Human Population Growth and Urbanization: Factors, Trends, and Solutions, Slides of Ecology and Environment

Download Human Population Growth and Urbanization: Factors, Trends, and Solutions and more Slides Ecology and Environment in PDF only on Docsity! The Human Population and Urbanization Chapter 6 Docsity.com Human population growth continues but it is unevenly distributed • For most of history, the human population grew slowly, but has been growing exponentially for the past 200 years. Reasons for this increase in growth rate include: – Humans have expanded into almost all of the planet’s climate zones and habitats. – The emergence of early and modern agriculture allowed us to grow more food for each unit of land area farmed. – Death rates dropped sharply because of improved sanitation and health care. Docsity.com WHAT FACTORS INFLUENCE THE SIZE OF THE HUMAN POPULATION? Section 6-2 Docsity.com The human population can grow, decline, or remain fairly stable • Birth rate, or crude birth rate, is the number of live births per 1,000 people in a population in a given year. • Death rate, or crude death rate, is the number of deaths per 1,000 people in a population in a given year. • Population change of an area = (births + immigration) - (deaths + emigration) Docsity.com Women are having fewer babies but not few enough to stabilize the world’s population • The total fertility rate (TFR) is the average number of children born to women in a population during their reproductive years. • Between 1955 and 2011, the average global lifetime number of births of live babies per woman dropped from 5 to 2.5. • A TFR of 2.1 will eventually halt the world’s population growth. Docsity.com Several factors affect birth rates and fertility rates – The educational and employment opportunities available for women. – The average age at marriage. – The availability of legal abortions. – The availability of reliable birth control methods. – Religious beliefs, traditions, and cultural norms. Docsity.com Several factors affect death rates • People started living longer and fewer infants died because of increased food supplies and distribution, better nutrition, medical advances, improved sanitation, life expectancy, married women working, and safer water supplies. • Two useful indicators of the overall health of people in a country or region are life expectancy and infant mortality rate – The average global life expectancy increased from 48 years in 1955 to 69 years in 2011. Between 1900 and 2011, the average global life expectancy in the United States increased from 47 years to 78 years. Docsity.com Several factors affect death rates – Infant mortality is a measure of a society’s quality of life because it reflects the general level of nutrition and health care. A high infant mortality rate can results from insufficient food (undernutrition), poor nutrition (malnutrition), and a high incidence of infectious disease, which is exacerbated by under- or malnutrition. – While infant mortality rates in more-developed and less- developed countries have declined dramatically since 1965, more than 4 million infants die during their first year of life. Docsity.com CASE STUDY: The United States: A Nation of Immigrants • Since 1820, the United States has admitted almost twice as many immigrants and refugees as all other countries combined. • Legal and illegal immigration account for about 36% of the country’s annual population growth. • Between 1820 and 1960, most legal immigrants to the United States came from Europe. Since 1960, most have come from Latin America and Asia. Hispanics are projected to make up 30% of the U.S. population by 2050. Docsity.com CASE STUDY: The United States: A Nation of Immigrants • There is controversy over reducing legal immigration to the U.S. – Proponents of reducing immigration say it would help stabilize population size and reduce the country’s enormous environmental impact. – Those against say it would diminish the role of the U.S. as a land of opportunity and take away from cultural diversity and innovation. Most immigrants and their descendants start new businesses and create jobs. Many immigrants take menial and low-paying jobs that most other Americans shun. Docsity.com CASE STUDY: The United States: A Nation of Immigrants • There were an estimated 11 million illegal immigrants in the United States in 2011. There is controversy over what to do about illegal immigration. – Some want to deport all illegal immigrants. – Others want to set up programs that allow illegal immigrants to remain in the country as long as they are working towards citizenship. Docsity.com A population’s age structure helps us to make projections • Demographic momentum is rapid population growth in a country that has a large percentage of people younger than 15, and happens when a large number of girls enter their prime reproductive years. • 1.8 billion people will move into their reproductive years by 2025. • Most future human population growth will take place in less- developed countries due to their population age structure. • The global population of seniors (age 65 and older) is increasing due to declining birth rates and medical advances that have extended life spans. Docsity.com CASE STUDY: The American baby boom • Added 79 million people to the U.S. population 1946-1964. • The large numbers of baby boomers have strongly influenced the U.S. economy. First they created a youth market and are now creating the late middle age and senior markets. • As the baby boomers turn 65, the number of seniors will grow sharply through 2030. This process has been called the graying of America. • As the number of working adults declines in proportion to the number of seniors, so will the tax revenues necessary for supporting the growing senior population. Docsity.com Populations made up mostly of older people can decline rapidly • Japan has the world’s highest % of elderly people and the world’s lowest % of young people. – Due to its discouragement of immigration, it may face a bleak economic future. • The average age of China’s population is increasing at one of the fastest rates ever recorded. This could lead to a declining work force, higher wages for workers, limited funds for supporting continued economic development, and fewer children and grandchildren to care for the growing number of elderly people. Docsity.com Promote economic development • As countries become industrialized and economically developed, their populations tend to grow more slowly. This demographic transition has four phases: – Preindustrial – Transitional – Industrial – Postindustrial Docsity.com Promote economic development • Less-developed countries may transition to slower growth if modern technology can raise per capita incomes by bringing economic development and family planning. • Rapid population growth, extreme poverty, and increasing environmental degradation in some low-income less-developed countries—especially in Africa—could leave these countries stuck in stage 2 of the demographic transition. Docsity.com Empowering women can slow population growth • Women tend to have fewer children if they are educated, have the ability to control their own fertility, hold a paying job outside the home, and live in societies that do not suppress their rights. • Women account for 66% of all hours worked but receive only 10% of the world’s income and own just 2% of the world’s land. • Women make up 70% of the world’s poor and 64% of its 800 million illiterate adults. • Poor women who cannot read often have an average of 5–7 children, compared to 2 or fewer children in societies where almost all women can read. Docsity.com CASE STUDY: Slowing Population Growth in India • For over 50 years, India has tried to control its population growth with only modest success. • Two factors help account for larger families in India. – Most poor couples believe they need several children to work and care for them in old age. – The strong cultural preference for male children means that some couples keep having children until they produce one or more boys. • The result: even though 9/10 Indian couples have access to at least one modern birth control method, only 48% actually use one. Docsity.com Scientists see three important urban trends • An increasing percentage of the world’s people live in urban areas. • Urban areas grow in two ways—by natural increase due to births and by immigration, mostly from rural areas. • Three major trends in urban population dynamics have emerged: – The proportion of the global population living in urban areas increased from 2% in 1850 to 50% today, and is projected to be 70% by 2050. Docsity.com Scientists see three important urban trends – The numbers and sizes of urban areas are mushrooming. We now have cities with 10 million or more people (megacities or megalopolises) and will soon have hypercities with more than 20 million people. Megacities and hypercities are merging into megaregions that can stretch across entire countries. – Poverty is becoming increasingly urbanized, mostly in less-developed countries. An estimated 1 billion people in less-developed countries live in urban slums and shantytowns. Docsity.com Urban sprawl gobbles up the countryside • Urban sprawl, or the growth of low-density development on the edges of cities and towns, is eliminating surrounding agricultural and wild lands. • Urban sprawl is the product of affordable land, automobiles, relatively cheap gasoline, and poor urban planning. Docsity.com Urban sprawl gobbles up the countryside • Urban sprawl has caused or contributed to a number of environmental problems. – People are forced to drive everywhere, resulting in more emission of greenhouse gases and air pollution. – Sprawl has decreased energy efficiency, increased traffic congestion, and destroyed prime cropland, forests, and wetlands. – Sprawl has led to the economic deaths of many central cities as people and businesses move out. Docsity.com Urbanization has advantages • Cities are centers of industry, commerce, transportation, innovation, education, technological advances, and jobs. • Urban residents in many parts of the world tend to live longer than do rural residents, and have lower infant mortality and fertility rates. • Cities provide better access to medical care, family planning, education, and social services. • Recycling is more economically feasible. • Concentrating people in cities helps to preserve biodiversity. • Central cities can save energy if residents rely more on energy efficient mass transportation, walking, and bicycling. Docsity.com Urbanization has disadvantages – Destroying or degraded large areas of wetlands that have served as natural sponges to help absorb excess storm water. – Flooding as sea levels rise because of projected climate. • Cities in arid areas that depend on water bodies fed by mountaintop glaciers will face water shortages if global warming melts the glaciers. Docsity.com Cities tend to concentrate pollution and health problems • Cities produce most of the world’s air pollution, water pollution, and solid and hazardous wastes. • High population densities can increase the spread of infectious diseases, especially if adequate drinking water and sewage systems are not available. Docsity.com Cities affect local climates • Cities tend to be warmer, rainier, foggier, and cloudier. • Heat generated by cars, factories, furnaces, lights, air conditioners, and heat-absorbing dark roofs and streets creates an urban heat island surrounded by cooler suburban and rural areas. • The artificial light created by cities affects some plant and animal species. Docsity.com CASE STUDY: Mexico City • The severity of air pollution has been reduced by banning cars in its central zone, requiring air pollution controls on newer cars, phasing out leaded gasoline, and encouraging purchase of buses, taxis, and delivery truck that produce fewer emissions. The city also bought land for use as green space and planted more than 25 million trees to help absorb pollutants. Docsity.com Cities can grow outward or upward • Most people living in compact cities such as Hong Kong, China, and Tokyo, Japan, get around by walking, biking, or using mass transit such as rail or buses. • In countries such as the United States, Canada and Australia, plentiful land and networks of highways have produced dispersed cities whose residents depend on motor vehicles for most travel. Docsity.com Cities can grow outward or upward • Largely because of urban sprawl, all Americans combined drive about the same distance each year as the total distance driven by all other drivers in the world, and in the process use about 43% of the world’s gasoline. Docsity.com Reducing automobile use is not easy, but it can be done • A user-pays approach makes drivers pay directly for most of the environmental and health costs caused by their automobile use. – An example of full-cost pricing is a tax on gasoline that covers the estimated harmful costs of driving. – Gasoline revenues could be used to help finance alternatives to cars. – Taxing gasoline heavily would be difficult in the U.S. for several reasons. • Strong opposition from the public, and from transportation-related industries. • The dispersed nature of most U.S. urban areas. • Lack of fast, efficient, reliable, affordable mass transit options. Docsity.com Reducing automobile use is not easy, but it can be done • Raise parking fees and charge tolls on roads, tunnels, and bridges leading into cities, especially during peak traffic times. • Some cities promote car-sharing networks, which bill members monthly for the time they use a car and the distance they travel, and can decrease car ownership. Docsity.com Some cities promote alternatives to cars • The following are alternatives to cars, each with its own advantages and disadvantages: – Bicycles – Mass-transit rail systems in urban areas – Bus systems in urban areas – High-speed rail systems between urban areas (bullet trains) Docsity.com CASE STUDY: The new urban village of Vauban • Vauban is a suburb outside the city of Freiberg, Germany that is virtually free of cars. • Street parking, driveways, and garages are generally forbidden in the village. A parking space in a city garage costs $40,000. • Homes are within easy walking distance of trains, stores, banks, restaurants, and schools. There are numerous bike paths and a car-sharing club. Mass transit allows residents to work or shop in the city of Freiburg. • There are no single-family homes, only energy-efficient row houses that use passive solar energy. Docsity.com CASE STUDY: The new urban village of Vauban • An ecocity emphasizes the following goals: – Use solar and other locally available, renewable energy resources and design buildings to be heated and cooled as much as possible by nature. – Build and redesign cities for people, not cars. – Reduce the waste of matter and energy. – Prevent pollution. – Reuse, recycle, and compost 60–85% of all municipal solid waste. – Protect and encourage biodiversity by preserving undeveloped land and protecting and restoring natural systems and wetlands in and around cities. – Promote urban gardens and farmers markets. – Use zoning and other tools to keep urban sprawl at environmentally sustainable levels. Docsity.com CASE STUDY: The new urban village of Vauban • Current examples of ecocities include Curitiba, Brazil; Bogotá, Colombia; Waitakere City, New Zealand; Stockholm, Sweden; Helsinki, Finland; Leicester, England; Neerlands, the Netherlands; and in the United States, Portland, Oregon; Davis, California; Olympia, Washington; and Chattanooga, Tennessee Docsity.com CASE STUDY: The ecocity concept in Curitiba, Brazil • The city transformed flood-prone areas along its six rivers into a series of interconnected parks. • Curitiba recycles roughly 70% of its paper and 60% of its metal, glass, and plastic. Recovered materials are sold mostly to the city’s more than 500 major industries, which must meet strict pollution standards. • The poor receive free medical and dental care, child care, and job training, and 40 feeding centers are available for street children. • About 95% of Curitiba’s citizens can read and write and 83% of its adults have at least a high school education. All school children study ecology. Docsity.com Three big ideas • The human population is increasing rapidly and may soon bump up against environmental limits. • We can slow human population growth by reducing poverty, encouraging family planning, and elevating the status of women. • Most urban areas are unsustainable, but they can be made more sustainable and livable within your lifetime. Docsity.com