1. POPULATION GROWTH PLACES A STRAIN ON A COUNTRY’S RESOURCE BASE (food, water, energy) IMPORTANT CONNECTION BETWEEN POPULATION AND RESOURCES

2. ? What accounts for the change around 1800?

3. DEMOGRAPHY Part 1.

4. 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 DEATHSWEALTH MIGRATIONDENSITY

5. Demographers use rates… (*stats from 2003) Births per day in Canada: 906 Births 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 1000 Total Population Canada: 330 690 x 1000Russia: 1 400 140 x 1000 32 000 000 143 000 000 = 10 births/ 1000 people= 10 births / 1000 people

6. How do Populations Change? 4 ways… Naturally: 1) Births and 2)Deaths Migration: 3) Immigration and 4)Emigration

7. How do populations change? Natural Change (Births and Deaths) Birth Rate (# of births per year / population) x 1000 Death 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 1000 Emigration Rate (# of emigrants per year/population) x 1000 Balance between Immigration and Emigration is “Migration Rate” Migration Rate = Immigration Rate – Emigration Rate

8. Population Growth Rate The overall growth of a population can be determined by adding the natural increase rate and the net migration rate. e.g. Canadian Example 3/1000 + 5/1000 = 8/1000 (0.8%)

9. Densitopia Densitopia is a small country with an area of 56 000 km 2. 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?

10. Population Density Population Density is a measure of the number of members of a population in a given area. It is usually measured in km 2. PD = # of people/area e.g. Country/LandmassDensity (people/km 2 ) World41 Singapore7 148 Canada3.4 Toronto3 972

11. DEMOGRAPHY Part 2.

12. 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 1OPTION 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 192DAY 13: $13 000 DAY 20: $524 288 DAY 20: $20 000 HOW DOES THIS SCENARIO RELATE TO HUMAN POPULATION GROWTH?

13. Population Growth Human 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% YEARPopulation% increaseAmount Added to Population 110020 21202024 31442029 41732035 52072042 62492050 72992060 Population has doubled in less than 5 years.

14. Doubling Time Doubling 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

15. Population Pyramids A 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 Adults 3)Children ( <15) The 65+ and under 15 segments of the population are part of what is called the Dependency Load.

16. 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?

17. 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/resources 3) Using demographic equations, we can track the changes in a given population, and make predictions about future population characteristics.