Human Population and Its Impact

Milton High SchoolAP Environmental Science

What is demography and why is it important?

The study of the vital statistics that affect population size.

- Size - Age Distribution - Density - Dispersion

Today about same pop. size

Tanzania has about 45% of its population under the age of 15 compared to Spain

with 15% of its population under the

age of 15

By 2050Tanzania will have 4% of its population 65 or

older and Spain will have 33% of its

population 65 or older

What problems will this cause for Spain?

Water well in India

August 25, 2011World Population United States Population 6,957,846,471 312,067,591

September 8, 2013World Population United States Population7,110,071,755 316,633,832

Commuter train in India Outhouse in Bangladesh

How long will it take for you to count 1 million dollars at 1 dollar per second for 8 hours per day?

How long will it take you to count 1 billion dollars at the same rate?

If someone asked you how big is a billion, what would you say?

Current world human population is about 7,110,075,000Do you think if every human on Earth was to hold hands they would be able to stretch around the Earth’s equator (about 24,900 miles)? Could we stretch to the Moon (238,857 miles)? How about stretching to the Sun (93 million miles)? Support your answer with math.

Is the world overpopulated?The world’s population is over

7 billion people

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.

Is most of the world’s population in developed or developing countries?

Nearly all future population growth will be in the World’s less developed countries

Can our Earth support more people?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, and personal freedom.)

Human Population Growth

1.2%This adds 80 million people a year.

World population growth rate

Population Growth Variables Crude Birth Rate (CBR) Crude Death Rate (CDR) Immigration Emigration Density Dependant Factors Density Independent Factors Cultural Practices Technology Revolutions

Factors Affecting Human Population Size•Births•Deaths•Migration

Crude Birth Rate – the number of births per 1,000 people in a population in a given year

Crude Death Rate: the total number of deaths per 1000 people. Usually it is measure per country. The crude death rate for the whole world is currently about 9.6 per 1000 per year (based on 62 million deaths in 2006, for a population of 6470 million).

Crude Birth Rate

Crude Death Rate

Total Fertility Rate (TFR) – the average number of children a woman typically has during her reproductive years.

Poverty affects population growth Develop Countries Growth Rate 0.1% Less Developed Countries Rate 1.15%

Population Growth Rate

The average annual percent change in the population, resulting from a surplus (or deficit) of births over deaths and the balance of migrants entering and leaving a country. The rate may be positive or negative. The growth rate is a factor in determining how great a burden would be imposed on a country by the changing needs of its people for infrastructure (e.g., schools, hospitals, housing, roads), resources (e.g., food, water, electricity), and jobs. Rapid population growth can be seen as threatening by neighboring countries.

https://www.cia.gov/library/publications/the-world-factbook/fields/2002.html

CIA World Factbook

Factors affecting fertility and births Infant mortality rate Average age at marriage Ability of Legal Abortions Availability of Reliable Birth Control Methods Religious beliefs, traditions, and cultural norms 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 Importance of young adults joining the military

How can family planning help? Birth Spacing Birth Control Health Care for Pregnant Women Health Care for Infants

Key Factors to Fewer Children Ensuring education Having jobs outside the home Living in societies where their rights are not suppressed

Two useful indicators of overall health of people in a country or region•Life expectancy•Infant mortality rate

Life Expectancy – the average number of years a newborn infant can expect to live

Infant Mortality Rate – the number of babies out of every 1,000 born who die before their first birthday

Why death rates have declined•Food supplies and distribution•Better nutrition•Medical advances in vaccines and

antibiotics•Improved sanitation•Safer water supplies

Infant mortality and female literacy

Age structure diagrams Shows the distribution of various age groups in a population.

A great deal of information about the population broken down by age and sex can be read from a population pyramid, and this can shed light on the extent of development and other aspects of the population.

Populations with a large proportion of its people in the pre-reproductive ages of 1-14 have a large

potential for rapid population growth

Teenagers and Pyramids The number of people under age 15 is the major factor determining a country’s future population growth.

Population pyramids can be used to find the number of economic dependents being supported in a particular population.

30% (1.9 billion) of people on the planet were under 15 years of age in 2004.

Economic Projections Who will need education

Who will need jobs

Who will determine markets

Who will affect elections

Who will need Medicare

How do human populations develop economically?

Demographic Transition ModelA model used to explain the process of shift from high birth rates and high death rates to low birth rates and low death rates as part of the economic development of a country from a pre-industrial to an industrialized economy.

Pre-industrial stage (Stage 1) High birth and death rates

Low medical care (natural meds)

Population limited by food availability (internal)

Transitional Stage (Stage 2) Increased food production Better medical care (esp. antibiotics) Improved sanitation (esp. drinking water) Decreased death rate Birth rate stays high (cultural norms) Period of rapid growth rate

Industrial Stage (Stage 3) Need for increased labor force Availability of education (esp. female) Delay in age of 1st reproduction Change in cultural norms Birth rates decline toward zero population growth (ZPG)

Post-industrial Stage (Stage 4) Industrial system no longer supports population High unemployment, poverty Food supplies diminish Environmental health declines (high disease) Social strife (disease, famine, war) Increased death rates and decreased birth rates

Problems associated with rapid population decline

Can threaten economic growth

Less government revenues with fewer workers

Less entrepreneurship and new business formation

Less likelihood for new technology development

Increasing public deficits to fund higher pension and healthcare

Why did China introduce a one-child policy in 1979?

•China had ¼ of World’s population•Occupied just 7% of World’s arable land•2/3 of population under the age of 30•Baby-boomers (1950 – 60) were entering

reproductive years•Introduced family planning policy

▫Economic reform▫Improvement of living standards

China’s One-child Family Policy•Restriction on family size• Late marriage and child-bearing•Spacing of children (cases in which 2nd child permitted)•Strictly enforced for urban residents and government

employees▫Exceptions

1st child has a disability Both parent work high-risk jobs (e.g. mining) Themselves from a one-child family Rural areas – 2nd child generally allowed if first child

was a girl

China’s One-child Policy – Systems of Rewards and Penalties• Incentives for compliance

▫Choice of jobs▫Retirement funds▫Preferential healthcare ▫Free homes and free water▫Children receive bonus points on middle school entrance exams

• Non-compliant penalties▫Substantial fines (3x the family annual income)▫Confiscation of belongings▫Dismissal from work▫Forced abortions

China’s One-child Policy - Successful or failure?

•Has decreased population by about 250 million•Has prevented 400 million births• Implementation more successful in urban areas than

rural areas•Concerns over workforce shortage•Concerns if young population will be able to care for

ageing population•Demographic imbalance

▫By 2020 could have 30 million unmarried men

Altering nature to meet our needs• Reduction of biodiversity• Increasing genetic resistance of pest species• Elimination of many natural predators• Introduction of invasive species• Unsustainable use of renewable resources• Interfering with earth’s biogeochemical cycles• Overuse of fossil fuels

http://www.youtube.com/watch?v=4B2xOvKFFz4