Presentation is loading. Please wait.

Presentation is loading. Please wait.

Human Population Growth

Similar presentations

Presentation on theme: "Human Population Growth"— Presentation transcript:

1 Human Population Growth

2 Factors Affecting Human Population Size
Births Deaths Migrations Immigration: individuals moving into a pop. Emigration: individuals moving out of a pop. Population Change= (births+immigration)-(deaths+emigration) **When births and immigration is greater than deaths and emigration, the population will increase

3 World Population Rate of annual pop change is expressed as a percentage: birth rate-death rate The U.S. had a birth rate of 14.6 live births per 1,000 population in one year, compared to India’s birth rate of 22.2 in that same year. The death rate in that year for the U.S. was 8.3 deaths per 1,000, compared to India’s rate of Calculate the population growth rates (%) for both countries. U.S = 0.6% India = 1.6%

4 World Population Exponential growth has not disappeared, but its occurring at a slower rate Between 1963 and 2002, the population rose from 3.2 to 6.2 billion 79 million people were added in 2002, compared to 69 million in 1963 when the world’s pop growth rate was at its highest

5 Human Population Growth over Time
Before agricultural revolution: 1-3 million humans, hunter/gatherers, Earth Wisdom-natural cycles serve as models for human behavior 8000 BCE-5000BCE: ~50 million humans, increases due to agricultural revolution 5000 BCE-1 BCE: ~200 million humans, Frontier Worldview-undeveloped land as a hostile wilderness to be conquered, exploited resources 0 BCE-1300 CE: ~500 million humans CE: ~600 million humans, plagues reduced population growth rate

6 Human Population Growth over Time
1650-present: ~7 billion humans, reductions in death rates, increase medical technology, Planetary Management-as we are the planet’s most important species, we are in charge of earth, we will develop new resources so should not worry about using them sustainably Present-2050: ~9 billion (?), Earth Wisdom-resources are limited so should be conserved, we should encourage sustainable use of resources because the earth exists for all nature

7 Fertility Rates Replacement Level Fertility- # of children that a couple needs to have in order to replace themselves (2.1 in developed countries/2.5 in developing countries) Total Fertility Rate (TFR)-an estimate of the # of children a woman will have during childbearing years (based on the previous year)

8 United States Historical Trend in Total Fertility Rate
: birth rates dropped due to urbanization 1930’s: stayed low because of the Great Depression 1940’s: rising again 1957: TFR=3.7 children/woman, highest : Baby Boom : Baby Bust : Echo Boom

9 United States Historical Trend in Total Fertility Rate

10 Factors that Affect Average Birth Rate and TFR
Children are part of the labor force- Urbanization- High cost of raising and education children- High infant mortality rate- Older average age of marriage-

11 Factors that Affect Average Birth Rate and TFR
High availability of pension systems- Availability of legal abortions- Availability of birth control- Men included in child-rearing responsibilites- Religious beliefs, traditions, cultural norms

12 Factors That Decrease Death Rates
Increased food supply and distribution Better nutrition Medical improvements Increased sanitation Better water supply**

13 Two Indicators of Overall Health
Life expectancy: average # of years people live Global life expectancy: 76 in developed nations/65 in developing nations US: 77 yrs. Africa: 55 Yrs. Infant Mortality Rate: # of babies out of 1000 that die before their first birthday High infant mortality rate indicates insufficient food, poor nutrition, high incidence of infectious disease (water supply)

14 Infant Mortality Rates

15 Population Age Structure
The proportion of the pop of each sex at each age level; used to make pop and economic projections Age levels: Prereproductive (0-14) Reproductive (15-44) Post reproductive (45 and up) Age structure affects population growth Countries with a wide base (lots of people below 15) will increase in size if death rate stays the same

16 Population Age Structure

17 Population Study-Example
Social security crisis

18 Populations Affected by Immigration
U.S. Canada Australia

19 Cultural Carrying Capacity
Different from actual # of individuals an area can support b/c of culture; when land is used to grow feed for cattle it expends more energy thus reducing carrying capacity Eating high on the food chain uses up to 50x more land than eating a vegetarian diet 43% of U.S. is used for grazing or feed for livestock; meat’s impact on the environment is second only to automobiles

20 Demographic Transition
Demography: study of human population As countries become industrialized first death rates, but then birth rates decline Four Stages Preindustrial Stage Tansitional Stage Industrial Stage Postindustrial Stage

21 Preindustrial Stage Little population growth because of harsh conditions High birth AND death rates

22 Transitional Stage Population grows rapidly when industrialization improves High birth rates, lowering death rates Stage that developing nations are in currently

23 Industrial Stage Population growth slows as birth rates drop and eventually approach death rates

24 Postindustrial Stage Birth rate=death rate Zero population growth
U.S., Japan, Europe (some populations are even decreasing)

25 Demographic Transition

26 India 1.1 billion people 16% of world’s people, but only 2.3% of world’s land resources and 2% of world’s forests 70% of water seriously polluted Tried family planning, but not very successful Why?

27 India

28 China 1.3 billion people Since 1970, cut its crude birth rate in half and decreased TFR from 5.7 to 1.8 children/woman How? Free sterilizations/contraception/abortions Couples who have only one child receive: extra food, larger pensions, better housing, free medical care, salary bonuses, free school tuition for their child, and preferential treatment in employment when their child enters the work force

29 China Projected that China’s pop will begin to decline in 2042, but what about their aging population/social security? Should other countries impose such severe restrictions/limitations on human freedoms to achieve pop control?

30 China

31 Cutting Global Population Growth
Provide access to family planning services and reproductive health care Improve health care of infants, children, pregnant women Implement population policies Improve job opportunities for women Increase access to education, especially to women Increase involvement of men in child-rearing Eradicate poverty Reduce/eliminate unsustainable patterns of production and consumption

32 Cutting Global Population Growth
Goal of Cairo Commitment: stabilize pop growth at 7.8 billion by 2050 instead of projected 9-11 billion BTW we are already at 6.7 billion….. World Clock

33 World Population

Download ppt "Human Population Growth"

Similar presentations

Ads by Google