Lecture 31: Human Impacts

Question 1

What is the global population?

Answer 1

7.77 billion

Question 2

What is the annual growth rate of the global population?

Answer 2

1. 2%

- Addition of more than 80 million people every year

Question 3

Give an example as to why the impacts of population are related to standards of living and resource utilization.

Answer 3

• Poorest countries have the highest birth rates but live in poverty.
• A large family in Somali wouldn’t use as many resources as a smaller North American family
• More resources are used in developed countries that what is available

Question 4

What is an ecological footprint?

Answer 4

The measure or resources needed to support a person or community, in terms of land area.

• Measured in hectares/person
• Can also be measured per country (multiply the average footprint of a person in a country by its total population)

Question 5

What are the ecological footprints of Canada and the USA, in terms of total per person?

Answer 5

Canada: 7.7 ha/person
USA: 8.1 ha/person
-among the highest in the world

Question 6

What two countries have the greatest ecological footprint, in terms of total per country?

Answer 6

China and the USA

Question 7

What is the definition of the carrying capacity (biocapacity) of Earth?

Answer 7

The maximum population of people that the planet can sustain.

Question 8

What is exponential population growth?

Answer 8

When a population’s per capita growth rate stays the same, regardless of population size, making the population grow faster and faster as it gets larger.

Question 9

What is logistic population growth?

Answer 9

Population expansion decreases as resources become scarce, leveling off when the carrying capacity of the environment is reached.

Question 10

How many Earths does it take to support humanity today?

Answer 10

1. 75 Earths

- If everyone used the same resources as an average Canadian, that number would exceed 3 Earths

Question 11

What is the general culprit of climate change?

Answer 11

Resource extraction

Question 12

How much of food is wasted in the US?

Answer 12

30-40%

-20 pounds of food per person per month

Question 13

What is desertification?

Answer 13

The expansion of desert into previously productive lands.

Question 14

What can cause desertification?

Answer 14

Land degradation due to overgrazing or over-irrigation.

-Can result in soil salinization

Question 15

Why is soil considered a non-renewable resource?

Answer 15

Because soils form on timescales that are thousands of years, while global soil loss is occuring at ~7% per decade.

Question 16

What is an issue with landfills?

Answer 16

Widespread soil and water contamination by inorganic and organic substances that are toxic to ecosystems and human health.

Question 17

How many people have access to clean drinking water in the world?

Answer 17

91%

Question 18

What are ‘commons’?

Answer 18

Something shared by everyone.

-The atmosphere

Question 19

What is the main mechanism by which contaminants touch all parts of the world?

Answer 19

Atmosphere transportation

Question 20

What is biomagnification?

Answer 20

The concentration of toxins in an organism as a result of its ingesting other plants or animals in which the toxins are more widely disbursed.

Question 21

Where does a lot of the long-range transportation of pollution acccumulate?

Answer 21

The Artic

Question 22

What are the effects of acid rain?

Answer 22

• It can degrade materials like concrete, stone, rubber, and plastics
• Can cause trees to be more susceptible to disease and death
• Acidify lakes and wet lands, causing the death of aquatic organisms
• Acidify soils, reducing agricultural productivity

Question 23

Where is there a hole in the ozone layer?

Answer 23

Over Antarctica

Question 24

What is causing the breakdown of the ozone layer?

Answer 24

Compounds called chlorofluorocarbons (CFCs)
-uv rays causes a chlorine to break free of the CFC molecule which reacts with ozone to make O2 and then the chlorine is free again to cause more reactions

Question 25

How is climate change affecting the “point of crisis”?

Answer 25

It affects recovering fish stocks, is crippling agriculture and water supplies through drought.
-Our technology may not be able to overcome it.

Question 26

What is the precautionary principle?

Answer 26

If the potential consequence of an anticipated event are unacceptably severe, those in authority have a responsibility to take action to avoid or mitigate those consequences.