1. Impact of Human Population on the Environment
Objective 5.03: Assess human population and its impact on local ecosystems and global environments

2. Hole in the Ozone Layer
Ozone, O3, is a naturally occurring gas that collects in the stratosphere and shields the Earth from harmful ultraviolet radiation released from the Sun.

3. One CFC can destroy 100,000 ozone molecules
Hole in the Ozone Layer
Certain synthetic chemicals, especially chlorofluorocarbons, CFCs, rise into the stratosphere and act as catalysts that break down ozone faster than its formed.
One CFC can destroy 100,000 ozone molecules

4. Hole in the Ozone Layer
CFCs are commonly used as coolants in air conditioners, cars, and refrigerators. CFCs are also used in aerosol spray cans and to make Styrofoam products.

5. Hole in the Ozone Layer
Since the 1980’s, atmospheric measurements have shown a periodic hole in the ozone layer over Antarctica. As a result, the amount of skin cancer and cataracts have increased worldwide.

6. Hole in the Ozone Layer
International effort began to reduce the use of CFCs by using substitutes and to only allow licensed mechanics to change Freon in car air conditioners.
The ozone hole is decreasing yearly and can be expected to be fully repaired by 2050

7. Increased CO2 Levels
Since the industrial revolution that began in the 1850’s, the levels of carbon dioxide in the atmosphere has increased by over 30%

8. Increased CO2 Levels
Reasons for the increase in CO2 levels are mainly due to increase in burning of fossil fuels for energy or combustion

9. Increased CO2 Levels
CO2 is released from coal power plants; combustion engines; and from burning wood especially forests.
Slash and burn practice of clearing tropical rainforests to make room for more farmland

10. Increased CO2 Levels

11. Increased CO2 Levels
Not only does the burning of a forest release CO2 into the atmosphere, it also reduces trees that are able to remove and store a lot of CO2 from the atmosphere during photosynthesis

12. Increased CO2 Levels
Carbon dioxide is one of the greenhouse gases. Other greenhouse gases include: water vapor, methane, CFCs, Ozone, and nitrous oxide.
Methane is the second largest contributor to increase in greenhouse gases

13. Greenhouse Effect
Methane is released by cows, every time they breathe. However, methane is also released from mining practices, landfills, and during the production of gas products.

14. Greenhouse Effect
A Greenhouse, made of glass, allows light radiation in that heats the ground. Heated objects emit infrared radiation, heat, that cannot pass through glass and becomes trapped.

15. Greenhouse Effect
In the atmosphere, greenhouse gasses allow light radiation to pass through but trap infrared radiation, thus keeping the Earth warm.
95% of the atmosphere on Venus is 95% CO2 – Temperatures on Venus reach 900F

16. Global Climate Change
Measurements from ice cores in Antarctica, the temperature has varied periodically through time. Changes in CO2 levels coincide with the changes in temperature.

17. Global Climate Change Cooling
Decrease in atmospheric CO2  Decrease in Temperature
Decrease in Temperature  Glacial Formation
Glacial Formation  Higher reflection of sunlight
Higher reflection of sunlight  Lower light intensity
Lower light intensity Shorter Growing Seasons
Shorter growing season  Less photosynthesis
Less photosynthesis Increase in atmospheric CO2

18. Global Climate Change Warming
Increase in atmospheric CO2 Increase in temperature
Increase in temperature  Melting of glaciers
Melting of glaciers  Decrease of light reflection
Decrease of light reflection  Increase in light intensity
Increase in light intensity  Increase in Photosynthesis
Increase in photosynthesis Decrease in atmospheric CO2
Decrease in atmospheric CO2  Decrease in Temperature

19. Global Climate Change
Since the 1900’s, global levels of atmospheric CO2 have increased dramatically.
The increase with CO2 levels do coincide with the advent of the industrial revolution.

20. Global Climate Change
Since the 1900’s, there has also been an increase in global temperature.
Although there has been periodically cooler years, the overall trend is still increasing.

21. Global Climate Change
Scientists use carbon isotopes to determine if atmospheric CO2 was derived from the burning of fossil fuels or natural earth’s processes
Climate Model – Both natural CO2 and that from the burning of fossil fuels

22. Climate Model – Just atmospheric CO2 from natural earth’s processes
Global Climate Change
Evidence shows that atmospheric levels CO2 from natural Earth’s processes has not increased over the past 100 years.
Climate Model – Just atmospheric CO2 from natural earth’s processes

23. Global Climate Change
If the warming trend continues, it could lead to a change in our global climate where there is a significant change in the “average” temperature

24. Global Climate Change
Possible changes if the global climate changes could include:
Melting of Polar Ice Caps
Rise in Sea Level
Disappearance of Many Islands
Flooding of Major Coastal Cities

25. Global Climate Change
Possible changes if the global climate changes could include:
More Extreme Weather Patterns(Hot and Cold)
Change in Agricultural regions
Destruction of Coral Reefs

26. Acid Rain
Acid rain is created when sulfur oxides and nitrogen oxides from the burning of fossil fuels combine with rain to make it more acidic

27. Acid Rain
Acid rain washes minerals such as calcium and magnesium from the soil that plants need to grow

28. Smog
Smog refers to a mixture of smoke and fog in the air. Smog traditionally arose from smoke released from coal burning plants. However, since the 1950’s, the largest contribution to smog has been from automobile exhaust.

29. Smog
Smog is created when nitrogen oxides (NOx) and volatile organic compounds (VOC’s) react under sunlight to form ozone.
While ozone in the upper stratosphere blocks harmful ultraviolet radiation, it is harmful upon exposure, in the lower troposphere

30. Smog
Smog or ozone is particularly harmful to older and very young people, as well as people with existing respiratory issues.

31. Smog
The EPA now monitors ozone levels on a daily basis and issues ozone warning when levels reach dangerous levels, especially in the summer time.

32. The End