Human Populations Chapter 10

Core Case Study: Is the World Overpopulated? Much of the world’s population growth occurs in less-developed countries like China and India. Figure 9-1

Core Case Study: Is the World Overpopulated? The world’s population is projected to increase to 9.6 billion by 2050. The debate over interactions among population growth, economic growth, politics, and moral beliefs is one of the most important and controversial issues in environmental science.

Core Case Study: Is the World Overpopulated? Some argue that the planet has too many people. Some feel that the world can support billions of more people due to technological advances. There is a constant debate over the need to reduce population growth. Must consider moral, religious, cultural and personal freedoms.

HUMAN POPULATION GROWTH: A BRIEF HISTORY The human population has grown rapidly because of the expansion of agriculture and industrial production and lower death rates from improvements in hygiene and medicine. In 2006, the population of more-developed countries grew exponentially at 0.1% per year. Less-developed countries grew 15 times faster at 1.5% per year.

Where Are We Headed? We do not know how long we can continue increasing the earth’s carrying capacity for humans. 97% of growth in less-developed countries living in acute poverty. What is the optimum sustainable population of the earth based on the cultural carrying capacity?

Where Are We Headed? U.N. world population projection based on women having an average of 2.5 (high), 2.0 (medium), or 1.5 (low) children. Figure 9-2

Population Momentum Concept that a youthful population will continue to grow exponentially even if the fertility rate dropped to replacement level or below Human biotic potential Existing children still have to grow into adulthood and reproductive years Replacement level only refers to babies, not existing people

What is demography? Study of vital statistics about people Births Deaths Where they live Total population size

Current World Population Population Clock Vital Events (per time unit) The global population grows by: Nearly 2.4 persons per second Nearly 145 persons per minute Over 208,800 persons per day Over 7.62million persons per year Has actually gone down from this time last year https://www.cia.gov/library/publications/the-world-factbook/geos/xx.html

How Much is a Billion? 1,000 seconds = 16.7 minutes 1 million-s = 16,677 min = 11.6 days 1 billion-s = 11,574 days = 31.7 years 1,000 pennies = ~ 88 ounces = 5.5 pounds 1 million pennies = 5,500 pounds (~1-Suburban) 1 billion pennies = 2,750 tons (~2 Space Shuttles)

Impacts of Population Growth Hunger Disease Economic effects Resource use Habitat destruction

Human Population Outline Factors Affecting Human Population Size Population Age Structure Crude birth and death rates Carrying Capacity

Human Population Dynamics There are just three sources of change in population size — Fertility: Number of children born to a woman during her lifetime Mortality: “Natural decrease" refers to population decline resulting from more deaths than births Migration: Net migration is the number of immigrants minus emigrants

FACTORS AFFECTING HUMAN POPULATION SIZE Population increases because of births and immigration and decreases through deaths and emigration. Instead of using raw numbers, crude birth rates and crude death rates are used (based on total number of births or deaths per 1,000 people in a population).

Rates of Global Pop. Change use: International Data Base http://www Rates of Global Pop. Change use: International Data Base http://www.census.gov/ipc/www/idb/ then Online Demographic Aggregation CBR (crude birth rate) = # births / 1000 population 1990: 24 now: 18.6 (↓) (CIA World Fact book) CDR (crude death rate) = # deaths / 1000 population 1990: 9 now: 7.8 (↓) (CIA World Fact book) Natural Growth Rate = (b – d) 1990: 1.5% now: 1.08% (↓) (CIA World Fact book) https://www.cia.gov/library/publications/the-world-factbook/geos/xx.html

Annual Population Change Annual rate of natural population change = {(Birth rate – Death rate)/1000 persons} x 100 = (Birth rate – Death rate)/10 Exponential growth has not disappeared but is occurring at a slower rate Exponential growth is five times faster in less-developed countries than in more-developed countries

World Population Growth MI L I O NS

World Population Growth Most of the world’s population growth between 1950 and 2010 took place in the world’s less-developed countries. Source: United Nations, World Population Prospects: The 2006 Revision (2007).

Changes in Population Growth Population growth rate is declining world-wide

Changes in Population Growth Country Pop (millions) Pop 2025 China 1373 1393 India 1280 1523 US 322 362 Indonesia 255 280 Brazil 205 220 Pakistan 189 234 Nigeria 182 258 Bangladesh 159 Russia 146 136 Japan 127 123 Mexico 121 135 The world’s 10 most populous countries in 2015 with projections in 2030.

FACTORS AFFECTING HUMAN POPULATION SIZE Average crude death and birth rates for various groupings of countries in 2006. CIA - The World Factbook Figure 9-3

Projected Populations 2050 Projected population by 2050, in millions By 2050, India is expected to become the world's most populous nation. The U.S. should remain third. World Population Prospects, the 2008 Revision. United Nations Department of Economic and Social Affairs (DESA), Population Division, New York

The Rule of 70 How long does it take to double the number of people on the planet? {70/percentage growth rate} = doubling time in years In 2012, the world’s population grew by an estimated amount of 1.096%. If that rate continues, the earth’s population will double in about 63.9 years (70/1.096 = 63.9 years)

Projected US Population Growth With births exceeding deaths by nearly two to one, the U.S. population grows by almost 2.5 million each year, or 0.71 percent per year (2013). As things now stand, we are headed for 400 million Americans by 2050. https://www.census.gov/population/projections/data/national/2012/summarytables.html

Overall, the world population is growing at a rate of about 1 Overall, the world population is growing at a rate of about 1.1%; if this rate continues, the population will double in about 64 years. Unabated, such a rate would lead to a point about 2000 years hence when the mass of humanity would weigh more, and be larger, than the Earth. But, the growth rate is decreasing

World Population Density Map Population density map of the world showing not only countries but also many subdivisions (regions, states, provinces).  http://www.worldometers.info/world-population/

Declining Fertility Rates: Fewer Babies per Woman The average number of children that a woman bears has dropped sharply. This decline is not low enough to stabilize the world’s population in the near future. Replacement-level fertility: the number of children a couple must bear to replace themselves. Total fertility rate (TFR): the average number of children a woman has during her reproductive years.

Declining Fertility Rates: Fewer Babies per Women The replacement level to sustain a population is 2.1 children. In 2015, the average global Total Fertility Rate was 2.42 children per woman. 1.7 in more-developed countries (down from 2.5 in 1950). 2.6 in less-developed countries (down from 6.5 in 1950). http://www.census.gov/ipc/www/idb/informationGateway.php

Fertility Rates Fertility Rates Have Fallen in Every Major World Region, But Are Still Highest in Sub-Saharan Africa. Source: United Nations, World Population Prospects: The 2006 Revision (2007); and Carl Haub, 2007 World Population Data Sheet.

Case Study: U.S. Immigration Since 1820, the U.S. has admitted almost twice as many immigrants and refugees as all other countries combined. Figure 9-8

Case Study: Fertility and Birth Rates in the United States In 2014, the total fertility rate in the United States was estimated at 1.9(↓) Figure 9-5

Case Study: Fertility and Birth Rates in the United States The baby bust that followed the baby boom was largely due to delayed marriage, contraception, and abortion. Figure 9-6

What Factors Affect Birth Rates and Fertility Rates? Importance of children as part of the labor force Cost of raising and educating children Availability of private and public pension systems Urbanization Educational and employment opportunities available for women Infant mortality rate Average age at which women have their first child Availability of legal abortions Availability of reliable birth control methods

What Factors Affect Death Rates? Fewer infants die when a country has: An increase in food supplies and distribution Better nutrition Medical advances (antibiotics and vaccines) Improved sanitation Safer water supplies Two indicators of overall health of people in a country: Life expectancy Infant mortality rate (number of babies out of every 1000 born who die before their first birthday) Indicative of society’s quality of life because it reflects a country’s general level of nutrition and health care.

POPULATION AGE STRUCTURE The number of people in young, middle, and older age groups determines how fast populations grow or decline. The number of people younger than age 15 is the major factor determining a country’s population growth. Changes in the distribution of a country’s age groups have long-lasting economic and social impacts.

POPULATION AGE STRUCTURE Populations with a large proportion of its people in the preproductive ages 1-14 have a large potential for rapid population growth. Figure 9-9

POPULATION AGE STRUCTURE 32% of the people in less-developed countries were under 15 years old in 2006 versus only 17% in more-developed countries. Figure 9-10

POPULATION AGE STRUCTURE Today, baby boomers make up nearly half of all adult Americans and dominate the population’s demand for goods and services. Figure 9-11

Population Pyramids Population Pyramids

POPULATION AGE STRUCTURE Age structure predictions based on a medium fertility projection. The cost of an aging population will strain the global economy. Figure 9-12

POPULATION AGE STRUCTURE Some problems with rapid population decline. Which of these problems do you believe are the most important? Figure 9-13

Demographic Transition Movement of a nation from high population growth to low population as it develops economically Transition as a result of four stages Stage 1—Birth and death rates are both high Stage 2—Death rates fall; birth rates remain high; growth rate rises Stage 3—Birth rates fall as standard of living rises; growth rate falls Stage 4—Growth rate continues to fall to zero or to a negative rate

SOLUTIONS: INFLUENCING POPULATION SIZE Generalized model of demographic transition. Some less-developed countries may have difficulty making the demographic transition. Figure 9-14

SOLUTIONS: INFLUENCING POPULATION SIZE Family planning has been a major factor in reducing the number of births and abortions throughout most of the world. Women tend to have fewer children if they are: Educated. Hold a paying job outside the home. Do not have their human rights suppressed.

Empowering women to reduce births Women tend to have fewer, and healthier children when: they have access to education and paying jobs outside home their society doesn’t suppress women’s rights

SLOWING POPULATION GROWTH IN INDIA AND CHINA For more than five decades, India has tried to control its population growth with only modest success. Since 1970, China has used a government-enforced program to cut its birth rate in half and sharply reduce its fertility rate.

Illiteracy (% of adults) 47% 17% 36% Population under age 15 (%) 20% Percentage of world population 17% India 20% China 1.1 billion Population 1.3 billion Population (2050) (estimated) 1.4 billion 1.6 billion Illiteracy (% of adults) 47% 17% 36% Population under age 15 (%) 20% 1.6% Population growth rate (%) 0.6% 2.9 children per women (down from 5.3 in 1970) Total fertility rate 1.6 children per women (down from 5.7 in 1972) 58 Infant mortality rate 27 Figure 9.15 Global connection: basic demographic data for India and China in 2006. (Data from United Nations and Population Reference Bureau) 62 years Life expectancy 70 years Percentage living below $2 per day 80 47 $3,120 GDP PPP per capita $5,890 Fig. 9-15, p. 186

Case Studies - India Family planning efforts began in 1952; fertility rate has declined from 5.3 to 2.5 but population growth is still exponential at 1.3% Disappointing results due to: poor planning bureaucratic inefficiency low status of women extreme poverty lack of administrative & financial support

Case Study - China Nation with best-known population control program Reasons Chinese government initiated population control measures: Freshwater and food at a premium for nation’s population Country experiencing population momentum Government perks / coercive measures for citizen compliance: Free education and health care Increased personal and family incomes Increased legal marrying age for women Contraceptives, abortions, and sterilizations free of charge Preferential housing and retirement income

Case Studies - China Family planning efforts began in 1970; TFR fell from 5.7 to 1.5 currently; infant mortality and illiteracy rates 1/3 to 1/2 of India’s rates Population control program is extensive, intrusive and strict: postpone childbearing only one child/family -->benefits effective because China is communist

China’s Family Planning Program Currently, China’s TFR is 1.6 children per woman. China has moved 300 million people out of poverty. Problems: Strong male preference leads to gender imbalance. Average population age is increasing. Not enough resources to support population.

HUMAN ASPECTS ON NATURAL SYSTEMS We have used technology to alter much of the rest of nature in ways that threaten the survival of many other species and could reduce the quality of life for our own species. Figure 9-17