POPULATION GROWTH PLACES A STRAIN ON A COUNTRY’S RESOURCE BASE (food, water, energy)

IMPORTANT CONNECTION BETWEEN POPULATION AND RESOURCES

?

What accounts for the change around 1800?

DEMOGRAPHY Part 1.DEMOGRAPHY Part 1.

Demography: The study of population and population statistics. Greek: “demos” –”common people”

Demographers examine issues relating to the structure, size, and distribution of human populations.

E.G.

GROWTH RATE (speed of growth) HEALTH

BIRTHS AND DEATHS WEALTH

MIGRATION DENSITY

Demographers use rates…(*stats from 2003)

Births per day in Canada: 906Births per day in Russia: 3 836

Which country is growing fastest due to births?

Population: 32 million

Population: 143 million

In order to compare the births in each country, we use the Birth Rate:

Birth Rate = # of births per year x 1000Total Population

Canada: 330 690 x 1000 Russia: 1 400 140 x 100032 000 000 143 000 000

= 10 births/ 1000 people = 10 births / 1000 people

How do Populations Change?4 ways…Naturally: 1) Births and 2)Deaths

Migration: 3) Immigration and 4)Emigration

How do populations change?Natural Change (Births and Deaths)Birth Rate (# of births per year / population) x 1000Death Rate (# of deaths per year / population) x 1000

Balance between Births and Deaths is “Natural Increase Rate”

Natural Increase Rate = Birth Rate – Death Rate

MIGRATION (Immigration and Emigration)Immigration Rate (# of immigrants per year/population) x 1000Emigration Rate (# of emigrants per year/population) x 1000

Balance between Immigration and Emigration is “Migration Rate”

Migration Rate = Immigration Rate – Emigration Rate

Population Growth RateThe overall growth of a population can be determined by

adding the natural increase rate and the net migration rate.

e.g. Canadian Example3/1000 + 5/1000 = 8/1000

(0.8%)

DensitopiaDensitopia is a small country with an area of

56 000 km2. It has a total population of 8,460,000 people. Each year, 14 268 babies are born and 12 426 people die. A recent economic boom has attracted 16 924 immigrants, while 9 445 people emigrated, mainly to work in the mining industry in neighboring Sparsitania.

What is the population growth rate of Densitopia?

Population DensityPopulation Density is a measure of the number of members of a population in a given area. It is usually measured in km2.

PD = # of people/areae.g.

Country/Landmass Density (people/km2)

World 41

Singapore 7 148

Canada 3.4

Toronto 3 972

DEMOGRAPHY Part 2.

How do populations grow?The Money Example:You receive money each day for a 20-day period. You can either receive a doubling amount of money each day, starting at $1, or $1000 each day.WHICH OPTION WOULD YOU CHOOSE?

OPTION 1 OPTION 2

$1 on day 1,$2 on day 2,$4 on day 3,$8 on day 4……for 20 days.

$1000 a day for 20 days

DAY 13: $8 192 DAY 13: $13 000

DAY 20: $524 288 DAY 20: $20 000

HOW DOES THIS

HOW DOES THIS

SCENARIO RELATE

SCENARIO RELATE

TO HUMAN TO HUMAN

POPULATION POPULATION

GROWTH?GROWTH?

Population GrowthHuman populations do not double each year, but they do double over time. Generally, countries have rates of growth between -2% and 4%. Canada’s PGR is 0.9% (or 9/1000).

COMPOUNDING: The ability of a population to build upon itself over time due to its growth rate adding to its base.

e.g. population of 100 people. Growth Rate of 20% YEAR Population % increase Amount Added to Population

1 100 20 20

2 120 20 24

3 144 20 29

4 173 20 35

5 207 20 42

6 249 20 50

7 299 20 60

Population has doubled in less than 5 years.

Doubling TimeDoubling Time is the amount of time it takes for a population to double in size. It can be calculated using the Rule of 70.

Rule of 70: Doubling Time = 70 / PGR (as a percent)

e.g. In Togo, the PGR is 24/1000 or 2.4%. In order to estimate the doubling time of Togo we divide 70 by 2.4.

DT of Togo = 70/2.4 = 29 years

Population PyramidsA population pyramid is a type of double bar graph that represents the size of a population according to 5 year age segments and is divided by sex.

The base of the pyramid can be a population value or a percentage.

Populations are divided into three major categories based on age:1)Older Adults (65+)2)Working Adults3)Children ( <15)

The 65+ and under 15 segments of the population are part of what is called the Dependency Load.

Canada’s Demographic Future

How will Canada’s population change over the next 40 years?

How will the three main age categories be affected, and how will the dependency load of the population change?

In 2050…What will be the approximate population of Older Adults? Of Children? Of Working Adults?

What percentage of the overall population will be part of the dependency load?

Take Home Message(s)…

1) The global population is rising at a dramatic rate

2) Population growth puts stress on the landscape (pollution, waste, resource extraction), and creates challenges for humans.

e.g. distribution of food/resources3) Using demographic equations, we can track

the changes in a given population, and make predictions about future population characteristics.