Week 3 Lecture 3.2 Human-population.ppt
- 1. A crowded street in China Fig. 6-1, p. 125
- 2. How Many People Can the Earth Support? • We do not know how long we can continue increasing the earth’s carrying capacity for humans without seriously degrading the life-support system that keeps us and many other species alive. U.S. and World Population Clock • https://www.census.gov/popclock/
- 3. Human Population Growth Continues but It Is Unevenly Distributed (2) • Population growth in developing countries is increasing 9 times faster than developed countries by 2050 • 95% of growth in developing countries and will probably reach 7.5-10.8 billion people • Carrying capacity is the maximum population that a given area can sustain. • Carrying capacity of human is the maximum number of people who could live in reasonable freedom and comfort indefinitely, without decreasing the ability of the earth to sustain future generations.
- 4. Reasons for human population increase 1. Movement into new habitats and climate zones 2. Early and modern agriculture methods 3. Control of infectious diseases through • Sanitation systems • Antibiotics • Vaccines • Health care • Most population growth occurred over last 100 years due to drop in death rates • Growing at a rate of 1.21% per year
- 5. Human Population Growth Fig. 1-18, p. 21
- 6. Population Time Line: 10,000 BC - 2042 Figure 3, Supplement 9
- 7. Where Population Growth Occurred, 1950-2010 Fig. 6-3, p. 127
- 8. Five Most Populous Countries, 2010 and 2050 Fig. 6-4, p. 127
- 9. Science Focus: Projecting Population Change • Why range of 7.8-10.8 billion for 2050? • Too many factors to consider • Demographers must: 1. Determine reliability of current estimates 2. Make assumptions about fertility trends 3. Deal with different databases and sets of assumptions
- 10. World Population Projections to 2050 Fig. 6-A, p. 128
- 11. Fig. 6-B, p. 129 Natural Capital Degradation Altering Nature to Meet Our Needs Reducing biodiversity Increasing use of net primary productivity Increasing genetic resistance in pest species and disease-causing bacteria Eliminating many natural predators Introducing harmful species into natural communities Using some renewable resources faster than they can be replenished Disrupting natural chemical cycling and energy flow Relying mostly on polluting and climate-changing fossil fuels
- 12. What Factors Influence the Size of the Human Population? • Population size increases because of births and immigration, and decreases through deaths and emigration. • The average number of children born to women in a population (total fertility rate) is the key factor that determines population size.
- 13. The Human Population Can Grow, Decline, or Remain Fairly Stable • Population change • Births: fertility • Deaths: mortality • Migration • Population change = (births + immigration) – (deaths + emigration) • Crude birth rate: # live births/1000/year • Crude death rate: # deaths/1000/year
- 14. Women Having Fewer Babies but Not Few Enough to Stabilize the World’s Population • Fertility rate • number of children born to a woman during her lifetime • Replacement-level fertility rate • Average number of children a couple must have to replace themselves • 2.1 in developed countries • Up to 2.5 in developing countries • Total fertility rate (TFR) • Average number of children born to women in a population
- 15. Total fertility rate, 1955-2010 Fig. 6-5, p. 130
- 16. 2010 Rate of Population Increase Figure 11, Supplement 8
- 17. Figure 12, Supplement 8 Total Fertility Rate
- 18. Several Factors Affect Birth Rates and Fertility Rates • Factors that affect birth and fertility rates • Children as part of the labor force • Cost of raising and educating children • Availability of private and public pension • Urbanization • Educational and employment opportunities for women • Average age of a woman at birth of first child • Availability of legal abortions • Availability of reliable birth control methods • Religious beliefs, traditions, and cultural norms
- 19. Fig. 6-9, p. 133 Child Laborers in India
- 20. Several Factors Affect Death Rates (1) • Life expectancy • Average number of years a newborn infant can be expected to live • Infant mortality rate • Number of live births that die in first year • People are living longer • Increased food supply and distribution • Better nutrition • Medical advances • Improved sanitation
- 21. Several Factors Affect Death Rates (2) • High infant mortality rate is a measure of a country’s quality of life • U.S. is 54th in world for infant mortality rate • U.S. infant mortality rate high due to • Inadequate health care for poor women during pregnancy and their infants • Drug addiction among pregnant women • High birth rate among teenagers
- 22. Fig. 6-10, p. 134 Infant Mortality Rates, 1950-2010
- 23. Figure 13, Supplement 8 Infant Mortality Rates in 2010
- 24. Migration Affects an Area’s Population Size • Migration • The movement of people into (immigration) and out of (emigration) specific geographic areas • People migrate for many reasons i.e. • Economic improvement • Religious freedom • Political freedom • Wars • Environmental refugees
- 25. A Population’s Age Structure Helps Us Make Projections • Age structure • Numbers or percentages of males and females in young, middle, and older age groups in a population • Categories: • Pre-reproductive ages (0-14) • Reproductive ages (15-44) • Post-reproductive ages (45 and older)
- 26. Fig. 6-12, p. 136 Generalized Population Age-Structure Diagrams
- 27. Fig. 6-13, p. 136 Population Structure by Age and Sex in Developing and Developed Countries
- 29. Populations Made Up of Mostly Older People Can Decline Rapidly • Consequences of a large aging population • Slow decline • Manageable • Rapid decline • Severe economic problems • How pay for services for elderly • Proportionally fewer young people working • Labor shortages • Severe social problems
- 30. Fig. 6-15, p. 138 Some Problems with Rapid Population Decline
- 31. How Can We Slow Human Population Growth? • We can slow human population growth by reducing poverty, elevating the status of women, and encouraging family planning.
- 32. As Countries Develop, Their Populations Tend to Grow More Slowly • Demographic transition • As countries become industrialized and economically developed: • First death rates decline • Then birth rates decline • Takes place in 4 stages 1. Preindustrial 2.Transitional 3.Industrial 4.Postindustrial
- 33. Fig. 6-17, p. 140 Four Stages of the Demographic Transition
- 34. Fig. 6-18, p. 140 TFR in Bangladesh and U.S., 1800-2010
- 35. What’s Behind Population Growth • Three Factors • Fertility • Infant Mortality • Longevity • Animal Domestication and Agriculture • Provided for a few to feed many • Industrial Revolution • Growth of Cities and Infrastructure • Water • Energy • Transportation • Increased Productivity • Nutrition • Sanitation • Medicine
- 36. Human Population Growth and the Environment • Human Population - An Explosive Growth • Human Needs - Limited Resources • Our Natural Environment Under Attack • Roles of Technology and Engineering • An Uncertain Future
- 37. Environmental Impacts of population growth Resource Limits - Land (7) • Deforestation: Deforesting to acquire more arable land • Would run out in next century at current yields • Probably need to double yields
- 38. Resource Limits - Water (8) • In 1950 people used half of accessible water • Are now dependent on dams • Pollution loses 33% of potential water • Getting close to limits
- 39. Energy Consumption (9) • Energy growth very high last fifty years • Mostly hydrocarbon fuels • Nonrenewable resource consumption and climate change issues
- 40. Planet Earth is Impacted (12) • Ecological Footprints • United States - 5 hectares/person • Developing nations - 0.5 hectare/person • For everyone to live at today’s US footprint would require 3 planet Earths • Increasing affluence and population is damaging Earth’s essential ecology
- 41. Biodiversity is in Danger (13) • Humanity has spawned a species extinction to rival the 5 great extinctions of 65 - 440 million years ago • Recovery times from the great extinctions took 10’s of millions of years • Biodiversity is essential to life on Earth
- 42. Global Warming - A Good Example • Atmospheric CO2 is increasing, and creates greenhouse effect.(14) • 3-5°C rise predicted by computer models for this century would have major environmental impact. (15) • Observed change of 0.25-0.4°surface and 0.0- 0.2°C troposphere rise in last 20 years doesn’t agree with models and may or may not be due to CO2.(16) • Humans - 6 billion tons/year of CO2 (up 500% from 1950, and increasing) (17) • Other sources 200B tons/year • Total atmosphere load - 775B tons • Total earth load with oceans - 42,000B tons 0.6°C rise in last 100 years
- 43. Our ‘Commons’ are in Danger • Atmospheric pollution and climate change • Water pollution, including ground aquifers • Deforestation and loss of oxygenation • The oceans, coral reefs and their bounty • National parks, wildernesses and wetlands • Nonrenewable natural resource depletion • Fossil fuels, mineral ores, topsoil…..
- 44. Impacts Developed and Developing countries have different impacts most of the world lives in developing countries, but developed countries consume more resources ecological footprints and wealth gap Affluence Measure Impact using IPAT equation Impact= population x affluence x technology As a population grows resources need to be available to meet the needs of the people land use (housing and agriculture) Sanitation and health care Access to clean water
- 45. Solutions: Technology’s Roles • Detailed explicit information and understanding of what is occurring • Sensors, data processing, computers, models, predictions, communication, information…... • Alternate technologies that mitigate and eliminate deleterious effects • Energy, water, transportation, communication… • Sustainable Development
- 46. Engineers are vital • Developing and applying • the means by which to measure, analyze and predict future conditions • the technologies by which to mitigate and eliminate undesired effects • Describing, explaining and communicating • To policy makers • To the non-technical public • Creating the framework for a sustainable environment
- 47. More Solutions for slowing population growth • economic development • reduction of poverty • Education • family planning • reproductive health care • empowering women
- 48. 4 8 family planning helps couples choose how many children to have and when to have them educating men and women birth spacing, birth control, health care for women and infants the older a women is when she has her first child will decrease the total number of children reduces number of pregnancies and abortions (major decrease in TFR) lack of access to services hinders efforts
- 49. Problems with a growing population • “graying of a population” (Japan) • Characteristic of highly developed countries • Women choosing not to have children..pursue career instead • who will care for the elders? • income to provide for social services • economic impacts (smaller workforce) • some countries providing incentives to have more children (Europe) • may be balanced out with a large number of immigrants
- 50. Summary • Major increases are occurring in human population and affluence. • Major stresses result in our society, natural environment, and ecology. • Technology and engineering are central to the creation and the mitigation of problems. • Predicting the future is difficult (17). The next twenty five to fifty years will be decisive.
Editor's Notes
- #2: Figure 6.1: Hundreds of people crowd a street in China. Almost one of every five persons on the planet lives in China, and the country’s resource use per person is projected to grow rapidly as China becomes more modernized and wealthy.
- #6: Figure 1.18: Exponential growth: The J-shaped curve represents past exponential world population growth, with projections to 2100 showing possible population stabilization as the J-shaped curve of growth changes to an S-shaped curve. (This figure is not to scale.) (Data from the World Bank and United Nations, 2008; photo L. Yong/UNEP/Peter Arnold, Inc.)
- #8: Figure 6.3: Most of the world’s population growth between 1950 and 2010 took place in the world’s less-developed countries. This gap is projected to increase between 2010 and 2050. (Data from United Nations Population Division, The 2008 Revision and Population Reference Bureau, 2010 World Population Data Sheet)
- #9: 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)
- #11: Figure 6.A: This graph shows world population projections to 2050 from three different organizations: the UN, the U.S. Census Bureau, and IIASA. Note that the upper-most, middle, and lower-most curves of these five projections are all from the UN, each assuming a different level of fertility.
- #12: Figure 6.B: This list describes eight major ways in which we humans have altered natural systems to meet our growing population’s resource needs and wants.
- #16: 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)
- #20: Figure 6.9: These young girls are child laborers in the state of Rajasthan in India. They are weaving wool on looms to make carpets for export, and receive very little money for their work.
- #23: Figure 6.10: This graph tracks the infant mortality rates for the world’s more-developed countries and less-developed countries, 1950–2010, with projections to 2050 based on medium population projections. (Data from United Nations Population Division)
- #27: 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)
- #28: 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)
- #31: Figure 6.15: Rapid population decline can cause several problems. Question: Which three of these problems do you think are the most important?
- #34: 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?
- #35: Figure 6.18: This graph tracks demographic transition in terms of the average lifetime number of births per woman (TFR) in Bangladesh and in the United States, 1800–2010. Question: What role do you think economic development has played in the different paths that these two countries have taken toward making a demographic transition? (Data from Population Reference Bureau, World Population Data Sheet 2009 and 2010; Bangladesh: United Nations Demographic and Heath Surveys; United States: Ansley Coale and Melvin Zeinik and National Center for Health Statistics)