1 Environmental Science A Study of Interrelationships Tenth Edition Enger Smith Chapter 8 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

2 Human Population Issues Chapter 8

3 Outline Population Trends and Implications – Biological Factors – Social Factors – Political Factors Population Growth - Standard of Living Population and Poverty – Hunger and Food Demographic Transition United States Population Picture Immigration

4 World Population Characteristics The world can be divided into two segments based on economic development. – More-developed countries typically have per capita income exceeding $10,000.  Expected to grow 4% by – Less-developed countries typically have a per capita income less than $5,000.  Expected to grow 55% by  Increase to 8 billion.

5 Population Growth and Economic Development

6 Human Population Trends and Implications Largest population increase expected in poor, underdeveloped countries. – Population density relates the size of the population to available resources.  Countries with abundant resources can sustain higher population densities than resource-poor countries.  Generally believed the quality of life for many people in the world would improve if the population grew at a slower rate.

7 Human Population Trends and Implications Several factors determine the impact of a society on natural resources. – Natural Resource Availability – Size of Population – Land Area Occupied – Degree of Technological Development  Affluence affects resource use.

8 Factors That Influence Population Growth Biological Factors – Demography - Study of populations and their characteristics.  Birth rate usually exceeds death rate.  Size of population must increase.  More-developed countries typically have low infant mortality rates, while less-developed countries have higher mortality rates.

9 Biological Factors Total Fertility Rate (TFR) - Number of children a woman has during her lifetime. Replacement Level Fertility - Number of children needed to replace everyone in the population. – Varies between regions (2.1). Zero Population Growth - Birth rate equals death rate. Age Distribution - Number of people of each age in the population.

10 Social Factors Reducing fertility rates would be advantageous, especially in LDC’s. – Not everyone agrees. Major social factor determining family size is the role of women in society. – In male dominated cultures, traditional role of women is to marry and raise children.

11 Social Factors Lack of education opportunities for women reduces their options. – When level of education increases, fertility rates fall.  Financial independence leads to marriage later in life.  Increased use of birth control.

12 Social Factors Early marriages foster high fertility rates. – In Africa, 17% of births are to women in the year-old range.  Total Fertility Rate of 5.3% Breast Feeding – During the months a woman is breast feeding, she is less likely to become pregnant again.

13 Social Factors Some cultures (women) desire large families: – Future Pension – Young children can bring in income.  Underdeveloped world - children are an economic gain.  Developed world - children are an economic drain.

14 Political Factors Governments can either reward or punish high fertility rates. – Several European countries are concerned about low birth rates.  Polices to encourage children.  Funded Maternity Leave  Childcare Facilities  Child Tax Deductions

15 Political Factors Most developing countries are concerned that population growth is too rapid. – Programs to limit growth:  Family Planning  Delay Age of First Marriage  One-Child Policy

16 Political Factors Immigration Policies – Birthrates are so low in some countries, that immigration is encouraged to offset a potential decline in the number of working-age citizens. – Developed countries are under intense pressure to accept immigrants.  Standard of Living

17 Population Growth and Standard of Living Appears to be an inverse relationship between a country’s growth rate and its average standard of living. Standard of living difficult to quantify since various cultures have different desires. – Economic Well-Being – Health Conditions – Social Status and Mobility

18 Population Growth and Standard of Living Gross National Income (GNI) - Index measuring total goods and services generated by citizens of a country. – Gross National Income Purchasing Power Parity (GNIPPP) used to account for varying prices of goods and services between countries.

19 Population and Poverty - A Viscous Cycle Poor People: – Cannot afford birth control. – Need multiple avenues to obtain money. – Have little access to health care. Women in poor countries are usually poorly educated and are monetarily dependent on husbands. – High infant mortality rates spur desire for large numbers of offspring.

20 Population and Poverty - A Viscous Cycle Potential solutions to breaking the cycle: – Economic well-being is tied to solving population problem.  Rich countries must reduce consumption rates. – Educational status of women must be promoted. – Increased access to birth control and heath care.

21 Hunger, Food Production and Environmental Degradation As human population grows so does the demand for food. – Most people in developed countries must purchase their own food. – Most people in less-developed countries must grow their own food. Human populations can only increase in size if other plant and animal populations decrease in size.

22 Hunger, Food Production and Environmental Degradation People in less-developed countries generally feed at lower trophic levels than those in developed world. – Long-term environmental health may be sacrificed for short-term population needs. Many people in more-developed countries suffer from overnutrition. – 55% of North Americans are overweight, and 25% are obese.

23 Population and Trophic Levels

24 Hunger, Food Production and Environmental Degradation Humanitarian Food Aid – Temporary relief of symptoms. – Works against self-reliance. – Emphasis must be on self-sufficiency.

25 Demographic Transition Demographic Transition - Model of population growth based on historical, social, and economic development, of Europe and N. America. – Stable Pop. (high birth and death rates) – Death Rate Falls - Population Grows – Industrialization - Birth Rate Falls – Death Rates and Birth Rates Equilibrate

26 Demographic Transition

27 Demographic Transition Comfortable - This is a comfortable model, because it suggests industrialization will naturally lead to population stabilization. – Problem - Can a model developed in Europe and N. America be applied to less-developed countries ?  Resources are no longer abundant.  Human population is growing much faster than before.

28 United States Population Picture United States population had a post-war baby boom period, significantly affecting population trends. –  Created population bulge.  As members of this group have raised families, they have had a significant influence on U.S. population growth and trends.

29 Changing Age Distribution of U.S. Population

30 Baby Boomers Baby Boomers encouraged growth of industries needed by young families. – Today these babies are having babies of their own. People are now living longer. – Growing need now for services for the elderly.

31 Immigration U.S. population is still growing 1.1% per year. – 0.6% natural increase – 0.5% immigration  Immigration projected to be 50% of population growth by 2050.

32 Immigration Immigration policy sends mixed signals: – Strong measures used to reduce illegal immigration across southern borders. – Illegal immigrants add to state education and health care costs. – Some segments of U.S. economy heavily use immigrant workers. – U.S. policy allows reuniting families of U.S. residents.

33 Likely Consequences of Continued Population Growth Differences in standard of living between developed and less-developed countries will remain significant. – Largest population increase will be in less-developed countries.

34 Likely Consequences of Continued Population Growth Developed countries may have to choose: – Helping developing nations. – Allowing increased immigration from less- developed nations. – Isolation from problems of developing nations.

35 Review Population Trends and Implications – Biological Factors – Social Factors – Political Factors Population Growth - Standard of Living Population and Poverty – Hunger and Food Demographic Transition United States Population Picture Immigration

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