1. Climate Change and Ozone Loss Chapter 21

2. Key Concepts  Changes in Earth’s climate over time  Factors affecting climate  Possible effects of global warming  Adapting to climate change  Human impacts on the ozone layer  Protecting and restoring the ozone layer

3. The Earth’s Natural Greenhouse Effect Certain gases in the atmosphere absorb heat and warm the lower atmosphere. A natural process called the greenhouse effect warms the lower troposphere and surface. A large process also takes place at the earth’s surface due to heat absorbed by surface water. The earth’s average surface temperature is about 15 degrees Celsius.

4. The Greenhouse Effect  Greenhouse effect  Greenhouse gases (Refer to Table 21-1 p. 464) Fig. 6-14 p. 110

5. Climate Change and Human Activities  Increased use of fossil fuels  Deforestation  Global warming  Melting icecaps and glaciers  Rising sea level

6. Projecting Future Changes in Earth’s Climate  Climate models  Apparent influence of human activities  Could be natural changes

7. 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

10. Past Climate Changes  Past global temperatures  Recent trends in global temperatures Fig. 21-2 p. 463

19. Some Possible Effects of a Warmer World Fig. 21-12 p. 475

20. 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  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. 21-13 p. 476

21. Solutions: Dealing with the Threat of Climate Change Options  Do nothing  Do more research  Act now to reduce risks  Precautionary principle Fig. 21-17 p. 479

23. Reducing Greenhouse Gas Emissions  Kyoto Treaty (1997)  Other reductions in CO 2  U.S. withdraws from Kyoto Treaty (2001)

24. 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

25. Ozone Depleting Chemicals  Chlorofluorocarbons (CFCs)  Halons  Methyl bromide  Carbon tetrachloride  Methyl chloroform  Hydrogen chloride

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

27. Ozone Depletion in the Stratosphere Fig. 21-21 p. 484 ClO

28. Seasonal Ozone Layer Thinning at the Poles  Ozone thinning (hole)  Polar vortex

29. Skin Cancers Fig. 21-25 p. 487

30. Solutions: Protecting the Ozone Layer  CFC substitutes  Montreal Protocol  Copenhagen Protocol Fig. 21-27 p. 489