Lesson 4 "Ozone Depletion: The future?"

1. Lesson 4 "Ozone Depletion:  The future?" Ozone module prepared by Eugene C. Cordero

2. Outline • What are current levels of ozone depletion? • Is the ozone hole getting worse? • What has been done about ozone depletion? • What is going to happen in the future? Ozone module prepared by Eugene C. Cordero

3. Global Ozone Trends Most of Australia does not have large negative ozone trends Ozone module prepared by Eugene C. Cordero

4. Globally, ozone has been decreasing over the last 15 years. Largest ozone change over Antarctica ~ -8% per decade or more No ozone change over Tropics Over Australia Melbourne: decreasing at 2-3%/decade Darwin: No significant change How has ozone changed over other parts of the Earth? Ozone module prepared by Eugene C. Cordero

5. Is the ozone hole getting worse? Ozone module prepared by Eugene C. Cordero

6. What is being done about ozone depletion? • Montreal Protocol (1988): international agreement to phase out ozone depleting chemicals • Further amendments accelerated the phase out. • Developed countries have switched to HCFC’s (more ozone friendly) instead of CFC’s. • Developing countries has until 2010 to phase out CFC’s. Ozone module prepared by Eugene C. Cordero

7. Observations indicate that chlorine is beginning to decline in the atmosphere. (Good news!) Still large uncertainties about illegal trade/use of CFC’s (??’s) Future Atmospheric models suggest that: atmospheric chlorine will return to pre-80’s in next 50 to 100 years. a slow ozone recovery will follow decreasing chlorine concentrations Is the Montreal Protocol working? Ozone module prepared by Eugene C. Cordero

8. Model simulations suggest: atmospheric chlorine will return to pre-80’s in next 50 or more years. a slow ozone recovery will follow decreasing chlorine concentrations Still many questions!!! Phase out and use of CFC’s Contribution from global warming What is going to happen in the future? Ozone module prepared by Eugene C. Cordero

9. Graph of CFC’s levels starting to fall off Ozone module prepared by Eugene C. Cordero

10. Chlorine in the future? Ozone module prepared by Eugene C. Cordero

11. Potential Chlorine growth Ozone module prepared by Eugene C. Cordero

12. No direct connection between these environmental issues. However:Global warming may enhance ozone depletion global warming produces Tropospheric warming & stratospheric cooling Therefore, if the stratosphere cools, then ozone destroying chemistry (e.g. ozone hole), will increase. Ozone depletion and global warming Ozone module prepared by Eugene C. Cordero

13. With ozone depletion, there will be higher rates of UV radiation. More UV radiation rates mean Higher rates of skin cancer Higher amounts of cataracts Possible danger to plant and animal life Recall: Without the ozone layer, life on the Earth’s surface would not exist!!! What are the consequences of an ozone depleted world? Ozone module prepared by Eugene C. Cordero

14. The international community has a plan to phase out CFC’s in the atmosphere. So far, it looks like it’s working! Current predictions indicate that ozone will recover in next 50-100 years. Summary Ozone module prepared by Eugene C. Cordero