1. Human Impacts on the Environment

2. People

3. Population All the members of a species living in a given area
Human population has exploded over the last couple centuries
due to improved health care, clean water, etc

4. Carrying Capacity
The largest number of individuals of a given species that Earth’s resources can support and maintain for a long period of time
populations that exceed carrying capacity will begin to die off due to lack of resources (food, water, space)

5. Impacts on Land

6. Humans Using Land - Forest Resources
Trees are cut down to make wood and paper products, and to clear land for development
Deforestation
removal of large area of forests for human purposes

7. Effects of Deforestation
Habitat destruction
Soil erosion
plant roots hold soil in place; without plants the soil erodes away
Air quality
less oxygen and more carbon dioxide in the air

8. Humans Using Land - Agriculture
Large areas of land cleared for farming and cattle grazing
Effects of Agriculture
Fertilizers
add excess nitrogen to the soil
pollute groundwater
Desertification
the development of desert-like conditions due to human activities
can occur due to soil erosion and/or over farming

9. Humans Using Land - Mining
Removal of rocks and minerals from the ground
Effects of Mining
disturbing habitats
changes the landscape
water pollution from runoff

10. Construction and Development
Urbanization
the movement of human populations into cities
Urban Sprawl
the development of land for houses and other buildings near a city
Effects of Urbanization
habitat destruction
reduced water quality due to increased runoff

11. Positive actions Preservation
Governments can protect land by setting aside wild areas
There are laws about how the resources there can be removed
Forests are complex but they can be managed to preserve the ecosystem
Select-cutting- only certain trees in one area are cut down rather than lots of trees or all the trees
Reforestation- replanting trees that have been cut or burned down
Reclamation- restoring land that has been disturbed by mining

12. Positive actions Green Spaces
Cities use green spaces to create natural environments in urban settings
They provide places for recreation for people and habitat for wildlife
They reduce runoff and improve air quality as plants take up extra carbon dioxide

13. Positive actions Reusing, Reducing, & Recycling Composting
Reduces the amount of trash that ends up in landfills.
It involves mixing food scraps, leaves, and grass clippings and adding the decayed product to soil.

14. Impacts on Water

15. Water as a Resource
most water is used in power plants to generate electricity

16. Sources of Water Pollution
Point-Source Pollution
Nonpoint-Source Pollution
pollution from a single source that can be identified
ex. oil spills, mining runoff
pollution from several widespread sources that cannot be traced to a single location
ex. agricultural and urban runoff
Most of the United States’ water pollution is nonpoint-source

17. Positive Actions National Initiatives: How You Can Help:
Clean Water Act
regulates sources of water pollution
Safe Drinking Water Act
protects supplies of drinking throughout the country
How You Can Help:
Reduce use of harmful chemicals
Dispose of waste safely
Conserve water

18. Impacts on the Atmosphere

19. Types of Air Pollution - Smog
nitrogen and carbon compounds are released from burning fossil fuels
these compounds react with sunlight to make ozone and other chemicals

20. Types of Air Pollution – Acid Rain
rain or snow that has a lower pH than that of normal rainwater
makes soil more acidic, making it difficult for plants to survive

21. Other Types of Air Pollution
Particulate Matter
mix of both solid and liquid particles in the air
ex. smoke, dust
CFCs
destroy ozone molecules
Carbon Monoxide
released from cars and forest fires

22. Global Warming
burning fossil fuels releases excess amounts of carbon dioxide into the air
this can lead to an increase in Earth’s average surface temperature

23. Effects of Global Warming
Melting of ice caps and a rise in sea level
More storms due to higher ocean temperatures
Extinction of cold-weather species

24. The Greenhouse Effect
The natural process that occurs when gases in the atmosphere absorb and reradiate thermal energy from the Sun
Increased carbon dioxide traps more heat in the atmosphere

25. Health Disorders
Air pollution can cause respiratory problems, including asthma attacks, in which the passageways in the lungs become narrower and breathing becomes difficult.
The government measures and reports air quality using the Air Quality Index, which is a scale that ranks the level of ozone and other pollutants.

26. Positive actions Montreal Protocol Clean Air Act
Countries around the world have agreed to phase out CFC’s and to lower emissions of green house gases to help reduce problems due to Air pollution
Clean Air Act
Since it was passed in 1970, we have seen a 50% reduction in pollutants that cause acid rain and a 90% reduction in air pollution from factories.

27. Positive actions Using Renewable Energy Using Less Energy
Renewable resources such as solar power, wind power, and geothermal energy helps reduce air pollution
Using Less Energy
Helps reduce pollution and improve the quality of all our important resources: water, air, soil