1. Environmental Science 20
HUMAN POPULATIONS
Environmental Science 20

2. Human Populations
Human population trends are centrally important to environmental science because they help to determine the environmental impact of human activities.
Rising populations put increasing demands on natural resources such as land, water, and energy supplies.
As human communities use more resources, they generate contaminants, such as air and water pollution and greenhouse gas emissions, along with increasing quantities of waste.

3. Population demographics
Definitions:
Population – The number of people living in a region
Birth Rate – The number of births per 1000 people per year
Death Rate – The number of deaths per 1000 people per year
Rate of Natural Increase – Growth caused by having more births than deaths in a year (does not include immigration and emigration)
Doubling Time – The number of years it will take for the population to double in size if it maintains its current growth rate

4. Population Demographics
World Population Demographics
The 2015 world population is 7.2 billion
The birth rate is 21 per 1000
The death rate is 9 per 1000
The world’s annual growth rate is 1.2%
At this rate the world’s population will double to 14 billion in 58 years

5. Population demographics
Extra Information:
A population grows whenever the birth rate is higher than its death rate
The growth rate is determined by the size of the difference between the birth and death rates. The closer these rates are, the lower the growth rate
Where birth and death rates are equal, the population’s growth rate is zero
The world’s current birth rate is almost two and a half times its death rate

7. Life Expectancy

8. Population demographics
Discussion Questions:
What will it mean to have our population double? What else will we need to have twice as much of to provide for all of these people?
Food
Land
Water
Shelter
Schools/hospitals
Energy
2. Asia’s doubling time is 58 years. If we returned in years and did this activity again, would we be able to fit twice as many people into Asia’s space?

9. Arable Land – Farmland; land capable of growing crops
Land Use Patterns
Definitions:
Urban Population – Percentage of the total population living in areas termed urban by that country (typically towns with 2000 or more)
Arable Land – Farmland; land capable of growing crops

10. Land Use Patterns World wide Land Use Patterns:
48% of the world’s population now live in urban areas
There are 0.5 acres of arable land per person on Earth.

11. Land Use Patterns Extra Information:
The rate of urbanization is changing rapidly as more people are moving into cities
As a population grows, the economic, social, and environmental problems grow as well
Regarding Arable Land
The lowest estimate of the minimum amount of arable land required to feed one person – without intensive use of synthetic fertilizers – is 0.17 acres. (not including crops for textiles)

12. Land Use patterns
Discussion Questions:
How will population growth affect the amount of arable land available per person?
When people share a limited resource such as arable land, each person’s share become smaller as additional people are using the resource
What would it mean for a country to have its amount of arable land per capita fall below the minimum required to grow enough food to sustain its population?
Such a country would become dependent of imported foods, making it vulnerable to price hikes and shortages
What do you think usually causes people to move to cities?
The shift of jobs from agriculture to industry and services – leading to concentration of economic opportunities in urban areas
What are some possible positive and negative effects of having such large proportions of countries’ population shifting to urban areas?

13. Positive Effects Negative Effects
More green space is left open for:
Species to inhabit
Trees and plants to produce oxygen
Potential farmland
Higher rates of unemployment and poverty
More people need jobs than are available
Can happen in spite of economic growth
Well planned cities can offer people:
More job opportunities
Better public services and living conditions
Greater Environmental problems
Streets congested
More pollution
Heavy use of sanitation
Quality of life decline

14. Energy consumption and wealth
Definitions:
Energy Consumption – The total amount of energy used by each region per year divided by the number of people living in that region – includes industrial use
Gross Domestic Product (GDP) – A commonly used measure of a nation’s wealth, determined from the annual profits generated within a region by all goods and services exchanged that year

15. Population Simulation Activity
Fill in your predictions for the Human Population Demographics Handout.
Get into groups representing the approximate populations of the following 5 regions:
North America
Latin America
Europe
Africa
Asia
Elect one person be the Ambassador for the region.
The Ambassador will now read the Ambassador card. Fill in the information on the Results side of the Human Population Demographic Handout. Compare the results with your predictions.
Gather the Results for each of the other 4 regions.
Send the Ambassador to collect your region’s resources. Count what you have.
Answer the last set of questions on the Handout.

16. Energy consumption and wealth
Symbolism of Props
Matches:
While energy can be generated in many ways, all sources are being expressed in barrels of oil
The matches represent the average energy consumed by each citizen per year
Each match – the amount of energy generated from burning 1 barrel of oil
Candies:
The candies represent the amount each person would get per year if the region’s annual GDP were divided equally among all citizens
1 candy - $500.00

17. Energy Consumption and wealth
Discussion Questions:
What would it be like if we lit all the matches? Who would have to breath in all that smoke?
What do the people in Asia and Africa think about the fact that North Americans have so much and they have so little?
How could people from regions with less wealth get access to those things?
In the process of eating the candies, which region generated the most empty wrappers? Do you think this is an accurate representation of how much garbage each country creates as a function of its wealth and consumption?
What do you think should be done about inequitable distribution of wealth and consumption of resources? Do some nations have the right or obligation to help other countries become more self-sufficient in the future? Should rich countries be required to reduce their consumption levels? How could this be encouraged or enforced? What should be done about environmental issues caused by one region, but affecting others?