answer can be found in section 2.2. 3. d. a rising P factor. The answer can be found in section 2.3. 4. b. well-educated women tend to have fewer children. The answer can be found in section 2.4. Introduction During Paleolithic, or stone tool, times humans had relatively little advantage over other ani- mals on the savanna. Survival was fragile, people died young, and populations stayed small.

But humans were smart. Tribal bonds became strong, people learned to cooperate for the common good, and we survived those perilous times.

Then, about 50,000 years ago, tool technology began to show rapid improvements. Light, sharp, streamlined spear points replaced the primitive hand axe, and the bow and arrow increased the range at which a hunter could subdue his prey. Humans developed the use of language, which precipitated cooperation among hunters and gatherers and led to increased PT PT_NLF PT_NL PT_ANS H1 Running head H1 TX section title section number section title ben85927_02_c02.indd 64 1/20/14 2:32 PM InTro Duc TIon efficiency when planning hunting strategies. By 12,000 years ago, people started to settle in communities and to practice agriculture, and the human population began to grow rapidly.

Today, the human race and its resource demands are many times larger than they were only a few hundred years ago. As a result, one of the most serious questions environmental sci- entists ask today is whether current population growth trends are sustainable on a planet with finite resources. In order to answer that question it’s important to first understand the field of demography or demographics—the statistical study of population change. Section 2.1 introduces the concept of population growth and demographics as a way of illustrating how even small initial changes to population growth rates can build over time to result in dramatic increases in population size. Section 2.2 shifts the focus to the future and, by apply - ing the tools of demography learned in Section 2.1, discusses some of the changes occurring in human fertility around the world and what this might mean to future population growth.

Section 2.3 introduces something known as the I 5 PAT formula, a tool used by some envi- ronmental scientists to illustrate how rates of material consumption and affluence combine with population size and technology use to determine the overall environmental impact of a given population. Section 2.4 uses the case of the South Asian nation of Ba\ ngladesh to illustrate how population growth can be brought under control in ways that are humane, culturally sensitive, and focused on the health and well-being of the families involved.

A note of caution is also in order at the beginning of a chapter on human population. Any discussion of human fertility, population control, and family planning will inevitably touch on sensitive subjects of religious beliefs, cultural mores and customs, and the politics of birth control, abortion, and fertility regulation. The purpose of this chapter is not to convince you to take one side or another on any of these issues. rather, the goal here is to help you understand: • How changes to birth rates, death rates, emigration, and immigration change popu - lation over time (i.e., the study of demography); • How demography can help us develop projections of future population levels in the decades ahead; • How rates of consumption, affluence, and the use of technology combine with changes in human numbers to determine the overall impact of a given population on the environment; and • How different approaches to population policy have been tried in different parts of the world with varying degrees of impact and success.

Because this book uses an anthology approach, compiling and presenting the writing of oth - ers, it occasionally introduces language and ideas that some of you may find disagreeable.

However, if you focus on the learning objectives presented at the start of the chapter and the list of points above, you will be able to acquire the knowledge you need to comprehend and debate population issues as an educated individual. ultimately, from an environmental science perspective, the issues of population change and population policy are important because virtually all human activity impacts the natural environment. As such, the more of us there are, the greater are our impacts. It’s essential then that as a student of environmental science you are presented with and challenged to understand issues of human population growth over time. ben85927_02_c02.indd 65 1/20/14 2:32 PM SEcTIon 2.1 Po PuLATI on Gro WTH AnD DEmo GrAPHI cS 2.1 Population Growth and Demographics The following excerpt from AP Environmental Science chapter 6—History and Global Distribu - tion, Encyclopedia of Earth explains that for much of history the human race has lived a precari - ous existence. Disease, natural disasters, and famines kept human population low and, on occa- sion, close to extinction. However, in just the past 200 years, human population numbers have grown from roughly one billion to over seven billion. This population explosion is due mainly to better nutrition, advances in health care, and improved sanitation practices. These advances have doubled human life expectancy and have sharply decreased death rates. The study of how human populations change over time is known as demographics, and demographers examine trends in birth rates, death rates, and other factors to predict future population trends.

Some of the same concepts of population biology or population dynamics that applied to other species in section 1.4 also apply to humans. When conditions are right, human populations can experience exponential growth, doubling from 1 to 2 units, 2 to 4, 4 to 8, 8 to 16, 16 to 32, and so on. For most of human history, however, such conditions did not apply. In fact, it has just been in the last few hundred years that conditions have favored exponential growth of the human population on this scale .

Demographers typically measure population changes by examining births and deaths per 1,000 people in a given time period. If a random group of 1,000 people from a population were locked away in a gymnasium or shipped to a remote island for a year, we could determine the growth rate and final population of that group by looking at births and deaths over that time. For exam - ple, if 20 children were born over the course of that year (some of the women picked at random may have already been pregnant) and 10 individuals in the group were to die, the so-called natural rate of population change would be (20 2 10)/1,000 3 100 5 1%. In reality, popula- tions are not locked away in gymnasiums or stranded on remote islands, so demographers also have to consider factors such as immigration and emigration in determining population change .

The key variables in determining changes to a population thus turn out to be birth rates (births per 1,000 people), death rates (deaths per 1,000 people), and fertility rates (the average num - ber of children a woman will have over her lifetime). Throughout most of human history, fer - tility and birth rates were typically quite high, with fertility rates of 6–8 children per woman and birth rates of 40 per 1,000 annually. Because death rates were also quite high, also around 40 per 1,000, human population numbers did not grow very much or at all. The first variable to change significantly within the past few hundred years was death rates. This was due to advances in science, medicine, sanitation, and nutrition—all of which helped people live longer lives. As death rates declined, fertility rates and birth rates stayed the same, and human popula - tions began to grow .

Eventually, however, fertility rates started to decline as did the birth rate. When and if the birth rate declines to the point where it equals the death rate, population will begin to move toward stabilization. This process of declining death rates, followed by declining birth rate—with popu - lation growth occurring in the interim—is known as the demographic transition . Most indus- trialized countries like the United States have already completed a demographic transition; ben85927_02_c02.indd 66 1/20/14 2:32 PM SEcTIon 2.1 Po PuLATI on Gro WTH AnD DEmo GrAPHI cS Apply Your Knowledge The concept of exponential growth provides a powerful reminder of just how fast human numbers have grown in the past 200 years. For this exercise imagine that you have a chess- board and a large bag of chocolate candies. on the first square of the chess board place one piece of candy and then on each subsequent square double the number of pieces of candy— two on square 2, four on square 3, eight on square 4, and so on. How many pieces of candy are you putting on square 5? How many on square 10? What do you think would happen by the end of the board, square 64? Graph what this pattern might look like using a simple X-Y graph like that in Figure 2.1. What does this tell you about the power of doubling? How relevant is an understanding of this concept to the study of human population change?

(continued) however, many developing countries are still in the midst of one. Thus, it is in these regions that most of the world’s population growth continues to occur. The understanding gained in this sec - tion of demography and demographics will help you better grasp the discussion in subsequent sections of how population growth impacts the environment and what’s being done to try and bring population growth under control.

By Peter Saundry, Topic Editor A population is a group of individuals living together in a given area at a given time. changes in populations are termed population dynamics. The current human population is made up of all of the people who currently share the earth. The first humans walked the planet mil - lions of years ago. Since that time, the number of humans living on the planet and where they live has constantly changed over time. Every birth and death is a part of human population dynamics. Each time a person moves from one location to another, the spatial arrangement of the population is changed, and this, too, is an element of population dynamics. While humans are unique in many ways as a species, they are subject to many of the same limiting forces and unexpected events of all populations of organisms.

Population Growth Human populations are not stagnant. They naturally change in size, density and predomi - nance of age groups in response to environmental factors such as resources availability and disease, as well as social and cultural factors. The increases and decreases in human popu - lation size make up what is known as human population dynamics. If resources are not limited, then populations experience exponential growth. A plot of exponential growth over time resembles a J curve. Absolute numbers are relatively small at first along the base of the J curve, but the population rapidly skyrockets when the critical time near the stem of the J curve is reached. ben85927_02_c02.indd 67 1/20/14 2:32 PM SEcTIon 2.1 Po PuLATI on Gro WTH AnD DEmo GrAPHI cS Apply Your Knowledge (continued) Figure 2.1: Exponential growth numbers grow quickly under exponential growth. Number of Candies 0 50 150 10 0 200 250 300 350 400 450 500 550 600 1 2 3 4 5 6 7 8 9 10 Square For most of the history of modern humans ( Homo sapiens), people were hunter-gatherers.

Food, especially meat from large mammals, was usually plentiful. However, populations were small because the nomadic life did not favor large family sizes. During those times, the human population was probably not more than a few million worldwide. It was still in the base of the J growth curve.

With the end of the last Ice Age, roughly 10,000 years ago, the climates worldwide changed, and many large mammals that had been the mainstay of human diet became extinct. This forced a change in diet and lifestyle, from one of the nomadic hunter-gatherer to that of a more stationary agricultural society.

Humans began cultivating food and started eating more plants and less meat. Having larger families was possible with the more stationary lifestyle. In fact, having a large family increas - ingly became an asset, as extra hands were needed for maintaining crops and homes. As agri - culture became the mainstay of human life, the population increased.

As the population increased, people began living in villages, then in towns and finally in cities.

This led to problems associated with overcrowded conditions, such as the build up of wastes, poverty and disease. Large families were no longer advantageous. Infanticide [intentionally killing an infant] was common during medieval times in Europe, and communicable diseases ben85927_02_c02.indd 68 1/20/14 2:32 PM SEcTIon 2.1 Po PuLATI on Gro WTH AnD DEmo GrAPHI cS also limited the human population numbers. Easily spread in crowded, rat-infested urban areas, Black Death, the first major outbreak of the Bubonic Plague (1347–1351) drastically reduced the populations in Europe and Asia, possibly by as much as 50 percent.

Starting in the 17th century, advances in science, medicine, agriculture and industry allowed rapid growth of human population and infanticide again became a common practice.

The next big influence on the human population occurred with the start of the Industrial rev - olution in the late 18th century. With the advent of factories, children became valuable labor resources, thereby contributing to survival, and family sizes increased. The resulting popula - tion boom was further aided by improvements in agricultural technology that led to increased food production. medical advancements increased control over disease and lengthened the average lifespan. By the early 19th century, the human population worldwide reached one billion. It was now in the stem of the J curve graph. As the world approached the 20th century, the human population was growing at an exponential rate.

During the 20th century, another important event in human population dynamics occurred.

The birth rates in the highly developed countries decreased dramatically. Factors contribut - ing to this decrease included: a rise in the standard of living, the availability of practical birth control methods and the establishment of child education and labor laws. These factors made large families economically impractical.

Figure 2.2: Human population growth throughout history The human population grew slowly at first, declined during the spread of the Black Death, and mushroomed beginning in the 17th century. Exponential population growth is represented by a J curve.

Based on data from U.S. Census Bureau. Retrieved from http://www.census.gov/population/international/data/worldpop /table_history.php and http://www.census.gov/population/international/data/worldpop/table_popul\ ation.php J Curve Human Population (billions) 0 1 3 2 4 5 6 7 8 4000BCE 2000 BCE 1250 CE 1400 CE 1600 CE 1650 CE 1850 CE 1930 1975 2002 2009 2 013 7 million 27 million 400 million 350 million545 million 470 million 1.1 billion 2 billion4 billion6.2 billion 6.7 billion 7 billion Year ben85927_02_c02.indd 69 1/20/14 2:32 PM SEcTIon 2.1 Po PuLATI on Gro WTH AnD DEmo GrAPHI cS Population Demographics Human demography (population change) is usually described in terms of the births and deaths per 1000 people. When births of an area exceed deaths, population increases. When the births of an area are fewer than deaths, the population decreases. The annual rate at which the size of a population changes is: natural Population change rate (%) 5 [(Births 2 Deaths)/1000] 3 100 During the year 2000, the birth rate for the world was 22 and the death rate was 9. Thus, the world’s population grew at a rate of 1.3 percent. The annual rate of population change for a particular city or region is also affected by immigration (movement of people into a region) and emigration (movement out of a region). Population change rate (%) 5 (Birth rate 1 Immigration rate) 2 (Death rate 1 Emigration rate) Highly industrialized nations, like the united States, canada, Japan, and Germany, generally have low birth and death rates. Annual rates of natural population change vary from 20.1% to 0.5%. In some industrial nations (e.g. Germany and russia) death rates exceed birth rates so the net population decreases over time. newly industrialized countries (e.g. South Korea, mexico and china) have moderate birth rates and low death rates. The low death rates result from better sanitation, better heath care and stable food production that accompany industrialization.

The annual rates of natural population change are about 1 percent to 2 percent in these coun - tries. countries with limited industrial development (e.g. Pakistan and Ethiopia) tend to have high birth rates and moderate to low death rates. These nations are growing rapidly with annual rates of natural population change exceeding 2 percent.

Several factors influence human fertility. Important factors influencing birth and fertility rates in human populations are: affluence, average marriage age, availability of birth control, family labor needs, cultural beliefs, religious beliefs, and the cost of raising and educating children.

The rapid growth of the world’s population over the past 100 years is mainly [sic] results from a decline in death rates. reasons for the drop in death rates include: better nutrition, fewer infant deaths, increased average life span and improvements in medical technology.

Demographic Transition As countries become developed and industrialized, they experience a movement from high population growth to low population growth. Both death and birth rates decline.

These countries usually move from rapid population growth, to slow growth, to zero growth and finally to a reduction in population. This shift in growth rate with development is called the “demographic transition.” Four distinct stages occur during the transition: pre-industrial, transitional, industrial and post-industrial.

During the pre-industrial stage, harsh living conditions result in a high birth rate and a high death rate. The population grows very slowly, if at all. The transitional stage begins shortly ben85927_02_c02.indd 70 1/20/14 2:32 PM SEcTIon 2.1 Po PuLATI on Gro WTH AnD DEmo GrAPHI cS after industrialization. During this phase, the death rate drops because of increased food pro- duction and better sanitation and health conditions, but, the birth rate remains high. There - fore, the population grows rapidly.

During the industrial stage, industrial- ization is well established in the coun- try. The birth rate drops and eventually approaches the death rate. couples in cities realize that children are expensive to raise and that having large families restrict [sic] their job opportunities. The post-industrial stage occurs when the birth rate declines even further to equal the death rate, thus population growth reaches zero. The birth rate may eventu- ally fall below the death rate, resulting in negative population growth. Figure 2.3: Demographic transition The four stages of demographic transition show the change in population growth that a country experiences over time as it develops and industrializes.

Adapted from http://moodle.ties.k12.mn.us/course/view.php?id=780 Consider This During the transitional stage of the demo- graphic transition death rates begin to drop but birth rates remain high. Why might changes in birth rates lag behind changes in death rates?

Births and deaths (per thousand per year) 10 20 30 40 Phase 1:

Pre-industrial Phase 2:

Transitional Phase 3:

Industrial Phase 4:

Post-industrial Total population Death rateBirth rate ben85927_02_c02.indd 71 1/20/14 2:32 PM SEcTIon 2.1 Po PuLATI on Gro WTH AnD DEmo GrAPHI cS The united States and most European countries have experienced this gradual transition over the past 150 years. The transition moves much faster for today’s developing countries. This is because improvements in preventive health and medical care in recent decades have dramati- cally reduced mortality—especially infant mortality—and increased life expectancy.

In a growing number of countries, couples are having fewer children than the two they need to “replace” themselves. However, even if the level of “replacement fertility ” were reached today, populations would continue to grow for several decades because of the large numbers of people now entering their reproductive years.

As a result of reduced fertility and mortality, there will be a gradual demographic shift in all countries over the next few decades towards an older population. In developed countries, the proportion of people over age 65 has increased from 8 to 14 percent since 1950, and is expected to reach 25 percent by 2050. Within the next 35 years, those over age 65 will rep- resent 30 percent or more of the populations in Japan and Germany. In some countries, the number of residents over age 85 will more than double.

Adapted from AP Environmental Science chapter 6—History and Global Distribution. In Encyclopedia of Earth.

Eds. Cutler J. Cleveland (Washington, D.C.: Environmental Information Coalition, National Council for Science and the Environment). [First published in the Encyclopedia of Earth November 25, 2008; last revised date November 25, 2008. Retrieved February 26, 2011, from http://www.eoearth.org/article/AP_Environmental_Science_ chapter _6-_History_and_Global_Distribution . Apply Your Knowledge using the following formula, calculate the population growth rates for the following three countries based on actual demographic data from 2013, shown in Table 2.1.

Formula: Population growth rate 5 [(birth rate 2 death rate)/1000] 3 100 Table 2.1: Demographic data for selected countries, 2013 Country Birth rateDeath rate uganda 45 11 malaysia 20 5 Germany 8 11 Source: Data compiled from central Intelligence Agency. The World Factbook. retrieved from https://www.cia .gov/library/publications/the-world-factbook/rankorder/2054rank.html and https://www.cia.gov/library /publications/the-world-factbook/rankorder/2066rank.html What stage of the demographic transition is each country in? What would you hypothesize are causing the sharp differences in birth rates between these countries? ben85927_02_c02.indd 72 1/20/14 2:32 PM SEcTIon 2.2 Fu Tur E Po PuLATI on Tr EnDS 2.2 Future Population Trends By the 1960s, human population growth was so rapid that fears of a “population bomb” and global famine became widespread. Of particular concern were high fertility rates and popula- tion growth in poorer countries of the Third World where women, on average, were often hav - ing seven or eight children each. Efforts were made in population policy around the world to reduce fertility rates through a variety of means, some more controversial than others. Today, most of these countries have moved through a demographic transition and have seen fertility rates decline to only two or three children per woman. According to the national Geographic article below, “Population 7 Billion,” by Robert Kunzig, demographers are now projecting that the human population could stabilize at 8 or 9 billion by 2050 or surge to as high as 11 billion by 2100. The actual number will depend on choices made by individual couples about how many children they will have.

The study of how human population has grown from the millions to billions presents something of a paradox. At a fundamental level, the exponential growth in human numbers over the past 200 years was triggered by humans living longer, healthier lives. Because fertility rates and birth rates at first stayed high while death rates dropped, human numbers grew. Longer lives and lower death rates are of course a good thing. However, the population growth that began with these changes is still adding close to 80 million new people to the planet each year (for com - parison, New York City’s population is approximately 8.4 million), even as fertility rates continue to drop around the world. The only way to stabilize population is for average fertility rates to reach approximately two children per woman. This figure is known as the replacement fertility rate because it represents the number of children needed to replace a set of parents.

Policy and program efforts to bring fertility rates down and “speed up” the demographic tran - sition have taken a variety of different forms. Some governments have used coercive means to reduce fertility or provided economic incentives such as better housing and jobs for couples with fewer children. Others have taken a more holistic view based on research that has shown that In Depth: Birth and Death Rates A very interesting way to see how you fit in to a global population of 7 billion is provided by the BB c. Go to this link, enter your date of birth, and see how many people were alive when you were born, how many people are born every hour, and what countries of the world are seeing the most rapid increases or decreases in population: http://www.bbc.co.uk/news /world-15391515 An interesting analogy for how birth rates and death rates combine to influence popula - tion is provided in this link. Births are compared to water dripping into a cup while deaths are likened to water dripping out of the cup. As long as the rate of water dripping into the cup is the same as the water dripping out, the water level in the cup—representing overall population—will stay the same: http://www.npr.org/2011/10/31/141816460 /visualizing-how-a-population-grows-to-7-billion ben85927_02_c02.indd 73 1/20/14 2:32 PM SEcTIon 2.2 Fu Tur E Po PuLATI on Tr EnDS women with better access to education, health care, and economic opportunities will tend to have fewer children even without coercion or explicit incentives. These differences in approach are examined in this article through examples from two regions of India. While this reading is cautiously optimistic about the prospects for population stabilization and the avoidance of an environmental catastrophe, it’s important to remember that it’s not just human numbers that determine environmental impact. Growing numbers of people combined with rising standards of living and rates of consumption have many environmental scientists concerned. The issue of resource consumption and the links between population, affluence, and technology will be explored in this and the next section.

By R. J. Kunzig Historians now estimate that in [Antoni van] Leeuwenhoek’s [considered to be the first micro- biologist] day [the 1670s] there were only half a billion or so humans on Earth. After rising very slowly for millennia, the number was just starting to take off. A century and a half later [. . .] the world’s population had doubled to more than a billion. A century after that, around 1930, it had doubled again to two billion. The acceleration since then has been astounding.

Before the 20th century, no human had lived through a doubling of the human population, but there are people alive today who have seen it triple. Sometime in late 2011, according to the un [united nations] Population Division, there will be seven billion of us [ no TE: this article was originally published in early 2011, before global population reached seven billion. That milestone is estimated to have occurred on october 30, 2011 with the birth of Danica may camacho in the Philippines. Today the global population is over 7.1 billion; you can check an updated estimate of global population here: http://www.census.gov/popclock ].

And the explosion, though it is slowing, is far from over. not only are people living longer, but so many women across the world are now in their childbearing years—1.8 billion—that the global population will keep growing for another few decades at least, even though each woman is having fewer children than she would have had a generation ago. By 2050 the total number could reach 10.5 billion, or it could stop at eight billion—the difference is about one child per woman. un demographers consider the middle road their best estimate: They now project that the population may reach nine billion before 2050—in 2045. The eventual tally will depend on the choices individual couples make. [. . .] With the population still growing by about 80 million each year, it’s hard not to be alarmed.

right now on Earth, water tables are falling, soil is eroding, glaciers are melting, and fish stocks are vanishing. close to a billion people go hungry each day. Decades from now, there will likely be two billion more mouths to feed, mostly in poor countries. There will be billions more people wanting and deserving to boost themselves out of poverty. If they follow the path blazed by wealthy countries—clearing forests, burning coal and oil, freely scattering fertil - izers and pesticides—they too will be stepping hard on the planet’s natural resources. How exactly is this going to work?

Early Warnings In 1798 Thomas malthus, an English priest and economist, enunciated his general law of pop - ulation: that it necessarily grows faster than the food supply, until war, disease, and famine arrive to reduce the number of people. As it turned out, the last plagues great enough to put a dent in global population had already happened when malthus wrote. World population hasn’t fallen, historians think, since the Black Death of the 14th century. ben85927_02_c02.indd 74 1/20/14 2:32 PM SEcTIon 2.2 Fu Tur E Po PuLATI on Tr EnDS In the two centuries after malthus declared that population couldn’t continue to soar, that’s exactly what it did. The process started in what we now call the developed countries, which were then still developing. The spread of new World crops like corn and the potato, along with the discovery of chemical fertilizers, helped banish starvation in Europe. Growing cities remained cesspools of disease at first, but from the mid-19th century on, sewers began to channel human waste away from drinking water, which was then filtered and chlorinated; that dramatically reduced the spread of cholera and typhus.

moreover in 1798, the same year that malthus published his dyspeptic [troubling] tract, his compatriot Edward Jenner described a vaccine for smallpox—the first and most impor- tant in a series of vaccines and antibiotics that, along with better nutrition and sanita - tion, would double life expectancy in the industrializing countries, from 35 years to 77 today. It would take a cranky per - son to see that trend as gloomy: “The development of medical science was the straw that broke the camel’s back,” wrote Stanford population biologist Paul Ehrlich in 1968.

Ehrlich’s book, The Population Bomb, made him the most famous of modern malthu - sians. In the 1970s, Ehrlich predicted, “hundreds of millions of people are going to starve to death,” and it was too late to do anything about it. “The cancer of popula - tion growth [. . .] must be cut out,” Ehrlich wrote, “by compulsion if voluntary meth- ods fail.” The very future of the united States was at risk. In spite or perhaps because of such language, the book was a best seller, as malthus’s had been. And this time too the bomb proved a dud. The green revolution—a combi - nation of high-yield seeds, irrigation, pesticides, and fertilizers that enabled grain production to double—was already under way. Today many people are undernourished, but mass starva - tion is rare. Changes in Birth and Death Rates Ehrlich was right, though, that population would surge as medical science spared many lives.

After World War II the developing countries got a sudden transfusion of preventive care, with the help of institutions like the World Health organization and un IcEF. Penicillin, the small - pox vaccine, DDT (which, though later controversial, saved millions from dying of malaria)— all arrived at once. In India life expectancy went from 38 years in 1952 to 64 today; in china, from 41 to 73. millions of people in developing countries who would have died in childhood survived to have children themselves. That’s why the population explosion spread around the planet: because a great many people were saved from dying.

And because, for a time, women kept giving birth at a high rate. In 18th-century Europe or early 20th-century Asia, when the average woman had six children, she was doing what it took to replace herself and her mate, because most of those children never reached adulthood. When child mortality declines, couples eventually have fewer children—but that transition usually Consider This First Thomas malthus in 1798 and then Paul Ehrlich in 1968 wrote about impend- ing famine and starvation due to popu- lation growth. Both predictions did not come to pass. Does this mean that popu- lation growth and overpopulation are not really a problem? What might have pre- vented these forecasts from coming true, and can we expect the same to happen in the future? ben85927_02_c02.indd 75 1/20/14 2:32 PM SEcTIon 2.2 Fu Tur E Po PuLATI on Tr EnDS Apply Your Knowledge china’s approach to population policy is among the most recognized and controversial in the world. With a 2013 population of over 1.3 billion people (19 percent of the world total), china is the most populous nation on the planet. However, it’s possible that in the absence of aggres- sive efforts to reduce fertility and birth rates china’s population today would have been over two billion. china instituted a one-child-per-family rule in 1979. Families complying with this policy received rewards in the form of better access to health care, education, housing, and employment. Families that violated this policy were not eligible for these benefits and even faced monetary fines. china’s population policy has been criticized on human rights grounds. (continued) takes a generation at the very least. Today in developed countries, an average of 2.1 births per woman would maintain a steady population; in the developing world, “replacement fertility” is somewhat higher. In the time it takes for the birthrate to settle into that new balance with the death rate, population explodes.

Demographers call this evolution the demographic transition. All countries go through it in their own time. It’s a hallmark of human progress: In a country that has completed the transi- tion, people have wrested from nature at least some control over death and birth. The global population explosion is an inevitable side effect, a huge one that some people are not sure our civilization can survive. But the growth rate was actually at its peak just as Ehrlich was sounding his alarm. By the early 1970s, fertility rates around the world had begun dropping faster than anyone had anticipated. Since then, the population growth rate has fallen by more than 40 percent.

The Fertility Transition In industrialized countries it took generations for fertility to fall to the replacement level or below. As that same transition takes place in the rest of the world, what has astonished demographers is how much faster it is happening there. Though its population continues to grow, china, home to a fifth of the world’s people, is already below replacement fertility and has been for nearly 20 years, thanks in part to the coercive one-child policy implemented in 1979; chinese women, who were bearing an average of six children each as recently as 1965, are now having around 1.5. In Iran, with the support of the Islamic regime, fertility has fallen more than 70 percent since the early ‘80s. In catholic and democratic Brazil, women have reduced their fertility rate by half over the same quarter century. “We still don’t understand why fertility has gone down so fast in so many societies, so many cultures and religions. It’s just mind-boggling,” says Hania Zlotnik, director of the un Population Division. “At this moment, much as I want to say there’s still a problem of high fertility rates, it’s only about 16 percent of the world population, mostly in Africa,” says Zlotnik. South of the Sahara, fertility is still five children per woman; in niger it is seven. But then, 17 of the countries in the region still have life expectancies of 50 or less; they have just begun the demographic transi- tion. In most of the world, however, family size has shrunk dramatically. The un projects that the world will reach replacement fertility by 2030. “The population as a whole is on a path toward nonexplosion—which is good news,” Zlotnik says. ben85927_02_c02.indd 76 1/20/14 2:32 PM SEcTIon 2.2 Fu Tur E Po PuLATI on Tr EnDS The bad news is that 2030 is two decades away and that the largest generation of adolescents in history will then be entering their childbearing years. Even if each of those women has only two children, population will coast upward under its own momentum for another quarter century. [. . .] The Case of India The Indian government tried once before to push vasectomies, in the 1970s, when anxiety about the population bomb was at its height. Prime minister Indira Gandhi and her son Sanjay used state-of-emergency powers to force a dramatic increase in sterilizations. From 1976 to 1977 the number of operations tripled, to more than eight million. over six million of those were vasectomies. Family planning workers were pressured to meet quotas; in a few states, sterilization became a condition for receiving new housing or other government benefits. In some cases the police simply rounded up poor people and hauled them to sterilization camps.

The excesses gave the whole concept of family planning a bad name. “Successive governments refused to touch the subject,” says Shailaja chandra, former head of the national Population Stabilisation Fund ( nPSF). Yet fertility in India has dropped anyway, though not as fast as in china, where it was nose-diving even before the draconian [unusually severe] one-child policy took effect. The national average in India is now 2.6 children per woman, less than half what it was when Ehrlich visited [in 1966]. The southern half of the country and a few states in the northern half are already at replacement fertility or below.

In Kerala, on the southwest coast, investments in health and education helped fertility fall to 1.7. The key, demographers there say, is the female literacy rate: At around 90 percent, it’s easily the highest in India. Girls who go to school start having children later than ones who don’t. They are more open to contraception and more likely to understand their options.

So far this approach, held up as a model internationally, has not caught on in the poor states of northern India—in the “Hindi belt” that stretches across the country just south of Delhi.

nearly half of India’s population growth is occurring in rajasthan, madhya Pradesh, Bihar, and uttar Pradesh, where fertility rates still hover between three and four children per woman.

more than half the women in the Hindi belt are illiterate, and many marry well before reach - ing the legal age of 18. They gain social status by bearing children—and usually don’t stop until they have at least one son. Apply Your Knowledge (continued) In its early years overzealous enforcement of the rules led to forced abortions and sterilizations.

A strong cultural preference for sons has also resulted in high rates of selective abortions of female fetuses and female babies being given up for adoption. As a result, china has one of the most skewed male-female sex ratios in the world, with roughly 120 boys for every 100 girls.

Despite these criticisms, it could be argued that china needed to take aggressive action to slow the growth of its population, especially after suffering through horrendous famines that killed millions of people in the 1960s. What do you think? Do the “ends” (fertility rates in china have dropped from over 5 in 1970 to under 2 today) justify the “means” in this case? could china have used other, less coercive means to achieve its population policy goals? ben85927_02_c02.indd 77 1/20/14 2:32 PM SEcTIon 2.2 Fu Tur E Po PuLATI on Tr EnDS The Andhra Pradesh Model As an alternative to the Kerala model, some point to the southern state of Andhra Pradesh, where sterilization “camps”—temporary operating rooms often set up in schools—were introduced during the ‘70s and where sterilization rates have remained high as improved hos- pitals have replaced the camps. In a single decade beginning in the early 1990s, the fertility rate fell from around three to less than two. unlike in Kerala, half of all women in Andhra Pradesh remain illiterate.

Amarjit Singh, the current executive director of the nPSF, calculates that if the four biggest states of the Hindi belt had followed the Andhra Pradesh model, they would have avoided 40 million births—and considerable suf- fering. “Because 40 million were born, 2.5 million children died,” Singh says.

He thinks if all India were to adopt high-quality programs to encourage sterilizations, in hospitals rather than camps, it could have 1.4 billion people in 2050 instead of 1.6 billion.

critics of the Andhra Pradesh model, such as the Population Foundation’s [A. r.] nanda, say Indians need better health care, particularly in rural areas.

They are against numerical targets that pressure government workers to sterilize people or cash incentives that distort a couple’s choice of family size. “It’s a private decision,” nanda says. In Indian cities today, many couples are making the same choice as their coun- terparts in Europe or America. Sonalde Desai, a senior fellow at new Delhi’s national council of Applied Economic research, introduced me to five work - ing women in Delhi who were spending most of their salaries on private-school fees and after-school tutors; each had one or two children and was not plan - ning to have more. In a nationwide sur - vey of 41,554 households, Desai’s team identified a small but growing vanguard of urban one-child families. “We were totally blown away at the emphasis par - ents were placing on their children,” she says. “It suddenly makes you understand—that is why fertility is going down.” Indian children on average are much better educated than their parents. AP Photo/Mustafa Quraishi Women check in at a free sterilization clinic at the Mohan Lal Gautam District Women’s Hospital in Aligarh, India. Every day dozens of women line up at this hospital for a free sterilization procedure. Consider This A. r. nanda, former head of the Population Foundation of India, is cited here as saying that the choice of family size is “a private decision.” Some people argue that the dan- gers of overpopulation are so great that decisions about family size should not be a strictly private decision. What’s your view of this matter? ben85927_02_c02.indd 78 1/20/14 2:32 PM SEcTIon 2.2 Fu Tur E Po PuLATI on Tr EnDS That’s less true in the countryside. With Desai’s team I went to Palanpur, a village in uttar Pradesh—a Hindi-belt state with as many people as Brazil. Walking into the village we passed a cell phone tower but also rivulets of raw sewage running along the lanes of small brick houses. under a mango tree, the keeper of the grove said he saw no reason to educate his three daughters. under a neem tree in the center of the village, I asked a dozen farmers what would improve their lives most. “If we could get a little money, that would be wonder- ful,” one joked.

The Demographer’s Perspective The annual meeting of the Population Association of America (PAA) is one of the premier gatherings of the world’s demographers. Last April [2010] the global population explosion was not on the agenda. “The problem has become a bit passé,” Hervé Le Bras [a French demog - rapher] says. Demographers are generally confident that by the second half of this century we will be ending one unique era in history—the population explosion—and entering another, in which population will level out or even fall.

But will there be too many of us? At the PAA meeting, in the Dallas Hyatt regency, I learned that the current population of the planet could fit into the state of Texas, if Texas were settled as densely as new York city. The comparison made me start thinking like Leeuwenhoek. If in 2045 there are nine billion people living on the six habitable continents, the world population density will be a little more than half that of France today. France is not usually considered a hellish place. Will the world be hellish then?

Some parts of it may well be; some parts of it are hellish today. There are now 21 cities with populations larger than ten million, and by 2050 there will be many more. Delhi adds hun- dreds of thousands of migrants each year, and those people arrive to find that “no plans have been made for water, sewage, or habitation,” says Shailaja chandra. Dhaka in Bangladesh and Kinshasa in the Democratic republic of the congo are 40 times larger today than they were in 1950. Their slums are filled with desperately poor people who have fled worse poverty in the countryside.

many people are justifiably worried that malthus will finally be proved right on a global scale—that the planet won’t be able to feed nine billion people. Lester Brown, founder of Worldwatch Institute and now head of the Earth Policy Institute in Washington, believes food shortages could cause a collapse of global civilization. Human beings are living off natural capital, Brown argues, eroding soil and depleting groundwater faster than they can be replen - ished. All of that will soon be cramping food production. Brown’s Plan B to save civilization would put the whole world on a wartime footing, like the u.S. after Pearl Harbor, to stabilize climate and repair the ecological damage. “Filling the family planning gap may be the most urgent item on the global agenda,” he writes, so if we don’t hold the world’s population to eight billion by reducing fertility, the death rate may increase instead.

Eight billion corresponds to the un ’s lowest projection for 2050. In that optimistic sce - nario, Bangladesh has a fertility rate of 1.35 in 2050, but it still has 25 million more people than it does today. rwanda’s fertility rate also falls below the replacement level, but its population still rises to well over twice what it was before the genocide [1994 mass killing of Tutsis and moderate Hutus]. If that’s the optimistic scenario, one might argue, the future is indeed bleak. ben85927_02_c02.indd 79 1/20/14 2:32 PM SEcTIon 2.2 Fu Tur E Po PuLATI on Tr EnDS Hope for the Future?

But one can also draw a different conclusion—that fixating on population numbers is not the best way to confront the future. People packed into slums need help, but the problem that needs solving is poverty and lack of infrastructure, not overpopulation. Giving every woman access to family planning services is a good idea—”the one strategy that can make the biggest difference to women’s lives,” chandra calls it. But the most aggressive population control pro - gram imaginable will not save Bangladesh from sea level rise, rwanda from another genocide, or all of us from our enormous environmental problems.

Global warming is a good example. carbon emissions from fossil fuels are growing fastest in china, thanks to its prolonged economic boom, but fertility there is already below replace - ment; not much more can be done to control population. Where population is growing fastest, in sub-Saharan Africa, emissions per person are only a few percent of what they are in the u.S.—so population control would have little effect on climate. Brian o’neill of the national center for Atmospheric research has calculated that if the population were to reach 7.4 bil - lion in 2050 instead of 8.9 billion, it would reduce emissions by 15 percent. “Those who say the whole problem is population are wrong,” Joel cohen [Professor of Populations and head of the Laboratory of Populations at the rockefeller university and columbia university] says. “It’s not even the dominant factor.” To stop global warming we’ll have to switch from fossil fuels to alternative energy—regardless of how big the population gets.

The number of people does matter, of course. But how people consume resources matters a lot more. Some of us leave much bigger footprints than others. The central challenge for the future of people and the planet is how to raise more of us out of poverty—the slum dwellers in Delhi, the subsistence farmers in rwanda—while reducing the impact each of us has on the planet.

The World Bank has predicted that by 2030 more than a billion people in the developing world will belong to the “global middle class,” up from just 400 million in 2005. That’s a good thing. But it will be a hard thing for the planet if those people are eating meat and driving gasoline-powered cars at the same rate as Americans now do. It’s too late to keep the new middle class of 2030 from being born; it’s not too late to change how they and the rest of us will produce and consume food and energy. “Eating less meat seems more reasonable to me than saying, ‘Have fewer children!’” Le Bras says.

How many people can the Earth support? cohen spent years reviewing all the research, from Leeuwenhoek on. “I wrote the book thinking I would answer the question,” he says. “I found out it’s unanswerable in the present state of knowledge.” What he found instead was an enor- mous range of “political numbers, intended to persuade people” one way or the other.

Conclusion For centuries population pessimists have hurled apocalyptic warnings at the congenital opti- mists, who believe in their bones that humanity will find ways to cope and even improve its lot. History, on the whole, has so far favored the optimists, but history is no certain guide to the future. neither is science. It cannot predict the outcome of People v. Planet, because all the facts of the case—how many of us there will be and how we will live—depend on choices we have yet to make and ideas we have yet to have. We may, for example, says cohen, “see to it that all children are nourished well enough to learn in school and are educated well enough to solve the problems they will face as adults.” That would change the future significantly. ben85927_02_c02.indd 80 1/20/14 2:32 PM SEcTIon 2.3 Po PuLATI on Gro WTH , mATE rIAL con Sum PTI on, AnD THE I PAT Equ ATI on The debate was present at the creation of population alarmism, in the person of rev. Thomas malthus himself. Toward the end of the book in which he formulated the iron law by which unchecked population growth leads to famine, he declared that law a good thing: It gets us off our duffs. It leads us to conquer the world. man, malthus wrote, and he must have meant woman too, is “inert, sluggish, and averse from labour, unless compelled by necessity.” But necessity, he added, gives hope:

“The exertions that men find it necessary to make, in order to support themselves or families, frequently awaken faculties that might otherwise have lain for ever dormant, and it has been commonly remarked that new and extraordinary situations generally create minds adequate to grapple with the difficulties in which they are involved.” Seven billion of us soon, nine billion in 2045. Let’s hope that malthus was right about our ingenuity.

Adapted from Kunzig, R. J. (2011, January). Population 7 Billion. national Geographic. Retrieved from http://ngm .nationalgeographic.com/2011/01/seven-billion/kunzig-text . Kunzig, Robert J./National Geographic Creative.

Used by permission. 2.3 Population Growth, Material Consumption, and the I PAT Equation As mentioned in the previous essay, as a general rule, a larger human population means a greater environmental impact on our planet. Indeed, more people create an increased demand for food, fuel, water, and minerals, all of which cause some environmental impact during their produc - tion. However, demographers and environmental scientists realize that the impact a population has on the environment is determined not just by the number of people involved but by the kinds of technologies used and their relative levels of affluence and material consumption. This has led to the development of a formula known as I 5 PAT to study the environmental impact of the different variables, as explained in this article by Paul R. and Anne H. Ehrlich.

The I 5 PAT equation expresses the idea that the environmental impact (I) of a given population will be determined by the interactions of the size of that population (P), the average affluence or consumption rate of individuals in that population (A), and the kinds of technologies that popu - lation makes use of (T). In recent decades most ecologists and environmental scientists have fixated on the P factor, population, as human numbers have grown from less than two billion in 1900 to over seven billion today. However, with population growth rates beginning to slow and global population possibly stabilizing at nine or ten billion later this century, more attention is being paid to the A and T factors—how much we consume and what technologies we use to enable that consumption.

The I 5 PAT concept is sometimes expressed through the idea of an ecological footprint—a mea - sure of how much land and water is required to support the consumption of an individual. You might live in a small apartment in the city, but your lifestyle requires forestland for the produc - tion of paper and farmland for the production of food (among other things), and so your actual footprint will be larger than the space you occupy. While concerns over growing populations have focused on the poorer developing countries of the world, I 5 PAT and footprint analysis have shown that high consumption rates in more wealthy developed countries also result in significant environmental impacts. However, as this provocative article argues, any discussion of “appropriate” or “sustainable” rates of consumption can be controversial. Bringing up issues of 5 5 ben85927_02_c02.indd 81 1/20/14 2:32 PM SEcTIon 2.3 Po PuLATI on Gro WTH , mATE rIAL con Sum PTI on, AnD THE I PAT Equ ATI on who gets to consume how much of what is no easy task. As you read this article focus on the key concept of how population, rates of consumption, and technology combine to determine overall environmental impact.

By P. R. and A. H. Ehrlich over some 60 million years, Homo sapiens has evolved into the dominant animal on the planet, acquiring binocular vision, upright posture, large brains, and—most importantly—language with syntax and that complex store of non-genetic information we call culture. However, in the last several centuries we’ve increasingly been using our relatively newly acquired power, espe - cially our culturally evolved technologies, to deplete the natural capital of Earth—in particular its deep, rich agricultural soils, its groundwater stored during ice ages, and its biodiversity—as if there were no tomorrow.

The point, all too often ignored, is that this trend is being driven in large part by a combination of population growth and increasing per capita consumption, and it cannot be long continued without risking a collapse of our now-global civilization. Too many people—and especially too many politicians and business executives—are under the delusion that such a disastrous end to the modern human enterprise can be avoided by technological fixes that will allow the population and the economy to grow forever. But if we fail to bring population growth and over-consumption under control the number of people on Earth is expected to grow from 6.5 billion today [2008] to 9 billion by the second half of the 21st century—then we will inhabit a planet where life becomes increasingly untenable because of two looming crises: global heat - ing, and the degradation of the natural systems on which we all depend. I 5 PAT our species’ negative impact on our own life-support systems can be approximated by the equation I 5 PAT . In that equation, the size of the population (P) is multiplied by the average affluence or consumption per individual (A), and that in turn is multiplied by some measure of the technology (T) that services and drives the consumption. Thus commuting in automo - biles powered by subsidized fossil fuels on proliferating freeways creates a much greater T factor than commuting on bikes using simple paths or working at home on a computer network. The product of P, A, and T is Impact (I), a rough estimate of how much humanity is degrading the ecosystem services it depends upon.

The equation is not rocket science. Two billion people, all else being equal, put more greenhouse gases into the atmo- sphere than one billion people. Two bil- lion rich people disrupt the climate more than two billion poor people. Three hun- dred million Americans consume more petroleum than 1.3 billion chinese. And Consider This The I 5 PAT formula is imagined as being multiplicative—that is, environmental impact (I) is a product of P (population) 3 A (affluence) 3 T (technology). Imagine a simple representation of this where P, A, and T are all equal to 10 units: I 5 10 3 10 3 10, or 1,000. What happens to environ- mental impact if population doubles and everything else stays the same? What if population stays the same, affluence dou- bles, and technology is cut in half ?

5 ben85927_02_c02.indd 82 1/20/14 2:32 PM SEcTIon 2.3 Po PuLATI on Gro WTH , mATE rIAL con Sum PTI on, AnD THE I PAT Equ ATI on driving an S uV is using a far more environmentally malign transportation technology than riding mass transit.

The technological dimensions of our predicament—such as the need for alternatives to fos- sil fuel energy—are frequently discussed if too little acted upon. Judging from media reports and the statements of politicians, environmental problems, to the degree they are recognized, can be solved by minor changes in technologies and recycling (T). Switching to ultra-light, fuel-efficient cars will obviously give some short-term advantage, but as population and consumption grow, they will pour still more carbon dioxide (and vaporized rubber) into the atmosphere and require more natural areas to be buried under concrete. more recycling will help, but many of our society’s potentially most dangerous effluents [pollutants that flow out into the environment] (such as hormone-mimicking chemicals) cannot practically be recy - cled. There is no technological change we can make that will permit growth in either human numbers or material affluence to continue to expand. In the face of this, the neglect of the intertwined issues of population and consumption is stunning.

Population many past human societies have collapsed under the weight of overpopulation and envi - ronmental neglect, but today the civilization in peril is global. The population factor in what appears to be a looming catastrophe is even greater than most people suppose. Each person added today to the population on average causes more damage to humanity’s critical life- support systems than did the previous addition—everything else being equal. The reason is simple: Homo sapiens became the dominant animal by being smart. Farmers didn’t settle first on poor soils where water was scarce, but rather in rich river valleys. That’s where most cities developed, where rich soils are now being paved over for roads and suburbs, and where water supplies are being polluted or overexploited.

As a result, to support additional people it is nec - essary to move to ever poorer lands, drill wells deeper, or tap increasingly remote sources to obtain water—and then spend more energy to transport that water ever greater distances to farm fields, homes, and factories. our distant ancestors could pick up nearly pure copper on Earth’s surface when they started to use metals; now people must use vast amounts of energy to mine and refine gigantic amounts of copper ore of ever poorer quality, some in concentrations of less than one percent. The same can be said for other important metals. And petroleum can no longer be found easily on or near the surface, but must be gleaned from wells drilled a mile or more deep, often in inaccessible localities, such as under continental shelves beneath the sea.

All of the paving, drilling, fertilizer manufacturing, pumping, smelting, and transporting needed to Eye Ubiquitous/SuperStock The search for resources for a growing global population has moved into less wealthy nations. This gold mine is located in the west African country of Ghana. 5 ben85927_02_c02.indd 83 1/20/14 2:32 PM SEcTIon 2.3 Po PuLATI on Gro WTH , mATE rIAL con Sum PTI on, AnD THE I PAT Equ ATI on provide for the consumption of burgeoning numbers of people produces greenhouse gases and thus tightens the connection between population and climate disruption.

Affluence and Technology Silence on the overconsumption (Affluence) factor in the I 5 PAT equation is more readily explained. consumption is still viewed as an unalloyed [pure] good by many economists, along with business leaders and politicians, who tend to see jacking up consumption as a cure-all for economic ills. Too much unemployment? Encourage people to buy an S uV or a new refrigerator. Perpetual growth is the creed of the cancer cell, but third-rate economists can’t think of anything else. Some leading economists are starting to tackle the issue of over- consumption, but the problem and its cures are tough to analyze. [. . .] And, of course, there are the vexing problems of consumption of people in poor countries. on one hand, a billion or more people have problems of underconsumption . unless their basic needs are met, they are unlikely to be able to make important contributions to attaining sus - tainability. on the other hand, there is also the issue of the “new consumers” in developing economies such as china and India, where the wealth of a sizable minority is permitting them to acquire the consumption habits (e.g., eating a lot of meat and driving automobiles) of the rich nations. consumption regulation is a lot more complex than population regulation, and it is much more difficult to find humane and equitable solutions to the problem.

The dominant animal is wasting its bril- liance and its wonderful achievements; civilization’s fate is being determined by decision makers who determinedly look the other way in favor of immediate com- fort and profit. Thousands of scientists recently participated in a millennium Ecosystem Assessment that outlined our current environmental dilemma, but the report’s dire message made very little impact. Absent attention to that message, the fates of Easter Island, the classic maya civilization, and nineveh—all of which collapsed following environmental degradation—await us all.

We believe it is possible to avoid that global denouement [outcome]. Such mobilization means developing some consensus on goals—perhaps through a global dialogue in which people discuss the human predicament and decide whether they would like to see a maximum num - ber of people living at a minimum standard of living, or perhaps a much lower population size that gives individuals a broad choice of lifestyles. We have suggested a forum for such a dialogue, modeled partly on the Intergovernmental Panel on climate change [intergovern - mental body that studies and reports scientific findings on global climate change], but with more “bottom up” participation. It is clear that only widespread changes in norms can give humanity a chance of attaining a sustainable and reasonably conflict-free society.

How to achieve such change—involving everything from demographic policies and trans - formation of planet-wide energy, industrial, and agricultural systems, to north-South and Consider This Why might “consumption regulation” be a lot more complex than population regulation? 5 ben85927_02_c02.indd 84 1/20/14 2:32 PM SEcTIon 2.3 Po PuLATI on Gro WTH , mATE rIAL con Sum PTI on, AnD THE I PAT Equ ATI on Apply Your Knowledge Another way to express the idea that affluence and technology help determine environmental impact, not just population, is through the use of ecological footprint analysis. An ecological footprint is a measure of how much land and water area is necessary to support an individual or group of people. A poor farmer in India is almost certainly using fewer resources to support her family than a wealthy individual in a country like the u.S., and she therefore has a smaller ecological footprint. The idea of the ecological footprint is not to make people feel guilty about their lifestyles but to help them realize how their actions and decisions have an impact on the environment.

There are a number of ecological footprint calculators on the web that allow you to measure your own footprint. one of the best can be found here: http://www.myfootprint.org/ Visit this site and work your way step-by-step through the survey. You’ll be asked about the kind of house you live in, how much you drive, whether you make an effort to save water or energy, and what kinds of food you usually eat. At the end of the survey you’ll be shown a series of results, including:

The number of Planet Earths it would take to support 7 billion people if everyone lived like you; The number of acres of land it takes to support your lifestyle; The different biomes needed to support your lifestyle.

You’ll also be given a chance to read about how you can reduce your footprint. After read- ing that, go back and re-take the survey, this time adjusting your entries to reflect possible changes you could make (e.g., driving less, turning down the thermostat). What impact did these adjustments have on your total footprint and your other results? interfaith relationships and military postures—is a gigantic challenge to everyone. Politi - cians, industrialists, ecologists, social scientists, everyday citizens, and the media must join this debate. Whether it is possible remains to be seen; societies have managed to make major transitions in the recent past, as the civil rights revolution in the united States and the col - lapse of communism in the Soviet union clearly demonstrate. We’ll continue to hope and work for a cultural transformation in how we treat each other and the natural systems we depend upon. We can create a peaceful and sustainable global civiliza- tion, but it will require realistic thinking about the problems we face and a new mobilization of political will.

Adapted from Ehrlich, P. R. & Ehrlich, A. H. (2008). Too Many People, Too Much Consumption. Yale Environment 360. Copyright © 2008 Ehrlich, P. R. and A. H. Ehrlich. Retreived from http://e360.yale.edu/feature/too_many _people_too_much_consumption/2041/ . Reprinted by permission of the authors.5 ben85927_02_c02.indd 85 1/20/14 2:32 PM SEcTIon 2.4 Case History—Family Planning in Banglades H 2.4 Case History—Family Planning in Bangladesh Bangladesh is one of the poorest and most densely populated countries in the world. Yet, as the following case study “Reducing Fertility in Bangladesh,” by the Center for Global Development points out, this Asian nation has achieved rapid success in reducing fertility rates and getting its population growth rate under control. This was achieved through a family planning program that emphasized contraceptive availability and education throughout the country. In addition, emphasis has been placed on increasing educational and livelihood opportunities for women since research shows that both result in lower fertility rates.

What makes the success of the family planning effort in Bangladesh so interesting is that it did not rely on the coercion of individuals to have fewer children or the promise of economic incentives to encourage couples to have smaller families (as was the case in China). Instead, the program relied primarily on the efforts of thousands of family welfare assistants (mostly young women) who worked in rural villages throughout the country. They provided a wide range of family planning options to women as well as education on how to implement them.

That family planning efforts represented just one reason that the fertility rates dropped from 6.3 births per woman in the 1970s to only 3 births per woman in 2004 is equally interesting.

The other important factor was a change in social conditions in Bangladesh during this time.

The changes included significant increases in the number of girls and women enrolled in school, improved economic opportunities for women, and changes in cultural beliefs that resulted in greater empowerment for women overall. These two approaches—meeting unmet demand for family planning services and improving the status of women in society—offer perhaps the most effective and humane way to help societies complete the demographic transition and bring their populations under control. For that reason the case of Bangladesh is worthwhile to consider in a chapter on human population.

By the Center for Global Development of all the possible settings for success in family planning, Bangladesh would not be the first place to come to mind. It is the ninth most populous country in the world, with a per capita income of about $250 per year in the mid-1990s and close to 80 percent of the population living in poverty. Population density in Bangladesh is among the highest in the world, at more than 2,000 persons per square mile. The economy is primarily agricultural and faces increas- ing population pressure, with ever-increasing use of marginal lands; the per hectare agricul - tural yield is among the lowest in the world.

Given low levels of education—more than half of all Bangladeshi women are illiterate—and cultural traditions among both Hindu and muslim populations, which favor large families, high fertility would be expected. It is not surprising, then, that in the mid-1970s the average Bangladeshi woman was bearing about seven children during her lifetime, and the annual rate of population growth reached almost 2.5 percent. ben85927_02_c02.indd 86 1/20/14 2:32 PM SEcTIon 2.4 Case History—Family Planning in Banglades H A Program Motivated by Demographic Goals, Tempered by Experience The history of successful family planning in Bangladesh started with resounding failure. In the early 1960s, when Bangladesh was an eastern province of Pakistan—the result of the 1947 partition of India—the Pakistani government instituted a heavy-handed family plan- ning program that went against local needs and preferences. The coercive approaches used eventually led to a popular backlash, contributing to the 1968 collapse of the government. It was not until 1975, after a deadly famine and growing concerns about the demographic pres- sure on the country’s natural resources and economic prospects, that the now-independent Bangladesh embarked on a renewed family planning program. As it did so, leaders recalled the cautionary tale of how attempts to affect the most profound decisions in families and communities led to political conflict.

The main challenges facing the program at the start, in 1975, were low levels of knowledge about family planning, a prevailing belief that large families were best (typical of agrarian societies), low levels of women’s status, and lack of access to family planning services among the predominantly rural population—particularly among women who had limited mobility.

Each of these constraints was addressed through the program and through complementary public sector actions.

While the program evolved substantially over time with the application of operations research [. . .], in general it was characterized by four elements:

• The deployment of young, married women as outreach workers • The provision of as wide a range of methods as possible to meet a range of reproduc- tive needs • The establishment of family planning clinics in rural areas to provide clinical contra- ceptive services • The provision of information, education, and communication activities Young, married women were deployed as outreach workers and trained to conduct home visits with women, offering contraceptive services and information. The number of these outreach workers, referred to as fam - ily welfare assistants (FWAs), even - tually reached about 25,000 in the public sector; another 12,000 field workers were from nongovernmental organizations ( nGos). An additional 4,500 male outreach workers also were recruited.

Each FWA was expected to cover an area corresponding to three to five vil - lages, visiting each household once every two months. This way, each FWA could serve about 850 rural women. AP Photo/Pavel Rahman Family planning programs are gaining momentum in Bangladesh. Here, a public health worker explains the use of contraception to village women. ben85927_02_c02.indd 87 1/20/14 2:32 PM SEcTIon 2.4 Case History—Family Planning in Banglades H The reach of the program was staggering: Virtually all Bangladeshi women were contacted at least once by an FWA, and more than one third were reached at home every six months. The FWAs were well recognized village visitors and constituted the main link between the govern- ment program and rural women.

This type of outreach was seen as particu- larly important in the Bangladesh setting, where cultural practices (the tradition of purdah) restrict women’s mobility. Even where purdah was not strictly enforced, geographic isolation and difficult trans - port limited women’s ability to go to fixed sites for services.

The second element of the program was the provision of as wide a range of meth- ods as possible to meet a range of reproductive needs. With this “cafeteria approach,” the program offered a range of temporary methods as well as sterilization services for individu- als with two living children, where the youngest child was at least 2 years old. To support the work of the outreach workers, family planning commodities were provided through a well- managed distribution system.

The third element of the program was the family planning clinics established in rural areas to provide clinical contraceptive services, to which outreach workers could refer clients who wished to use long-term or permanent methods such as sterilization. Eventually, about 4,000 government facilities and 200 nongovernment clinics were established. ( nongovernmental organizations cover something on the order of one fifth of family planning clients.) In the early days of the program, most of the clinics were dedicated only to the provision of family planning services. more recently, efforts have been made to develop an integrated approach, where health workers provide both family planning and basic maternal and child health services, such as immunization services.

The fourth element was the information, education, and communication activities that were intended to change norms about family size and provide information about contraceptive options. In particular, state-of-the-art use of mass media proved to be effective. [. . .] Major Program Impact, Facilitated by Social Change Bangladesh’s family planning program demonstrated success in reaching its objectives of informing couples about contraceptive options, increasing the use of contraception, and decreasing fertility rates.

By 1991, when a contraceptive prevalence survey was conducted, almost all Bangladeshi women had some knowledge of modern contraception. Between 1975 and 1997, the pro- portion of married women who had ever used contraception increased fivefold, from about 14 percent to nearly 70 percent. The current use of contraception (also known as the con- traceptive prevalence rate, or cPr) increased by more than six times, from around 8 percent to 49 percent. In relative terms, the use of modern methods increased and traditional meth- ods decreased. With the wider availability of a range of methods, the use of sterilization and Consider This What were some of the cultural consider - ations that had to be addressed in design- ing a family planning program for rural areas of Bangladesh? ben85927_02_c02.indd 88 1/20/14 2:32 PM SEcTIon 2.4 Case History—Family Planning in Banglades H other long-acting methods declined, while the use of oral contraceptives and other temporary methods increased.

The provision of a wide range of contraceptive methods was shown to be an important influ- ence on the increase in overall use of contraceptives. The experience of the matlab evaluation showed that when a full range of methods was made available, 80 percent of women contin- ued using contraception for more than one year, while when only condoms and oral contra- ceptives were available, only 40 percent of women sustained use.

most important, fertility declined—from 6.3 births per woman in the early 1970s to about three births per woman in 2004. The greatest decline in fertility rates was observed among women aged 35 years and older. With this change, Bangladesh became one of few poor coun - tries to achieve major fertility declines without draconian measures, such as china’s one- child policy.

The Matlab Contribution Throughout the evolution of the Bangladesh family planning program, planners and program implementers, as well as donors, have benefited from the existence of the matlab Health research center, which has operated for more than 35 years as a site for large-scale opera - tions research on health programs. The matlab center has maintained decades worth of demo - graphic surveillance data on all births and deaths for a rural population of more than 220,000 people in about 142 villages in Bangladesh. Within the matlab villages, researchers have tested various approaches to delivery of reproductive, child, and other health services, using rigorous methods for field tests—and then been able to closely monitor the results through high-quality information systems. The knowledge generated through the matlab evaluations has been instrumental in shaping both Bangladesh’s health programs and maternal and child health programs throughout the developing world. In fact, much of what is known about the impact of family planning programs on behavior and health is derived from research at mat- lab. Since the 1970s, matlab has been the testing ground for a variety of new approaches to delivery of family planning services, many of which the national program later adopted. So, for example, matlab researchers were able to compare the impact on contraceptive use of dif - ferent combinations of outreach services and fixed sites for delivery of care, of vertical family planning services versus integrated maternal and child health care, and of limited contracep - tive choices versus the provision of a broad range of methods available. of course, the family planning program alone can take only partial credit for the increase in demand for and use of contraceptives. During the same 30-year period, life in Bangladesh was improving in many ways, particularly for women, and some of those changes directly affected the likelihood that couples would choose smaller families. Between 1973 and 1996, for example, primary school enrollment increased by 1.8 times for boys and almost tripled for girls. Enrollment in secondary school increased by about 2.5 times for boys and by more than five times for girls. correspondingly, employment opportunities for women have increased, and traditional cultural practices have eroded somewhat in the face of global communication and mass media.

Although these factors are important in fostering greater contraceptive use, they do not over - whelm the independent effect of the availability of family planning services. [. . .] ben85927_02_c02.indd 89 1/20/14 2:32 PM SEcTIon 2.4 Case History—Family Planning in Banglades H [r]esearch found that six factors primarily account for the reproductive change in Bangla - desh: communication between husbands and wives about family planning, desire for chil- dren, women’s education, women’s employment status, access to mass media, and the effects of the family planning program, including availability of contraceptives. In addition, it is likely that program efforts have influenced several of the other factors, including communication about family planning between husbands and wives. Apply Your Knowledge While many developing countries are seeing rapid declines in fertility rates and are approach - ing or entering the final stages of the demographic transition, these trends are not universal.

many African countries still have very high fertility rates, and in some there is even evidence that fertility rates have begun to increase again because of an abandonment of family plan - ning programs. complicating the demographic situation in Africa, however, is the HIV/AIDS epidemic, which has hit sub-Saharan Africa harder than anywhere else on Earth. HIV/AIDS is so widespread in some African countries—Lesotho, Zimbabwe, Botswana, and Zambia—that as much as 20 percent of the adult population is infected. Because HIV/AIDS has hit young and middle-aged adults in these countries especially hard, it’s resulting in highly skewed age dis- tributions, with more young children and older adults. This skewed age distribution is having ripple effects on local economies since HIV/AIDS is killing or disabling economic breadwinners.

Sorting out all of the information on rising fertility rates, declining life expectancy due to HIV/ AIDS, and how this epidemic is impacting different segments of a given population makes the work of demographers in Africa especially difficult. Start by reading this report on how the HIV/AIDS epidemic is impacting population (http://www.prb.org/pdf06/howhivaidsaffects populations.pdf) and then consider these questions:

• How is it possible that even with the impact of HIV/AIDS, Africa’s population is pro- jected to roughly double in the next few decades? • How might the HIV/AIDS epidemic negatively impact the economy of sub-Saharan Africa and how might this lead to continued population growth? • What more could or should be done to address the HIV/AIDS epidemic in sub- Saharan Africa? Balancing Aims The Bangladesh family planning program is far from perfect. Since about 1995, declines in fertility have slowed. many observers have noted opportunities to increase the program’s efficiency, to respond more effectively to women’s needs, and to better link family planning and health. The question of the optimal outreach strategy remains unanswered.

one of the changes introduced into the program, the expansion to provide a broader set of reproductive health services, is clearly a positive development. Some data suggest that during the years when the focus was exclusively on the use of contraception, the death rate during pregnancy and delivery increased slightly because of inattention to services such as antena- tal care and skilled attendance at birth. However, the expansion in the mandate of the pro - gram brings with it difficulties and may be partially responsible for the plateauing of family planning uptake in recent years. ben85927_02_c02.indd 90 1/20/14 2:32 PM Summ ArY & rES ourc ES The current challenges, significant though they are, do not erase the fact that Bangladesh has done something few other countries at its level of social and economic development have been able to accomplish: It has complemented efforts to change attitudes about family size with the provision of family planning services to bring about a sustained and dramatic decrease in fertility. Although the original motivation for the program was to attain demographic aims, the government was able to learn the lessons of history and create a program that rejected coercive approaches and responded to couples’ needs. [. . .] Adapted from Center for Global Development, Case 13—Reducing Fertility in Bangladesh. Retrieved from http:// www.cgdev.org/doc/millions/ mS_case_13.pdf and http://www.cgdev.org/section/initiatives/_active/millions saved/studies/case_13 . Used with permission from Center for Global Development. Summary & Resources chapter Summary Though it may be difficult to imagine, the human race likely came close to extinction on several different occasions during our millions of years of existence on this planet. only in the last few hundred years, a mere blip on the record of human history, have we created the conditions that have allowed the human population to grow at an exponential rate. our evolutionary suc - cess has changed the world fundamentally with a population growth of perhaps a few million (at the start of the agricultural revolution 12,000 years ago) to almost 10 billion this century.

We are now the dominant species on the planet in all respects. And the ecological impacts of our dominance, as evidenced by our staggering consumption and technological progress, can be felt in every corner of the world. Such changes in population and their impact require careful study so that scientists can understand and propose ideas for resource management.

In order to keep track of population trends over time, researchers developed the field of demography. Demographers focus on a few key variables—including birth rates, death rates, and fertility rates—to learn and predict how a population changes through time. Demogra - phers have identified the main cause of the exponential growth in human population of the past 200 years as an imbalance between death rates and birth rates. Throughout most of human history, both birth and death rates remained high, but roughly even, and so the popu - lation stayed the same as well. Advances in science, medicine, sanitation, and nutrition over the past two hundred years have led to longer life expectancies and a decline in death rates.

Because birth rates did not immediately decline, as death rates went down, total human pop- ulation increased. Today, birth rates in many countries have dropped to levels close to death rates, and their populations have begun to stabilize. However, other countries are still in the midst of a demographic transition toward low overall birth and death rates. reducing birth rates is the focus of most population policy, and there is much debate over what approaches to use. Indeed, debates between and among political, social, and religious spheres rage over whether stronger, more coercive measures are needed to reduce birth rates. Also, a growing number of environmental scientists now recognize that in addition to absolute num- bers, affluence and the consumption patterns of individuals in a given population also have an impact on the environment. The links between growing human numbers, rising levels of affluence and consumption, and impacts on the environment will be examined more closely in the following chapters. In particular, chapter 3 examines methods for feeding a growing human population that is predicted to reach 9 or 10 billion while also managing the envi- ronmental impact on the planet. Subsequent chapters will consider how rising populations ben85927_02_c02.indd 91 1/20/14 2:32 PM Summ ArY & rES ourc ES and rates of consumption impact land use, biodiversity, water consumption, energy use, and waste generation. Working Toward Solutions Generally speaking, we can think of approaches to reducing fertility as being either direct or indirect. Direct approaches include increasing the availability and use of contraceptives and family planning services. Some countries have combined contraceptive availability and family planning services with economic incentives or rewards and punishments to encourage more couples to make use of these services. china, for example, instituted a one-child-per-family policy in 1979 to help address rapid population growth in that country. Families who had only one child were rewarded with better health care, educational opportunities, housing, and employment. Families with more than one child were denied these rewards and even subject to fines.

Indirect approaches, on the other hand, focus on changing the context within which women and couples make decisions about family size. There is strong evidence, for example, that women with higher levels of education have fewer children. This is because young women who are better educated tend to have greater employment prospects and to marry later. Like- wise, improved access to infant and child health care, especially in poorer countries, has been shown to help reduce fertility rates. When couples are confident that their young children will survive to adulthood, they tend to have fewer children.

The International conference on Population and Development (I cPD), held in cairo, Egypt in 1994 helped to shift the focus of population policy from primarily direct approaches to indi - rect ones. Today, efforts to provide increased education to young girls and women, improved health care for infants and children, and women with more opportunities for economic inde- pendence are seen as paying a “double dividend.” They help reduce fertility rates while also reducing poverty and social injustice. To learn more about these efforts and what you might do to support them, consider the following sources of information.

• Start with this fascinating 10-minute video by Global Health expert Hans rosling on how better education, health care, and economic opportunity are reducing fertility rates around the world: http://www.ted.com/talks/hans_rosling_on_global_population _growth.html. • read more about the International conference on Population and Development and how it shifted the focus of population policy from direct to indirect approaches: http:// www.unfpa.org/public/icpd . • Learn more about the link between increased educational opportunities for girls and women and lower fertility rates through these reports: http://www.prb.org/pdf07 /powerfulpartners.pdf, http://www.un.org/ news/Press/docs/2011/pop994.doc.htm , and http://www.guttmacher.org/pubs/journals/2105295.html . • learn more about a concept known as microfinance, where poor people, especially women, are provided with small loans to help them start their own business and pull themselves out of poverty: http://www.microfinancegateway.org/p/site/m/ , https:// www.microplace.com/ , and http://www.grameenfoundation.org/what-we-do /financial-services . ben85927_02_c02.indd 92 1/20/14 2:32 PM Summ ArY & rES ourc ES Post-Test 1. Which stage is characterized with an equal birth rate and death rate in developing countries? a. Pre-industrial stage b. Transitional stage c. Industrial stage d. Post-industrial stage 2. Which country has the fastest growing amount of carbon emissions from fossil fuels? a. u nited States b. Africa c. England d. c hina 3. Living standards and rates of consumption in much of Africa are very low, and yet some demographers and environmental scientists are concerned about the future environmental impacts of population on that continent. Based on the I 5 PAT for- mula this is because Africa has a. a declining A factor. b. a rising T factor. c. a rising A factor. d. a rising P factor. 4. Beyond the availability of family planning and contraceptive services, demographers know that better education and opportunities for young girls and women can have a powerful impact on fertility rates. This is because a. well-educated women tend to have more children. b. well-educated women tend to have fewer children. c. well-educated women tend not to get married. d. well-educated women can read the instructions on contraceptive packages. 5. The rapid growth in global population over the past 100 years is due primarily to a. rising birth rates. b. declining death rates. c. increased immigration. d. natural population change. 6. The Indian state of Kerala has achieved remarkable declines in fertility in recent decades. Demographers attribute this mainly to a. improvements in female literacy rates. b. improvements in agriculture. c. higher death rates. d. outmigration of young men. 7. The number of bikes and bike paths fall into which category of the I 5 PAT equation? a. Impact b. Population c. Affluence d. Technology ben85927_02_c02.indd 93 1/20/14 2:32 PM Summ ArY & rES ourc ES 8. Which of the following was no T one of the main elements of Bangladesh’s successful population program? a. The deployment of women as outreach workers b. The provision of free cell phones to all families c. The provision of contraceptives d. The establishment of family planning clinics Answers 1. d. Post-industrial stage. The answer can be found in section 2.1. 2. d. china. The answer can be found in section 2.2. 3. d. a rising P factor. The answer can be found in section 2.3. 4. b. well-educated women tend to have fewer children. The answer can be found in section 2.4. 5. b. declining death rates. The answer can be found in section 2.1. 6. a. improvements in female literacy rates. The answer can be found in section 2.2. 7. d. Technology. The answer can be found in section 2.3. 8. b. The provision of free cell phones to all families. The answer can be found in section 2.4. Key Ideas • Demography is the study of how populations change over time. Demographers examine birth rates, death rates, fertility rates, and patterns of immigration and emigration to understand and predict changes to a given population. • For most of human history societies were characterized by relatively high birth rates and death rates, with population remaining constant. Advances in science, medicine, sanitation, and food production brought down death rates rapidly while birth rates, at least for a time, remained high. During this period human population grew rapidly. • The process of declining death rates followed by declining birth rates is known as the demographic transition. most developed countries have already completed the demographic transition and have stable or even declining populations. Developing countries are in various stages of the demographic transition. • The relatively recent (last 200 years) explosion in the human population was due almost entirely to people living longer and declining death rates, not to people hav- ing more children than before. • As fertility rates drop around the world to replacement levels, demographers expect global population to stabilize at somewhere between 9 and 11 billion people. • Policy approaches that improve access to health care, education, and economic opportunity—especially for women—have been found to be just as effective at reducing fertility rates as more coercive techniques such as mandatory sterilization. • Bangladesh provides a good example of how fertility rates and population growth can be brought down without the use of coercive measures. The family planning program in Bangladesh focused on a combination of more widespread contracep - tive availability, better health care and education, and improving the status of women in society. • The I 5 PAT equation shows the relationship between the environmental impact (I) of a given population and its population size (P), level of affluence (A), and tech - nology choices (T). • The ecological footprint concept can be used to illustrate differences in affluence and technology between different countries around the world. ben85927_02_c02.indd 94 1/20/14 2:32 PM Summ ArY & rES ourc ES antenatal care medical care given to a woman during her pregnancy.

demographic transition The process through which a country moves from rela - tively high birth and death rates to relatively low birth and death rates. demography The study of statistics— births, deaths, income, or the incidence of disease—that illustrate the changing struc- ture of human populations. ecological footprint A measure of how much land and water area is necessary to support an individual or group of people. emigration movement of people out of a region, thus decreasing the region’s population.

exponential growth The accelerating population growth that occurs when optimal conditions allow a constant rate of growth over a period of time. human fertility The average number of children a woman will have over her lifetime. human population dynamics Patterns or processes that affect growth or change with the human population. immigration movement of people into a region, thus increasing the region’s population.

industrial stage Third stage of demo - graphic transition during which the birth rate drops, thereby causing population growth to slow.

I 5 PAT An equation that shows the rela- tionship between environmental impacts and the forces that cause them, where I rep- resents the impact, P the size of the popula- tion, a the average affluence or consumption per individual, and T a measure of technol- ogy that drives the consumption.

J curve A curve on a graph resembling the letter “J” that can represent prolonged expo- nential growth. natural population change The increase or decrease of a population size based on birth rates and death rates. critical Thinking and Discussion questions 1. As countries industrialize, stabilization and demographic transition occurs.

Describe these processes and the major factors that contribute to the demography of developed nations. 2. In discussing decreased fertility rates in India, the Kerala model’s success is based on higher literacy rates among female schoolchildren. What is the relationship between literacy and fertility rates? How does a general empowerment for women—as seen in the Bangladesh model—decrease fertility rates? 3. What effect does population have on resource consumption and global environmen- tal impact? Is there a direct correlation between population numbers and carbon emissions? 4. Why is our ecological footprint larger than the direct space we occupy? consider your footprint in the context of your population’s I 5 PAT equation. 5. Humans are constantly innovating ways to produce and consume material resources.

What sort of efforts must be considered about our production and consumption hab - its in order to sustain the global population? Key Terms ben85927_02_c02.indd 95 1/20/14 2:32 PM Summ ArY & rES ourc ES population dynamics Patterns or pro- cesses that affect growth or change within a population. post-industrial stage Fourth stage of demographic transition during which the birth rate continues to fall until it is equal to the death rate, thereby causing no or nega- tive population growth. pre-industrial stage First stage of demo - graphic transition characterized by high birth and death rates, wherein the popula - tion grows slowly if at all. replacement fertility The average number of children a couple must produce in order to “replace” themselves; this number is greater than two because some children die before reaching reproductive age. transitional stage Second stage of demographic transition during which the birth rate remains high but the death rate decreases, resulting in rapid population growth. Additional resources For more information and insights into the study of demographics, check out the follow- ing links: • An easy way to see how exponential growth and population doubling can lead to dramatic outcomes: http://www.worldpopulationbalance.org/exponential-growth -tutorial/bacteria-exponential-growth.html • unit 5 of The Habitable Planet project provides a lot of detail on demographics:

http://www.learner.org/courses/envsci/unit/text.php?unit=5 • This 20-minute video by Hans rosling provides an incredible view into how popula - tion dynamics work and change over time: http://www.ted.com/talks/hans_rosling _shows_the_best_stats_you_ve_ever_seen.html • The international database of the u.S. census Bureau provides detailed population information for nearly every country in the world: http://www.census.gov/population /international/data/idb/informationGateway.php • This site allows you to see how changes in birth rates and death rates can alter population trends over time. Start by choosing a country in the upper-right portion of the window. Then modify the birth rates or death rates under “simulator param- eters.” next, click “run” or repeatedly click “step” under “simulator controls” to see how changes you made can alter population trends going forward: http://www .learner.org/courses/envsci/interactives/demographics/demog.html For more information on population policy and trends going forward, check out the follow- ing links: • World population reached seven billion in october 2011, and there was a lot of media coverage at the time. For more on this historical event, check out: ❍ http://ngm.nationalgeographic.com/7-billion ❍ http://news.blogs.cnn.com/2011/10/26/the-buzz-behind-7-billion -people-a-milestone-and-a-warning/ ben85927_02_c02.indd 96 1/20/14 2:32 PM Summ ArY & rES ourc ES ❍ http://www.time.com/time/specials/packages/0,28757,2097720,00 .html ❍ http://www.scientificamerican.com/report.cfm?id=7-billion-human -population • A 10-minute PBS video on population policy: http://video.pbs.org/video /2056734941/ • An entertaining 14-minute video detailing the unique way in which Thailand, and its Health minister known as “ mr. condom,” approached its population policy: http:// www.ted.com/talks/mechai_viravaidya_how_mr_condom_made_thailand_a_better\ _place.html For more information on the I 5 PAT concept and ecological footprints, check out the follow - ing links: • A 14-minute video looking at differences in consumption patterns between rich and poor through the eyes of four women struggling to provide for their families: http:// populationaction.org/videos/weathering-change/ • A world map deliberately distorted to show differences in car ownership between rich and poor countries: http://www.worldmapper.org/posters/worldmapper _map31_ver5.pdf • An overview of the ecological footprint concept that includes links to average foot- prints for different countries: http://www.footprintnetwork.org/en/index.php /GF n/page/footprint_basics_overview/ These three TED talks provide very different perspectives and insights into the HIV/AIDS epidemic in Africa: • http://youtu.be/3q rtDnsnSwk • http://youtu.be/xGXt3G uJ-9w • http://youtu.be/T3vZbEJX cAE ben85927_02_c02.indd 97 1/20/14 2:32 PM ben85927_02_c02.indd 98 1/20/14 2:32 PM