1. Climate Change and Ozone Loss
Chapter 21

2. Past Climate Changes Past global temperatures
Recent trends in global temperatures
Fig p. 463

3. The Greenhouse Effect Greenhouse effect Greenhouse gases
Fig p. 110

4. Factors Affecting the Earth’s Temperature
Changes in solar output
Changes in Earth’s albedo
Moderating effect of oceans
Clouds and water vapor
Air pollution

5. Some Possible Effects of a Warmer World

6. Possible Benefits from a Warmer Atmosphere
Less severe winters
More precipitation in some dry areas
Less precipitation in some wet areas
Increased food production in some areas
Expanded population and ranges of some species
Refer to Fig p. 476

7. Solutions: Dealing with the Threat of Climate Change
Options
Do nothing
Do more research
Act now to reduce risks
Precautionary principle

8. Removing CO2 from the Atmosphere
PREVENTION:
Cut fossil fuel use (especially coal)
Shift from coal to natural gas
Improve energy efficiency
Shift to renewable resources
Reduce deforestation
Limit urban sprawl
Slow population growth

9. Removing CO2 from the Atmosphere
Cleanup
Remove CO2 from smokestack & vehicle emissions
Store CO2 by planting trees
Sequester CO2 deep underground
Sequester CO2 in the deep ocean
Use feeds that reduce CH4 emissions by belching cows

10. Reducing Greenhouse Gas Emissions
Kyoto Treaty (1997)
U.S. withdraws from Kyoto Treaty (2001)
Other ideas: setting technological goals
and standards not targets and
timetables

11. Loss of the Ozone Layer: Reasons for Concern
Increased incidence and severity of sunburn
Increase in eye cataracts
Increased incidence of skin cancer
Immune system suppression
Increase in acid deposition
Lower crop yields and decline in productivity

12. Ozone Depleting Chemicals
Chlorofluorocarbons (CFCs)
Halons (used in fire extinguishers)
Methyl bromide (in fumigants)
Carbon tetrachloride (in cleaners)
Methyl chloroform (in cleaners)
Hydrogen chloride (released from space shuttles)

13. Former Uses of CFCs Air Conditioners Refrigerators Spray cans
Cleaners for electronic parts
Sterilizing medical instruments
Fumigants for cargo ships

14. Ozone Depletion in the Stratosphere
Fig p. 484

15. Solutions: Protecting the Ozone Layer
CFC substitutes
Montreal Protocol (cut by 35%)
Copenhagen Protocol (cut much faster
due to ozone
thinning)