AP Environmental Science Human Population: Growth, Demography and Carrying Capacity World Population Clock © Brooks/Cole Publishing Company / ITP

Outline 1. Factors Affecting Human Population Size birth and death rates 2. Population Age Structure age structure diagrams, developing vs. developed countries 3. Solutions: Stabilizing Human Population computer models, demographic transition 4. Case Studies United States, India, China 5. Human Population and Sustainability © Brooks/Cole Publishing Company / ITP

1. Factors Affecting Human Population Size Human population is currently growing exponentially. What will be the ultimate size of the human population? What is Earth's carrying capacity? Population Crash Video Clip Fig.1–1 © Brooks/Cole Publishing Company / ITP

Factors Affecting Human Population Size Population change is calculated as the difference between individuals entering and leaving a population: Population Change Births + Immigration Deaths + Emigration – = birth rate is reported as the number of births per year/population death rate is reported as the number of deaths per year/population zero population growth (ZPG) occurs when factors that increase and decrease population size balance. NOTE: when considering world population growth rates, immigration and emigration play no part (YET!) © Brooks/Cole Publishing Company / ITP

Demography Demography: the study of changes in size, composition and distribution of human populations. Demographers study these trends, as well as their causes and consequences.

Crude Birth and Death Rates Crude birth rate: number of births per year/1000 people. Crude death rates calculated in the same way. See Fig 10-3 Developing countries typically have higher crude birth and death rates—Africa #1 Birth rates in developed countries: 0.1% Birth rates in developing countries: 1.5% Birth rates and death rates decreasing worldwide Death rates decreasing faster than birth rates, especially in developing countries ***Earth’s population increase is greatly due to decreased death rates.

World 21 9 All developed countries 11 10 All developing countries 24 8 Average crude birth rate Average crude death rate World 21 9 All developed countries 11 10 All developing countries 24 8 Developing countries (w/o China) 27 9 © 2004 Brooks/Cole – Thomson Learning

© 2004 Brooks/Cole – Thomson Learning Africa 38 14 Latin America 22 © 2004 Brooks/Cole – Thomson Learning 6 Asia 20 7 Oceania 18 7 United States 14 8 North America 14 8 Europe 10 12

Population Change Population growth: Pop = Pop0 + (b + i) - (d + e) The annual rate of population increase is generally expressed as a percentage. Note the distribution of growth rates in 1998. To figure the rate: (Pop - Pop0) / Pop0 X 100 OR use the rule of 70! © Brooks/Cole Publishing Company / ITP

Population Change ***Between 1963 and 2004 the world’s annual population growth dropped 41% from 2.2% to 1.25%. In this same time, the world population doubled to 6.4 billion. A small, exponential population growth rate can still have large effects, especially if the population base is large. The world is currently adding another New York City every month.

The Most Populous Countries The world’s top five most populated countries : #1 China1.3 billion #2 India1.1 billion These two countries together make up 37% of the world’s total population #3 United States #4 Indonesia #5 Brazil See Figure 10-4 © Brooks/Cole Publishing Company / ITP

© 2004 Brooks/Cole – Thomson Learning China © 2004 Brooks/Cole – Thomson Learning 1.3 billion 1.4 billion India 1.1 billion 1.4 billion USA 294 million 349 million Indonesia 219 million 308 million Brazil 179 million 211 million Pakistan 159 million 229 million Russia 144 million 137 million Bangladesh 141 million 205 million Japan 128 million 121 million Nigeria 137 million 206 million 2004 2025

Population Size and Fertility Fertility: the number of births that occur to an individual woman or in a population. Two types of fertility rates that affect a country’s population size and growth rate: 1)Replacement-level fertility rate 2)Total fertility rate (TFR) © Brooks/Cole Publishing Company / ITP

Replacement-Level Fertility vs. Total Fertility Rate Replacement-level fertility: the number of kids a couple must have to replace themselves. 2.1 developed, 2.5 developing due to fact that some females die before reproducing Reaching replacement levels does not mean immediate halt in population growth b/c many future parents are still alive.

Replacement-Level Fertility vs. TFR Total fertility rate: the average number of kids a woman typically has during her reproductive years. These have dropped sharply since 1950’s Developed: 2.51.5 Developing 6.53.1 ** Highest currently in Africa In the U.S. the time of the highest TFR was in the 1950’s after WWII. This was called the “Baby Boom.”

© 2004 Brooks/Cole – Thomson Learning World 5 children per woman 2.8 Developed countries 2.5 1.6 © 2004 Brooks/Cole – Thomson Learning Developing countries 6.5 3.1 Africa 6.6 5.1 Latin America 5.9 2.6 Asia 5.9 2.6 Oceania 3.8 2.1 North America 3.5 2.0 Europe 2.6 1.4 1950 2004

Total Fertility Rate The expected population in future years depends on the world’s projected averageTFR (high:2.5, medium:2.0, low:1.5) 97% of the growth in all three estimates is projected to take place in developing countries. See Fig 10-5 and 10-6

Population (billions) 12 11 High High 10.6 10 Medium Low 9 Medium 8.9 8 Population (billions) 7 6 Low 7.2 5 4 3 2 1950 1960 1970 1980 1990 2000 2010 2020 2030 2040 2050 Year

Total Fertility in the United States Total fertility in the United States had a major increase during the "baby boom" (1946–64) and is now hovering just below replacement level. Fig.11–9 © Brooks/Cole Publishing Company / ITP

Factors Affecting Fertility Rates The following are significant factors that decrease human fertility levels: increase in average level of education and affluence decrease in importance of child labor increased urbanization—access to family planning increased cost of raising and educating children increased educational and employment opportunities for women decreased infant mortality higher average age of marriage greater availability of private and public pensions greater availability of reliable birth control greater availability of legal abortions change in religious beliefs, traditions, and cultural norms away from encouraging large families. © Brooks/Cole Publishing Company / ITP

Birth Control Typical effectiveness of birth control methods in the United States The US is the #1 industrialized country for teen pregnancy rate © Brooks/Cole Publishing Company / ITP

Birth Control Typical effectiveness of birth control methods in the United States (continued): © Brooks/Cole Publishing Company / ITP

Death Rates Infant death rates are lower in developed countries than developing countries. Fig.11–12 © Brooks/Cole Publishing Company / ITP

Death Rates Infant mortality: the number of babies of every 1,000 born who die before their first birthday. At least 8 million infants (most in developing) die of preventable causes during their first year of life22,000 per day = 55 jumbo jet crashes with no survivors. **Life expectancy and infant mortality rates (deaths/1000 before first birthday) determine health of people in a country.

Birth and Death Rates Over Time The rapid growth in the world's population has not resulted from an ↑ in birth rates, but a ↓ in death rates. Death rates have ↓ markedly during past 100 years Birth rates have also ↓, but not as fast as death rates The increasing difference between birth and death rates is what has lead to exponential population growth The patterns of change in birth and death rates over time are different for developed vs. developing countries. © Brooks/Cole Publishing Company / ITP

Birth and Death Rates Over Time In developed countries decreases in death rates are being accompanied by decreases in birth rates over time. Fig.11–11a © Brooks/Cole Publishing Company / ITP

Birth and Death Rates Over Time In developing countries decreases in death rates have not been accompanied by as large of decreases in birth rates over time, leading to major population increase. Fig.11–11b © Brooks/Cole Publishing Company / ITP

2. Population Age Structure Age structure refers to the proportion of the population in each age class: prereproductive (0–14 years) reproductive (15–44 years) postreproductive (45 and up) © Brooks/Cole Publishing Company / ITP

Population Age Structure Age structure of a rapidly growing vs. a slower growing population. Rapidly growing populations have pyramid–shaped age structures, with large numbers of prereproductive individuals. Slower growing populations have a more even age distribution. Fig.11–13a © Brooks/Cole Publishing Company / ITP

Population Age Structure Age structure of populations with zero growth vs. negative growth. Populations with zero population growth have nearly equal proportions of prereproductive and reproductive individuals; whereas populations with negative growth have a greater proportion of reproductive than prereproductive individuals. Fig.11–13b © Brooks/Cole Publishing Company / ITP

Population Age Structure Developing countries are expected to continue to have a pyramid shape through the year 2025, although the age structure will become somewhat more evenly distributed. Fig.11–14a © Brooks/Cole Publishing Company / ITP

Population Age Structure Populations of developed countries are expected to have an increasingly even age distribution through the year 2025. Age Structure Video Clip from hippocampus.org Fig.11–14b © Brooks/Cole Publishing Company / ITP

Population (2004) Population projected (2025) Infant mortality rate United States (highly developed) 294 million 179 million Brazil (moderately developed) 137 million Nigeria (less developed) Population projected (2025) 349 million 211 million 206 million Infant mortality rate 6.7 33 100 Life expectancy 77 years 71 years 52 years Fertility rate (TFR) 2.0 2.2 5.7 %Population under age 15 21% 30% 44% % Population over age 65 12% 6% 3% Per capita GDP $36,110 $7,450 $800 © 2004 Brooks/Cole – Thomson Learning

Population Age Structure Population age structure of the United States continues to show a bulge as the baby boom generation ages. This has been compared to watching a boa constrictor swallow a pig. Fig.11–15 © Brooks/Cole Publishing Company / ITP

3. Solutions: Stabilizing Human Population In 1972 the projections of a model, published in The Limits to Growth, indicated that if current economic, resource use, and population trends continue then we can expect economic and ecological collapse in the next century. the results of this admittedly crude model challenged basic assumptions of industrial societies that there are no limits to industrial and population growth twenty years later the authors updated their work in Beyond the Limits: Confronting Global Collapse, Envisioning a Sustainable Future (Donella Meadows et al. 1992) despite limitations, computer models are an effective means for exploring possible future scenarios. © Brooks/Cole Publishing Company / ITP

Computer Models of Human Population This computer model projects what might happen if the world's population and economy continue to grow exponentially at 1990 levels. Fig.11–18 © Brooks/Cole Publishing Company / ITP

Computer Models of Human Population This computer model projects how we can avoid overshoot and collapse to make a fairly smooth transition to a sustainable future by stabilizing fertility at two children per couple. Fig.11–19 © Brooks/Cole Publishing Company / ITP

Demographic Transition A generalized model of the four stages of demographic transition. **Explains how death rates fall before birth rates when a country becomes industrialized. Fig.11–20 © Brooks/Cole Publishing Company / ITP

Demographic Transition 1) Preindustrial Stage: both birth and death rates are relatively high (harsh living conditions) and approximately equal, such that the population does not increase, and the population size is small. Fig.11–20 © Brooks/Cole Publishing Company / ITP

Demographic Transition 2) Transitional Stage: The population grows rapidly b/c death rate decreases markedly due to industrialization, increased food production, and improved health care. Birth rates remain relatively high, so the population grows rapidly. Fig.11–20 © Brooks/Cole Publishing Company / ITP

Demographic Transition 3) Industrial Stage: Birth rate drops and eventually approaches a balance with death rate, leading to a slowing of population growth. Fig.11–20 © Brooks/Cole Publishing Company / ITP

Demographic Transition 4) Postindustrial Stage: Birth rate and death rates approximately balance, zero population growth (ZPG) is attained, and the population stabilizes at a size much higher than the preindustrial size. If birth rate declines below death rate negative population growth may even be attained. Fig.11–20 © Brooks/Cole Publishing Company / ITP

Demographic Transition Most developing countries are in the transitional stage because death rates have fallen more than birth rates Reasons some analysts believe some of the conditions needed for the developing countries to develop are no longer available to some developing countries Skilled workers to compete in today’s economy Lack of capital and resources for economic development Sharp rise in debt to other countries, leaving little for improvement Less economic assistance since 1980’s Demographic transition at hippocampus.org

4. Case Studies Immigration in the United States: Fig.11–17 As fertility decreases, immigration has become a major source of population increase in the U.S. In 1998 the U.S. received about 935,000 legal immigrants and 400,000 illegal immigrants--40% of our annual population growth! Working immigrants boost the economy in the long run Increasing levels of legal and illegal are expected. Fig.11–17 © Brooks/Cole Publishing Company / ITP

Case Studies Population Control in India: Fig.11–16 In 1952 India began the first national family planning program The program has been disappointing in India because of poor planning, inefficiency, low status of women, extreme poverty, and lack of funds Couples still have an average of 3.5 children because of the belief that they need children to work and care for them in old age. Fig.11–16 © Brooks/Cole Publishing Company / ITP

Family Planning Worldwide Provide info about prenatal care Help parents space births Help parents regulate family size Globally family planning: Raised the use of modern contraception by married women in developing countries from 10% in 1960’s to 50% in 2004 Responsible for at least 55% of the drop in TFR’s for developing countries from 6 in 1960 to 3.1 in 2004

Case Studies Population Control in China: Fig.11–16 Since 1970, China, with the world's largest population, has initiated efforts to better feed its people and control population growth Family planning successful Strict population control measures prevent couples from having more than one child ** See book Although considered coercive, the policy is significantly slowing population growth. **See Fig 10-22 Fig.11–16 © Brooks/Cole Publishing Company / ITP

India China Percentage of world 17% population 20% Population 1.1 billion 1.3 billion Population (2025) (estimated) 1.4 billion 1.4 billion Illiteracy (%of adults) 47% 17% Population under age 15(%) 36% 22% Population growth rate (%) 1.7% 0.6% Total fertility rate 3.1 children per woman (down from 5.3 in 1970) 1.7 children per woman (down from 5.7 in 1972) Infant mortality rate 64 32 Life expectancy 62 years 71 years GDP PPP per capita $2,650 $4,520

5. Human Population and Sustainability How can governments reduce population growth? improve access to family planning and reproductive health care improve heath care for infants, children, and pregnant women encourage development of national population policies improve equality between men and women increase access to education, especially for girls increase the involvement of men in child rearing and family planning reduce poverty reduce and eliminate unsustainable patterns of production and consumption. © Brooks/Cole Publishing Company / ITP

Women Empowerment and Sustainability Three factors that lead to women having fewer, healthier children Education, job outside home, rights Women do 60-80% of the work associated with growing food, gathering fuel and hauling water in rural areas Globally women account for 2/3 of all hours worked but receive only 10% of the world’s income and 2% of the world’s land. Achieving equality would slow population growth, promote freedom, reduce poverty and slow environmental degradation.