Human population growth

Topic 8

MEDC and LEDC

MEDCMore economically developed country

LEDCLess economically developed country

1. Most countries in Europe and North

America, Israel, and Japan

2. Industrialized nations with high

GDPs

3. Population is relatively rich

4. Individuals are unlikely to starve

through poverty

5. Relatively high level of resource

use per capita (per person)

6. Relatively low pop. Growth rates

largely due to low CBR but rising

CDRs

7. Have very high carbon and

ecological footprint

1. Most countries in sub-Saharan

Africa. Large areas of Asia and

South America

2. Less industrialized or have hardly

any industry at all

3. May have raw materials (natural

capital) but this tends to be

exported and processed in MEDCs

4. Population has a lower GDP and

higher poverty rates

5. More people are poor with low

standards of living

6. High pop. Growth rates largely due

to rapidly falling CDRs

7. Have lower carbon and ecological

footprint

Population growth

• Population size, for any species, is

affected by two inputs and two outputs,

which are influenced by a number of

different factors.

Calculating Population ChangeBirths, deaths, and net migrations

determine the numbers of individuals in a

population

LEDCs and MEDCs

• Human Development Index (HDI) is a

measure of “well being” of a country.

• It combines measures of both health (life

expectancy), wealth (gross domestic

product (GDP) per capita, and education

into one value

• It is used to rank countries

Time

# of ind

Lag Phase

Exponential

Growth phase

Transitional phase

(linear growth phase)

Plateau phase

(stationary growth)

Time

# of ind

Exponential

Growth phase

Population increases

exponentially, a period of

no constraints on growth.

“Unlimited” resources and no

accumulation of waste products.

High natality and low mortality.

Time

# of ind

Transitional phase

(linear growth phase)

Natality decreases, but exceeds

rising mortality, population still

growing but slowing down.

Developing shortage of resources,

waste products accumulating.

Time

# of ind

Plateau phase

(stationary growth)

Natality and mortality rates are

equal, so population size is

maintained constant.

Nutrient supply and waste products

do not support any growth in

numbers.

According to the United Nations Population

Fund global population reached 7 billion on

Monday, October 31st, 2011

What is the world population now?

http://www.worldometers.info/world-population/

Recent demographic change

• Total population and the rate of population growth are much higher in

LEDC’s compared to MEDC’s

• In 1960’s population growth in LEDC’s peaked at 2.4% a year

• By the mid 1990’s the rate of global population was down to 1.8%

• By 2011 it was 1.2%

• Africa is an exception growth is still at 2.5%

India and China make up 37% of the world’s population

How to determine crude birth

rates

• Determined by taking the number of live

births in one year in a country, dividing it

by the country’s population and

multiplying the number by 1000

Birth rates

• The number of births per year divided by the total population.

b = total births/total population

*the crude birth rate is usually stated as the number of births per 1000 individuals.

Birth rates, an example

• If the total population of mice in a forest is 1,000,000 and 5,000 mice were born in a one year time period the birthrate would be

5,000/1,000,000 = 0.005

0.005 X 100 = 0.5%

• The crude birth rate is what is usually reported which would be

0.005 X 10005 out of 1000 Confusing I know!

How to determine crude death

rates

• Determined by taking the number of

deaths in a country in one year, and

dividing it by the country’s population

and multiplying the number by 1000

Death rates

• The number of deaths per year divided by the

total population.

d = total deaths/total population

• The crude death rate is usually stated as the

number of deaths per 1000 individuals

Death rates, an example

• So for the same population of mice in a forest (1,000,000) there were a total of 2,500 deaths…so

2,500/1,000,000 = 0.0025 or 0.25%

• The crude death rate reported would be 2.5 out of 1000 (2.5/1000)

• If the birth rate of a country is 15 per thousand, this means

on average for every thousand people in this country 15

will be born.

• If the death rate is 10 per 1000, this means that 10 will die

for every 1000

• Rate of natural change – the difference between the birth

rate and death rate

• In this case it would be 5 per 1000

• Natural change can be positive (natural increase) or

negative (natural decrease)

• If birth rate is lower than the death rate then it is a natural

decrease

Population Doubling Time

• Doubling Time of a population is the number of years

it would take a population to double its size at its

current growth rate.

• Knowing the doubling times of populations is useful in

making international comparisons or variations within

countries.

• Population doubling makes people consider the

impact of population growth on resources and the

environment in general.

Population Doubling Time

Calculation doubling times

• Doubling time is determined by dividing 70 by the growth

rate.

• The number 70 comes from the natural log of 2, which is 70

• Example:

A country in 2010 with a population of 33 million had a

population growth rate of 0.9%

Population doubling time:

70/0.9 = 77.7 years

So, in 2087 if growth rate maintained, the country will have

doubled it pop. From 33 million to 66 million

Pop. Declining in

Ger. and Italy

• Total Fertility Rate-is the average

number of children each woman has

over her life time

• Differences between CBR and fertility

rate

• Fertility rate - is the number of births per

thousand women of childbearing age

• CBR – is the number of births per

thousand of total population.

Give out handouts

Demographic Transition

Model

Demographic transition model

• This model describes the pattern of

decline in mortality and fertility of a

country as a result of economic and

social development.

• It is described as a five-stage population

model.

•

The Classic Stages of

Demographic Transition

Time

Stage 1 Stage 2 Stage 3 Stage 4

Natural

increase

Birth rate

Death rate

Note: Natural increase is produced from the excess of births over deaths.

Lesson Plan: The Demographic Transition, Activity One

• Demographic transition- broad generalization about

population growth since the middle of the 18th century

• No country as a whole retains the characteristics of stage 1.

This only applies to the most remote societies on Earth.

• All MEDC’s are stage 4 or 5

• The poorest of LEDC’s are in stage 2 (Niger, Bolivia)

• Most LEDC’s with advanced social and economics are in stage

3. (Brazil, China, India)

• NICs (Newly industrialized countries) such as south Korea and

Taiwan are in stage 4

Stage 1

The high stationary stage

• Pre-industrial society

• High birth rate due to no birth control.

• High infant mortality rates.

• Cultural factors and agricultural society encourage

large families.

• High death rates due to disease, famine, poor

hygiene, and little medicine.

• Fluctuating population growth, overall no growth.

Stage 1

Aerial photo of

uncontacted

tribe in Brazil.

Photo courtesy

of the

Government of

Brazil.

Aerial photo of

uncontacted

tribe in Brazil.

Photo courtesy

of the

Government of

Brazil.

Stage 2

The early expanding stage

• LEDC

• Death rate drops as sanitation and food improve.

• Disease is reduced so lifespan increases.

• High population under the age of 15

• Birth rate is still high so population expands rapidly

and child mortality falls due to improved medicine.

• High growth rate.

Stage 2

Stage 3

The late expanding stage

• Wealthier LEDC

• As a country becomes more developed, birth rates

will also fall due to access to contraception,

improved healthcare, education, emancipation of

women.

• Increased mechanization reduces need for

workers.

• Desire for material goods increases.

• Infant death rates decrease.

• Smaller families.

• Growth begins to level off.

Stage 3

Stage 4

The low stationary stage

• MEDC

• Low birth and death rates.

• Industrialized countries.

• Stable population sizes.

• Life expectancy increases

Stage 3Stage 4

Stage 5

The natural decrease stage

• MEDC

• Population may not be replaced as fertility

is low.

• Problems of aging workforce put pressure

on economy.

• Birth rate may have fallen below death rate

resulting in natural decrease

Stage 5

Age/sex pyramids

• Age/sex pyramids are a graphic

representation of the age and gender

structure of a population.

• The pyramids are a snapshot in time but

can give a great deal of information

about the demographics of the

population.

How to construct a pyramid

• Calculate the percentage of the population that falls into each age category, and separate by gender.

• Take the number of individuals that fall into the age/sex category, divide by the total population and multiply by 100.

Analyze and

interpret the

pyramid

Analyze

• There is a wide base

• Decrease in width as

age increases

Interpret

• extremely high fertility rates.

• indicates relatively high

mortality rates

• The wide base reflects

extremely high fertility

rates.

• Birth rates are 48 per

1000

• Decrease in width

indicates relatively high

mortality rates

• Death rate 12 per 1000

• Infant mortality rate very

high 88 per 1000

• Life expectancy is 55

• 49% of pop. Under the

age of 15

• Stage 2

Analyze Interpret

• Lower fertility rates by

narrow band compared to

the middle age band

• 13 per 1000 births

• Decline in mortality by

each narrowing band

• Greater life expectancy

• Life expectancy is 80

• 9 per 1000 death

• Stage 4

What pyramids say about the population

Expanding pyramids

• This population is very bottom heavy.

• The birth rates are high.

• Most of the population is young, causing competition for jobs and resources.

Still expanding but the birth rate is dropping and growth rate is slowing.

Chimney shapes indicate that birth and

death rates are both low, population

growth is close to zero.

Contracting pyramid indicates a declining growth rate.

This can cause a financial burden on the working age

individuals to support an aging population.

Environmental FactorsEnvironmental factors may be

categorized according to how much

population density influences their effect

on population growth:

Density independent factors have a

controlling effect on population size and

growth, regardless of the population

density.

Density dependent factors have an

increasing effect on population growth as

the density of the population increases.

Severe fires can result in high mortality

Humans often live at high density

Density Dependent FactorsDensity dependent factors exert a greater

effect on population growth at higher

population densities.

At high densities, individuals:

Compete more for resources.

Are more easily located by predators and parasites.

Are more vulnerable to infection and disease.

Density dependent factors are biotic factors

such as food supply, disease, parasite

infestation, competition, and predation.

Parasites can spread rapidly

through dense populations

Competition increases

in crowded populations

Density Independent

FactorsThe effect of density independent factors

on a population’s growth is not dependent

on that population’s density:

•Physical (abiotic) factors

•Temperature

•Precipitation

•Humidity

•Acidity

•Salinity

•Catastrophic events

•Floods and tsunamis

•Fire

•Drought

•Earthquakes and Eruptions

When is a country overpopulated?

• The optimum pop. Is when pop. Produces

highest economic return per capita, using all

available resources.

• Some countries have higher optimum pop.

Densities than others

• Netherland has high pop. Densities but can

support this w/ high living standards

• Brazil in the north w/ 2 people for km2 is

overpopulated as resources are much scarcer.

When is a country overpopulated?

• richer countries import goods and services

from elsewhere.

Why do people have large families?

• High infant and childhood mortality rate

• According to UNICEF one child dies every 3

seconds (26,500 per day) due to malnutrition and

disease. It is an insurance to have more than you

may need so that some reach adulthood.

Why do people have large families?

• Security in old age

• The tradition in the family is that children will care

for their parents. The more children the more

secure the parents and less burden for each

child. If no social welfare network, children need

to take care of parents

Why do people have large families?

• Children are economic asset

• Agriculture society they work on the land asap.

More kids can help take care of younger ones.

• In MEDCs children depend on their parents and

take longer to contribute to society.

Why do people have large families?

• Status of women

• Traditional position of women they are

subordinate to men.

• In many countries deprived of many rights:

• Owning property

• Education

• Career

Why do people have large families?

• Status of women

• They do most agricultural work and are

considered worthy only for making children and

their social status depends on the number of

children they produce (especially boys)

Ways to reduce family size

• Provide education

• Basic literacy for children and adults

Ways to reduce family size

• Provide education

• Basic literacy for children and adults

Ways to reduce family size

• Improve health care

• By preventing the spread of diseases through

simple measures of hygiene (boiling water), by

improving nutrition, and providing medicine and

vaccines

Ways to reduce family size

• contraceptives

• Education on family planning and making

contraceptives available

Ways to reduce family size

• Enhance Income

• Small loans given to families to buy seeds or

equipment necessary to start a small family

business.

Ways to reduce family size

• Biggest factor in reducing population….

Improved status of women

Ways to reduce family size

• Improved status of women

• Fertility rates are high where women status is low

• Less than 20% world’s countries will account for

nearly all of the world population growth

• Those countries are least developed and girls are

most likely less to attend school

• Child marriage is common

• Women lack basic rights

Human Population growth and

resources

• More people require more resources

• More people produce more waste

• People usually want to improve their standard

of living

• So the more people there are, the greater the

impact they have

• If we can control pop. Increase and control

resource demand, levels of sustainability should

increase

Population growth and food

shortages

Use 2 pages of your notebooks one side for

Malthusian theory and the other for Boserup’s

theory.

• What are each?

• What are the limitations of each?

• What are the applications of each?

• Include graphs

• Pages 357-359

Carrying Capacity

• The largest number of individuals in a

population that the resources in the

environment can support for an

extended period of time

Farming 1800’s

Farming 2015

Solid Domestic Waste

What is SDW?

• Solid domestic waste

• It is only 5% of total waste, (Agriculture

and industry make up the other 95%)

however it is waste we can control.

• People in LEDCs tend to produce less

SDW than those in MEDCs

Types of solid waste

• Biodegradable: food

• Recyclable: Paper, glass, metals, some

plastic, clothes, batteries

• Electrical waste: TVs, computers,

phones

• Hazardous: paints, chemicals, light

bulbs

• Toxic: pesticides, herbicides

• Medical: needles

The linear Economy• Most goods are produced in a linear model

Dump: when done we

dump them

Take: find raw materials

or natural capital

Make: Use energy to

produce goods

Our global economy has been built on this

unsustainable premise

The Circular Economy

A model that is sustainable

• Restorative of environment

• Use of renewable energy

• Eliminate/reduce toxic waste

• Eradicate waste through careful design

To do this the model relies on manufacturers and

producers retaining ownership of their products and

being responsible for recycling when consumer is done.

They take back products when they are no longer

needed and disassembled or refurbished and then

returned back to the market.

Strategies to minimize waste• Reduce

• Have things last longer

• Items with less packaging

• Buy recycled made products

• Reuse

• Compost food waste

• Use old clothes for cleaning

• Rent DVD or buy downloadable copies

• Read E - books

• Recycle

• Collect and separate waste material

• The amount of domestic waste has

increased with population rise

• MEDC produce far more waste than

LEDC because of higher spending

power

• In India and China, very little food is

wasted, It is consumed entirely by

humans or animals

• In MEDCs up to 50% of waste is food

Strategies for waste disposal:

Landfills

• Critical issue in many parts of the world

• Landfills are good but space is running

out

• Strategies are dependent on the

composition of rubbish

Landfill

• A disposal site where solid waste is

buried between layers of dirt in such a

way to reduce contamination of

surrounding land.

• Lined with layers of absorbent material

and sheets of plastic to keep pollutants

from leaking into the soil and water

• When used it can be reused as a park

Advantages Disadvantages

• Relatively cheap

• Low technology that any country can

use

• Landfill occurs in specific locations that

can be carefully chosen and monitored

• Waste can be processed to remove

recyclable material

• Methane can be captured and used

• Limit to # of appropriate available sites

in many regions

• As sites become scarce the cost of

land increases

• Public opposition to opening new

landfill sites and expanding existing

ones because of environmental

concerns

• Poorly managed sites can pollute

water, soil and air

• Poorly managed sites attract animals

and insects that can spread disease

• Recognized as unsustainable way of

waste disposal

Incineration

• Burning waste material

• Require a limited land area reducing

volume of refuse greatly

• Incinerators are expensive to build and

operate

• Require a high input of energy

• Ash disposal needs a landfill

• Toxins are emitted (sulfur dioxide,

nitrogen dioxide, carbon dioxide)

Composting

• Organic material that has been

decomposed and recycled as fertilizer

because of its high nutrient value

• Many countries encourage households

to compost as much as possible in their

own gardens

Recycling

• Regarded as a key process in providing

a livable environment for the future

• Cost is significant

• Some waste can not be recycled and

the separation can be difficult

• LEDC have very few opportunities for

recycling

Anaerobic Digestion• Biodegradable material is broken by

microorganisms in the absence of O2

• The methane produced can be used as

fuel and the waste later used as fertilizer

or soil conditioner