Lecture 31: Human Impacts Flashcards
-Ecological Footprint and Carrying Capacity -Humanity's Impact by Population Pressure and Resource Needs -Humanity's Impact on the Atmosphere
What is the global population?
7.77 billion
What is the annual growth rate of the global population?
- 2%
- Addition of more than 80 million people every year
Give an example as to why the impacts of population are related to standards of living and resource utilization.
- 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
What is an ecological footprint?
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)
What are the ecological footprints of Canada and the USA, in terms of total per person?
Canada: 7.7 ha/person
USA: 8.1 ha/person
-among the highest in the world
What two countries have the greatest ecological footprint, in terms of total per country?
China and the USA
What is the definition of the carrying capacity (biocapacity) of Earth?
The maximum population of people that the planet can sustain.
What is exponential population growth?
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.
What is logistic population growth?
Population expansion decreases as resources become scarce, leveling off when the carrying capacity of the environment is reached.
How many Earths does it take to support humanity today?
- 75 Earths
- If everyone used the same resources as an average Canadian, that number would exceed 3 Earths
What is the general culprit of climate change?
Resource extraction
How much of food is wasted in the US?
30-40%
-20 pounds of food per person per month
What is desertification?
The expansion of desert into previously productive lands.
What can cause desertification?
Land degradation due to overgrazing or over-irrigation.
-Can result in soil salinization
Why is soil considered a non-renewable resource?
Because soils form on timescales that are thousands of years, while global soil loss is occuring at ~7% per decade.
What is an issue with landfills?
Widespread soil and water contamination by inorganic and organic substances that are toxic to ecosystems and human health.
How many people have access to clean drinking water in the world?
91%
What are ‘commons’?
Something shared by everyone.
-The atmosphere
What is the main mechanism by which contaminants touch all parts of the world?
Atmosphere transportation
What is biomagnification?
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.
Where does a lot of the long-range transportation of pollution acccumulate?
The Artic
What are the effects of acid rain?
- 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
Where is there a hole in the ozone layer?
Over Antarctica
What is causing the breakdown of the ozone layer?
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
How is climate change affecting the “point of crisis”?
It affects recovering fish stocks, is crippling agriculture and water supplies through drought.
-Our technology may not be able to overcome it.
What is the precautionary principle?
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.
