The Human Population

The Human Population The Environmental Implications of China’s

Growing Population

•China has 20% of the world’s population (1.3 billion)•Currently the largest emitter of CO2

•1970s started the 1 child per family policy•This has now been relaxed (Under the new policy (2013),

families could have two children if one parent, rather than both parents, was an only child.)

•Population may start to decline by 2040•Beginning to improve conditions•Other nations pose a risk

Earth’s Carrying Capacity• Growing populations of humans provides an increasing

supply of intellect that leads to increasing amounts of innovation.

• By employing creativity humans can alter Earth’s carrying capacity

• Food deficit vs. ongoing improvements!?

Scientists Disagree on Earth’s Carrying Capacity

•The following graphs show theoretical models of food supply and population size.

Why Scientists Disagree about the Carrying Capacity?

--Believe outgrown OR will eventually outgrow available

supply of resources such as food, water, timber, fuel, etc.

--Malthus= Human population growing exponentially but food

supply growing linearly Environmental Scientists still believe that we will reach our

carrying capacity= human population growth will decline

--Do not believe there is a carrying capacity for humans

--Growing population provides an increasing supply of intellect that

leads to increasing amounts of innovation

Inventions/technological advances increase carrying

capacity over time --Ex: Development of arrow made hunting more efficient

Population Growth•Until the Middle Ages, human populations were held in check by diseases, famines and wars, and thus grew very slowly.•It took all of human history until 1800 to reach 1 billion.•150 years to reach 3 billion•12 years to go from 5 to 6 billion•Human population tripled during the twentieth century.

•“Natural Population Control” = Disease, Famine, War

Factors that Drive Human Population Growth

Demography- the study of human populations and population trends.

Changes in Population SizeMigration (emigration & immigration)

FertilityLife ExpectancyAge Structure

Changes in Population Size

Immigration- the movement of people into a country

Emigration- the movement of people out of a country.

Net migration rate- the difference between immigration and emigration in a give year per 1,000 people in the country.

How do Populations change in size

Global Scale: Birth rate – death rate = growth rateb - d = r growth rate (r) can be + or –

Local Scale: movement from one region to anotherImmigration – # individuals entering a population

Emigration - # individuals leaving a populationr = (b – d) + (i – e)

Family Planning

•Regulation of the number or the spacing of offspring through the use of birth control.

•The more education, the less children people tend to have.

Ideal Family Size Is Culturally And Economically Dependent

Many factors increase our desire for children•Labor•Old Age Support•Status•Love

Other factors discourage reproduction•Cost (Monetary, Lifestyle)•Negative Status

Could we have a birth shortage?

Birth Reduction Pressures

In developing countries, higher income often means families can afford more children, thus fertility often increases.

In less-developed countries, adding another child to a family usually does not cost much, while in developed countries, raising an additional child can carry significant costs.

10 Factors affecting Birth rate and Fertility rate

1. Average level of education and affluence

2. Importance of children as a part of the labor force

3. Urban areas (with access to family planning)

4. Cost of raising and educating children

5. Education and employment opportunity for women

6. Infant mortality rate

7. Average age of marriage and 1st child

8. Availability of pension system

9. Availability of legal abortions

10. Birth control/religion

Life Expectancy

Life expectancy- the average number of years that an infant born in a particular year in a particular country can be expected to live, given the current average life

span and death rate of that country.

Life Expectancy

Infant mortality rate- the number of deaths of children under 1 year of age per 1,000 live births.

Child mortality rate- the number of deaths of children under age 5 per 1,000 live births.

• Predictor of health care, food supply, drinking water, sanitation, and prenatal care.

US: 6.6France and Sweden: 2.5, 3.6

Liberia: 99Bolivia: 50

Varies within each country as well.

Life Span and Life Expectancy

• Declining mortality is the primary cause of most population growth in last 300 years.

• Worldwide, average has risen from 40 to 65.5 over the past century.

• Greatest progress has been in developing countries.

• Largely due to curbing infant mortality

Aging and Disease

• Second largest killer to heart disease. • Tuberculosis and malaria were responsible

for the most amount of deaths. • HIV has taken its place.

AIDS and HIV

• Responsible for the for the greatest amount of human deaths.

• Affects humans in their reproductive years. • Most prominent in Africa.

Demographic Implications of Living Longer

• A population growing rapidly due to natural increase has more young people than a stationary population.

• Both rapidly and slowly growing countries can have a problem with dependency ratio.

• The number of non-working compared to working individuals in a population.

Age Structure

Age structure diagrams (population pyramids)-visual representations of age structure within a

country for males and females.

Age StructureFour general types:

• Pyramid- population w/ many young and high death rate (short average lifetime)

• Inverted pyramid- top heavy (Japan?)• Column- birth rate and death rate are low and a

high % of pop is elderly• Column w/ a bulge- event in the past caused a

high birth or death rate for some age group

Age Structure DiagramsPositive Growth Slow Growth Negative Growth/

Zero Growth

Pyramid Shape Vertical Edges Inverted Pyramid

The Demographic Transition

The theory of the demographic transition is the theory that as a country moves from a subsistence economy to

industrialization and increased affluence, it undergoes a predictable shift in population growth.

**Write in your notes sheet

under:What is it?**

Theory of Demographic Transition

Phase1 – Pre-Industrial –Before the industrial Revolution

Phase 2 – Transitional - IndiaPhase 3 – Industrial – US &

CanadaPhase 4 – Post Industrial –

UK, Germany, Russia, Italy, Japan

The Stages of the Demographic Transition

• Phase 1: Slow population growth because there are high birth rates and high death rates which offset each other.

• Phase 2: Rapid population growth because birth rates remain high but death rates decline due to better sanitation, clean drinking water, increased access to food and goods, and access to health care.

• Phase 3: Stable population growth as the economy and educational system improves and people have fewer children.

• Phase 4: Declining population growth because the relatively high level of affluence and economic develop encourage women to delay having children.

Population Size & Consumption Interact to Influence the Environment

• Population size: critical factor in the impact of humans on Earth

• Amount of resources each person uses is another critical factor

• Every human exacts a toll on the environment by eating, drinking, generating waste, and consuming products

• Population and economic development are not equally distributed around the world, THUS the human impact on natural resources is also unequally distributed

Developed vs. Developing

Developed countries- countries with relatively high levels of industrialization and income.

Developing countries- countries with relatively low levels of industrialization and income of less that $3 per person per day.

The relationship between economic development and population growth rate for

developing nations.

• Population disparity between rich and poor countries has accelerated in recent decades

• Shows the relationship b/t economic development & population growth rate for developing nations

• Developing Nations: grow rapidly

• Developed Nations: Growth has almost leveled off **Impoverished countries are

increasing their pop. more rapidly than affluent countries

The 12 Most Populous Countries in the World

• About 5.6 billion live in developing countries

• Only about 1.3 billion live in developed countries

• 9 out of 12 most populous nations on Earth are developing countries

Developing v. Developed Countries and Resources

• Although only 1/5 of the human pop. live in developed countries, those people consume more than ½ of the world’s energy and resources

• One person in a developed country may have 2 to 10 times the environmental impact of a person in a developing country

Sustainability

avoidance of the depletion of natural resources in order to maintain an

ecological balance

What Keeps Us Alive? Capital➢Solar Capital:without the sun there

would be no life.

➢Natural Resources:Air, water, soil,

minerals

Fig. 1-2, p. 7

What is an environmentally sustainable society?

Meets the basic needs of its people indefinitely without compromising future generations ability to meet those same

needs?

Resources➢Perpetual: renewed

continuously on a

human scale.

➢Renewable: can be

replenished fairly

quickly.

➢Non-renewable: exist

only in fixed quantities.

(once they are gone

they are gone.)

Fig. 1-6 p. 9

Renewable ResourcesCan be depleted or degraded.

Sustainable Yield: the highest rate at which a

renewable resource can be used without reducing its

supply.Example: over-farming the land

leading to soil erosion, clear-cutting forests.

Environmental Degradation: when we

exceed the natural replacement rate of the

resource.Example: groundwater depletion,

water pollution.

Non-Renewable ResourcesExist only in fixed quantities on earth.

➢Energy Resources: such as coal, oil and natural gas.

➢Metallic Resources:such as iron, copper, aluminum

➢Non-Metallic

Resources: Such as salt, clay, sand

Economic DepletionFig. 1-8 p. 11

When 80% is gone it may be too costly to get the last 20%.

Ecological Footprint

Fig. 1-7 p. 10

Measure of the biologically productive land and

water needed to support each person.

1 hectare = 100 acres or 10,000 square meters (about 100 football fields)

Refuse, Reduce, Reuse and RecycleRefuse: Don’t use some

productsReduce: Use less resourceReuse: To use the resource

more than once to conserve.

Recycle: collecting resource, processing it into

new products.

Ecological Footprints

• Provides a way to measure the effect of affluence on the

planet• A measure of human demand on

the Earth’s ecosystems

Ecological Footprints

Affluence - having a lot of wealth such as money, goods, or property.

Ecological Footprint• One person in a developed

country can have a greater impact than two or more people in a developing country

• EX) Person living in US has more than 18X the environmental impact of a person living in Haiti

•World average= 6.7 acres per capita

•US= 22 acres per capita

•China= 4.5 acres per capita

•Haiti= 1.2 acres per capita

The IPAT EquationTo estimate the impact of human lifestyles on Earth we

can use the IPAT equation:

Impact= Population X Affluence X Technology

IPAT Impact= Population X Affluence X Technology

• Hard to quantify the total environmental impact of the world:

• Some people live “green” or unintentionally (poverty)

• Some people consume large amounts of resources

• Estimates the impact of human lifestyles on Earth

• Representation of the three major factors that influence environmental impact

1) Population

• Straightforward effect on impact• When we compare two countries with

similar economic circumstances the one with more people is likely to have a large impact on the environment

2) Affluence • Does not have as simple a relationship to impact as population

does • One person in a developed country can have a greater impact

than two or more people in a developing country

• Ex) Family of four in the US that owns two large sport utility vehicles and lives in a spacious home with a lawn and a swimming pool uses much larger share of Earth’s resources than a Bangladeshi family of four living in a two-room apartment and traveling on bicycles and buses

• The more affluent a society or individual is, the higher the environmental impact

3) Technology • Can either degrade the environment or

create solutions to minimize our impact on the environment

• Examples• CFCs lead to ozone destruction • Hybrid Electric Cars helps reduce impact of

cars on environment • More?

• Now like to use “destructive technology” to differentiate it from beneficial

Local, Global, & Urban Impacts

• Impacts on the environment may occur locally, or they may be global in scale

• The scale of the impact depends on the economy and degree of development of a society

• EX) A person may create a local impact by using products created within the country’s borders, or the same person may create a global impact by using materials that are imported

The Impact of Affluence

• Gross domestic product (GDP)- the value of all products and services produced in a year in that country.

• GDP is made up of consumer spending, investments, government spending, and exports minus imports.

• A countries GDP often correlates with its pollution levels.

The Impact of Affluence

• At very low levels of per capita GDP, industrial activity is too low to produce much pollution

• The country uses very little fossil fuel and generates relatively little waste

• Many developing countries fit this pattern

The Impact of Affluence

• However, as GDP increases, a nation is able to afford to burn fossil fuels, which is relatively cheap fuel but a large emitter of pollution

• Country may also rely on rudimentary, inefficient equipment that emits large amount of pollutants

• At this point: Country emits pollution at the highest levels

The Impact of Affluence

• As GDP increases further, the country may reach a turning point

• Can afford to purchase equipment that burns fossil fuels more efficiently and cleanly

• People may be more willing to support this and expend resources

• Wealthier societies are also able to afford better policing and enforcement mechanisms

• USA and Western European countries fit this scenario today

The Impact of Affluence

• Some environmental scientists say increasing GDP for developing nations is the best way to save the environment • 1) Rising income generally correlates to

falling birth rates, and reducing population size should lead to a reduction in environmental impact

• 2) Wealthier countries can afford to make environmental improvements and increase their efficiency of resource use

In the News...

• Hard to quantify the total environmental impact of the world:

• Some people live “green” or unintentionally (poverty)

• Some people consume large amounts of resources

• Estimates the impact of human lifestyles on Earth

• Representation of the three major factors that influence environmental impact

The Impact of Affluence

• At very low levels of per capita GDP, industrial activity is too low to produce much pollution

• The country uses very little fossil fuel and generates relatively little waste

• Many developing countries fit this pattern

The Impact of Affluence

• However, as GDP increases, a nation is able to afford to burn fossil fuels, which is relatively cheap fuel but a large emitter of pollution

• Country may also rely on rudimentary, inefficient equipment that emits large amount of pollutants

• At this point: Country emits pollution at the highest levels

The Impact of Affluence

• As GDP increases further, the country may reach a turning point

• Can afford to purchase equipment that burns fossil fuels more efficiently and cleanly

• People may be more willing to support this and expend resources

• Wealthier societies are also able to afford better policing and enforcement mechanisms

• USA and Western European countries fit this scenario today

Low v. High Ecological Footprints

• A good example of differences between ecological footprints can be Bangladesh, Australia and United Arab Emirates.

• For example, Bangladesh has a very low ecological footprint which is around 0.6 ha/p. The reason why it is so low because of small population, Little affluence and low technological level. Basically these sum up a not completely developed nation.

• On the other hand Australia has 8.49 ha/p and United Arab Emirates 15.99 ha/p. The reason why these two countries have high footprint is because of high development rate, a lot of investment and good natural resources; such as, oil or uranium.

GDP affects directly the ecological footprint. Look at the table the x-axis is the GDP and Y-axis is the Ecological footprint. The higher the GDP is the

higher the ecological footprint is. This shows that ecological footprint depends on GDP and vice verse.