The Human Population and its Impact Chapter 6

Human Exponential Growth For the past 200 years, the human pop. has grown rapidly  J-curve Why? ability to live in most climate zones and habitats modern agriculture = more food Improved sanitation and health care = drop in death rates

Annual Growth Rate Global Pop. growth = 1.21% per year Growth is geographically uneven Fig. 6-3, p. 127

Figure 6.4: This chart shows the populations of the world’s five most populous countries in 2010 and 2050 (projected). In 2010, more than one of every three persons on the earth lived in China (with 19% of the world’s population) or India (with 17%). (Data from United Nations Population Division) Fig. 6-4, p. 127

Cultural Carrying Capacity Maximum # of people who could live in reasonable freedom and comfort indefinitely, without decreasing the ability of the earth to sustain future generations

Factors Affecting Human Population Size Population change equation Population Change = (Births + Immigration) – (Deaths + Emigration) Crude birth rate (CBR) - # live births per 1000 people in a population in a given year Crude death rate (CDR) - # deaths per 1000 people in a population in a given year http://smsh.dadeschools.net/science/aycart/apes/apes.htm 6

Average CBR and CDR http://smsh.dadeschools.net/science/aycart/apes/apes.htm 7

Describing Population Changes Doubling Times - time (years) for a pop. growing at a specified rate to double in size “Rule of 70” - - EX: 2004 world’s pop. growth rate 1.2% doubling time = 70/1.2= 56 years http://smsh.dadeschools.net/science/aycart/apes/apes.htm 8

Fertility fertility rate = number of children born to a woman during her lifetime replacement-level fertility rate = average number of children that couples in a pop. must bear to replace themselves total fertility rate (TFR) = average number of children born to women in a pop. during their reproductive years

Figure 6.5: This graph tracks the total fertility rate for both the more-developed and less-developed regions of the world, 1955–2010, with projections to 2050 (based on medium population projections). Although the world’s average TFR has dropped to 2.5, it will have to drop to around 2.1 to eventually halt the world’s population growth. (Data from United Nations Population Division) Fig. 6-5, p. 130

US Fertility & Birth Rates 76 mil (1900) to 294 mil (2004) Figure 6.6: The top graph shows the total fertility rates for the United States between 1917 and 2010 and the bottom graph shows the country’s birth rate between 1917 and 2010. Question: The U.S. fertility rate has declined and remained at or below replacement levels since 1972. So why is the population of the United States still increasing? (Data from Population Reference Bureau and U.S. Census Bureau) Fig. 6-6, p. 131

Factors Affecting Birth Rates Importance of children as a part of the labor force Cost of raising and educating children Availability of, or lack of, private and public pension systems Infant deaths Urbanization

Factors Affecting Birth Rates Educational and employment opportunities available for women Average age at marriage (or average age at which a woman has her first child) Availability of legal abortions Availability of reliable birth control methods Religious beliefs, traditions, and cultural norms

Factors Affecting Death Rates Increased food supplies and distribution Better nutrition Medical advances Improved sanitation Safer water supplies

Factors Affecting Death Rates Life expectancy - avg. # years a newborn infant can expect to live Infant mortality rate (IMR) - # babies out of every 1000 born who die before their 1st birthday GOOD NEWS BAD NEWS Global life expectancy increased from 48 years to 69 years (77 developed; 67 developing) Poorest, least developed countries life exp. 57 years or less (may drop due to internal strife, AIDS) IMR dropped from 20 per 1000 live births to 7 in developed countries Most infants and children die from fully preventable causes IMR dropped from 118 per 1000 live births to 61 in developing countries http://smsh.dadeschools.net/science/aycart/apes/apes.htm 15

Essential Question What are the factors that influence birth and death rates?

Migration Movement of people into (immigration) and out of (emigration) specific geographic areas Most seek jobs and economic improvement Religious persecution, ethnic conflicts, political oppression, wars and certain types of environmental degradation cause some to migrate

Figure 6.11: This graph shows legal immigration to the United States, 1820–2006 (the last year for which data are available). The large increase in immigration since 1989 resulted mostly from the Immigration Reform and Control Act of 1986, which granted legal status to certain illegal immigrants who could show they had been living in the country prior to January 1, 1982. (Data from U.S. Immigration and Naturalization Service and the Pew Hispanic Center) Fig. 6-11, p. 135

Age Structures The numbers or percentages of males and females in young, middle and older age groups in that population Prereproductive (0-14) Reproductive (15-44) Postreproductive (45 and older)

Figure 6.12: This chart represents the generalized population age-structure diagrams for countries with rapid (1.5–3%), slow (0.3–1.4%), zero (0–0.2%), and negative (declining) population growth rates. A population with a large proportion of its people in the prereproductive age group (far left) has a significant potential for rapid population growth. See an animation based on this figure at CengageNOW. Question: Which of these diagrams best represents the country where you live? (Data from Population Reference Bureau) Fig. 6-12, p. 136

Figure 6.13: Global outlook: These charts illustrate population structure by age and sex in less-developed countries and more-developed countries for 2010. Question: If all girls under 15 were to have only one child during their lifetimes, how do you think these structures would change over time? (Data from United Nations Population Division and Population Reference Bureau) Fig. 6-13, p. 136

Essential Question What is an age structure diagram and what can it be used for?

Slowing Human Population Growth Promote economic development Empower women Promote family planning The Miniature Earth VHEMT

Promote Economic Development Reduce poverty through economic development and universal primary education Demographic transition = as countries become industrialized and economically developed, first their death rates decline and then their birth rates decline

Figure 6.17: The demographic transition, which a country can experience as it becomes industrialized and more economically developed, can take place in four stages. See an animation based on this figure at CengageNOW. Question: At what stage is the country where you live? Fig. 6-17, p. 140

Slow population growth Stage 1: Preindustrial High birth rate High death rate Slow population growth Figure 6.17: The demographic transition, which a country can experience as it becomes industrialized and more economically developed, can take place in four stages. See an animation based on this figure at CengageNOW. Question: At what stage is the country where you live? Fig. 6-17, p. 140

High population growth Stage 2: Transitional High birth rates LOW death rates High population growth Figure 6.17: The demographic transition, which a country can experience as it becomes industrialized and more economically developed, can take place in four stages. See an animation based on this figure at CengageNOW. Question: At what stage is the country where you live? Fig. 6-17, p. 140

Slow population growth Stage 3: Industrial LOW birth rate Low death rate Slow population growth Figure 6.17: The demographic transition, which a country can experience as it becomes industrialized and more economically developed, can take place in four stages. See an animation based on this figure at CengageNOW. Question: At what stage is the country where you live? Fig. 6-17, p. 140

Stage 4: Post-industrial Lower birth rate Stable death rate Declining population growth Figure 6.17: The demographic transition, which a country can experience as it becomes industrialized and more economically developed, can take place in four stages. See an animation based on this figure at CengageNOW. Question: At what stage is the country where you live? Fig. 6-17, p. 140

Empower Women Elevate the status of women Women tend to have fewer children if they are Educated Have the ability to control their own fertility Earn an income of their own Live in societies that do not suppress their rights

Promote Family Planning Family planning = provides educational and clinical services that help couples choose how many children to have and when to have them Most provide info on birth spacing, birth control, and health care for pregnant women and infants Reduces number of abortions and deaths of mom/babies during pregnancy

Promote Family Planning Problems Many pregnancies are unplanned Lack of access to services Expand to include teenagers and sexually active unmarried women Develop programs that educate men Greatly increase research male birth control

Essential Question What are the ways in which we can slow human population growth?