1. Ozone Layer Depletion

2. Think Pair Share
Alone, then in groups, I want you to come up with your own definition for what greenhouse gases are
After you have written down your definition, share it with your desk partner and compare answers
We will write down several answers

3. Videos!
During each video I want you to pay careful attention to the causes, effects, and solutions that are presented
Discussion to follow to see what you saw

6. The Ozone Layer
Belt of naturally occurring ozone gas that sits about 30 kilometers above surface of the earth
Meant to shield the surface from the harmful ultraviolet B radiation emanated from the sun
Constantly being formed and broken down in our atmosphere, the molecule itself is three oxygen atoms

7. Chlorofluorocarbons (CFCs)
Chemicals found in aerosol products heavily used by industrialized nations over the last 50 years are the main culprit
When these reach atmosphere they are broken down by sunlight and heat, releasing chlorine with reacts with the oxygen (ozone), ripping apart the molecule

8. What do they cause?
Breaking down of the ozone layer puts holes into our shield
More ultraviolet radiation gets in, increasing skin cancer and cataracts in humans as well as other animals
Also affects phytoplankton in the water, essential for survival of aquatics
Also seen to inhibit reproduction abilities of marine animals and fish

9. The Arctic Layers
Ozone layer above the Antarctic has been particularly impacted by this problem
Low temperatures speed up the conversion of CFCs into chlorine and others
Close to 65% of the ozone layer has been depleted

10. Who’s at fault?
We are
90% of CFCs come from Northern Hemisphere industrialized nations
One solution was to ban CFCs, which has caused the amount of Chlorine in the atmosphere to dwindle, however it’ll take another 50 odd years for levels to go back to more manageable numbers

11. Activity
Go to the United States Environmental Protection Agency (EPA) website
Research greenhouse gases
Take notes on what you find, as you will need them for the later discussion

12. Predicting Events
In your table groups, come up with a list of ways you believe climate change might effect humans in the next 100 years.
You can get creative if you’d like, but you’ll need to back up claims with some viable evidence
You will be presenting your findings to the class