HUMAN POPULATION GROWTH

WHY STUDY HUMAN POPULATION

GROWTH

• Human population growth is a crucial topic as it affects resources,

ecosystems, and global sustainability.

• Understanding its trends helps address environmental, economic,

and social challenges.

HUMAN POPULATION

• Human population refers to the number of people living in a

particular area, from a village to the world as a whole.

• The number of people living in the Philippines as of July 18,

2023 is 119,106,224 If we compare this data from the one in

1950, there were only about 18,580,480 people living in the

Philippines.

FACTORS THAT AFFECT HUMAN

POPULATION GROWTH

• Fertility rates

• Increase in longevity

• The initial age profile of the population

• International migration

FERTILITY RATES

Population growth is highly

dependent on trends in fertility

rates. The global fertility level is

expected to decline from 2.5

children per woman in 2019 to 2.2

in 2050, according to the World

Populations Prospects study from

the UN.

INCREASE IN LONGEVITY

• an estimate of the expected life span of an average

newborn child – has been rising around the world.

According to the United Nations, global life expectancy at

birth increased from 48 years in the 1950 to 1955 period to 69

years in 2010-2015, and it is expected to continue to rise

over the next four decades.

THE INITIAL AGE PROFILE OF THE

POPULATION

The world’s population will increase as people live longer. From 1950 until

about 1980, the median age of the world’s population remained in the low

20s. By 2010, however, the median age of the population was 28 years. And

by 2050, the global median age is expected to be 37,

MIGRATION

When people move into a country (immigrate), it directly increases the

population. Immigrants contribute to both the current population and future

growth.

EFFECTS OF HUMAN POPULATION

GROWTH ON EARTH’S RESOURCES:

RESOURCE EXTRACTION

As the global population grows, so does the demand for

resources. We extract fossil fuels (like oil, gas, and coal),

minerals, trees, water, and wildlife from the environment.

Unfortunately, this extraction often releases pollutants and

waste, harming air and water quality and affecting human

and ecosystem health.

BURNING OF FOSSIL FUELS

The need for energy drives increased burning of fossil fuels.

Whether for electricity generation, transportation (cars,

planes), or industrial processes, this contributes to air pollution,

climate change, and resource depletion.

FRESHWATER USE

Growing populations require more freshwater for drinking,

agriculture, recreation, and industry. Lakes, rivers,

groundwater, and man-made reservoirs are tapped,

impacting local ecosystems and water availability

ECOLOGICAL IMPACTS

Urbanization and agricultural

expansion lead to habitat

destruction. Forests are cleared

for homes, businesses, and

roads. This disrupts ecosystems,

decreases species populations,

alters biodiversity, and affects

interactions among organisms.

FISHING AND HUNTING

As populations increase, so does the demand for food.

Overfishing and excessive hunting reduce species

populations. Interestingly, this can indirectly benefit nontarget

species if more resources become available in the

ecosystem

DISEASE TRANSMISSION

Densely populated areas facilitate rapid disease spread.

Improved transportation also means diseases can leap across

regions more swiftly.

ACTIVITY

Propose measures to lessen

population growth and its effect

to the Earth’s resources

POPULATION DYNAMICS

DEMOGRAPHY

refers to the statistical study of human

populations, particularly focusing on

various aspects related to population size,

density, distribution, and vital statistics

(such as births, marriages, and deaths)

DEMOGRAPHIC MEASURES

These are the statistical tools demographers use to describe populations. Let’s

explore a few key ones:

• Birth Rate (Crude Birth Rate): The number of live births per 1,000 people in a

given year.

• Death Rate (Crude Death Rate): The number of deaths per 1,000 people in a

given year.

• Life Expectancy: The average number of years a person can expect to live,

based on current mortality rates.

• Population Density: The number of individuals per unit area (e.g., people per

square kilometer).

DEMOGRAPHIC MEASURES

• Age Structure: The distribution of population by age groups (e.g., children,

working-age adults, elderly).

• Total Fertility Rate (TFR): The average number of children a woman is

expected to have during her lifetime.

• Net Migration Rate: The difference between immigration and emigration

rates.

POPULATION GROWTH RATE

POPULATION PYRAMIDS

AGE-SEX STRUCTURE

refers to the number of individuals of sex and age group in the population. The

numbers of males and females in young, middle, and older age groups

determine how fast a population grows or declines. It is represented by a

special type of graph called population pyramid.

TYPES OF POPULATION PYRAMIDS

EXPANSIVE

Expansive population pyramid is used to describe populations

that are young and growing. They are often characterized by

their typical ‘pyramid’ shape, which has a broad base and

narrow top.

These types of populations are typically representative of

developing nations, whose populations often have high

fertility rates and lower than average life expectancies.

CONSTRICTIVE

• Constrictive population pyramid is used to describe populations

that are elderly and shrinking.

• It can often be seen like beehives and typically have an inverted

shape with the graph tapering in at the bottom.

• It represents a smaller percentages of people in the younger

age cohorts and are typically characteristic of countries with

higher levels of social and economic development, where

access to quality education and health care is available to a

large portion of the population.

STATIONARY

• Stationary or near stationary population pyramid is used to describe a

population that is not growing

• They are characterized by their rectangular shape, displaying somewhat

equal percentages across age cohorts that taper off toward the top.

• These pyramids are often characteristic of developed nations, where birth

rates are low and overall quality of life is high.

INTERPRETATION OF POPULATION

PYRAMIDS OF

SOME COUNTRIES

• The population pyramid of

Nigeria (2015) has a broad

base of young children and

tapered sides showing

rapidly decreasing

numbers of people at older

ages. This represents an

expansive population.

This next graph is

owned by France

(2015), showing a

narrow base of

children and

young adults,

reflects relatively

low birth rate over

the past several

decades.

The last example that

will be presented here

is the population

pyramid of Egypt

(2010). The 2010

population pyramid of

Egypt has a youth

bulge in the young

adult age groups.