1. Climate Change and Ozone Loss Chapter 18 “We are embarked on the most colossal ecological experiment of all time – doubling the concentration in the atmosphere of an entire planet of one of its most important gases – and we really have little idea of what might happen.” Paul A. Colinvaux

2. Key Concepts How does the Earth’s climate fluctuate What factors affect climate What are the possible effects of global warming What can humans do about potential climate change How are human activities affecting the ozone layer What can humans do about changes in the ozone layer

3. Past Climate Change Past global temperatures Recent trends in global temperatures Fig. 18-2 pg 447

4. The Natural Greenhouse Effect Greenhouse effect Greenhouse Gases

5. Climate Change and Human Activities Increased use of fossil fuels Deforestation Global warming Melting icecaps and glaciers Coral reef bleaching

6. Projecting Future Changes in Earth’s Climate Climate models (see Spotlight p 457) Apparent influence of human activities Could be natural changes Fig. 18-11 p. 455

7. Factors Affecting Changes in Earth’s Average Temperature Changes in solar output Changes in Earth’s albedo Moderating effect of oceans Clouds and water vapor Air pollution Fig. 18-13 p 458

8. Some Possible Effects of a Warmer World Fig. 18-16 p 461

9. Solutions: Dealing with the Threat of Climate Change Do nothing Do more research Act now to reduce risks No-regrets strategy Options: Fig. 18-20 p 466

10. Removing CO 2 From The Atmosphere Tree plantation Coal power plant Tanker delivers CO 2 from plant to rig Oil rig Crop fieldSwitchgrass field Spent oil reservoir is used for CO 2 deposit CO 2 is pumped down to reservoir through abandoned oil field Abandoned oil field CO 2 is pumped down from rig for Deep ocean disposal = CO 2 deposit = CO 2 pumping Fig. 18-21 p 467

11. Reducing Greenhouse Gas Emissions Rio Earth Summit (1992) Kyoto Treaty (1997) Some US CO 2 Reductions

12. Ozone Depletion in the Stratosphere Fig. 18-26, p 473 Terrestrial life Reduce sunburn Prevents tropospheric ozone Importance of Ozone

13. Ozone Depleting Chemicals Chlorofluorocarbons (CFC’s) Halons Methyl bromide Carbon tetrachloride Methyl chloroform Hydrogen chloride

14. Seasonal Thinning at the Poles Ozone thinning (hole) Fig. 18-30 pg. 475 Polar vortex

15. 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 yield and decline in productivity

16. Solutions: Protecting the Ozone Layer CFC substitutes Technofixes Montreal Protocol Fig. 18-33 pg. 479