1. Class #35: Friday, November 19, 2010 1 Class #35: Friday, November 19 Human Influences on Climate

2. Class #36: Monday, November 22, 2010 2 Global Warming is a fact!!! Over the past 2 decades the global average surface temperature has increased noticeably. A trend involves a steady change in one direction—upward for global average temperature. Not every location and/or every region shows the identical pattern.

3. More observations of global warming Widespread retreat of nonpolar glaciers Thinning of arctic sea ice—40% Decreased N Hemisphere snow cover Increase of global mean sea level Longer growing season in NH Shortened duration of ice cover on NH lakes Class #36: Monday, November 22, 2010 3

4. 4

5. 5

6. 6

7. 7

8. 8

9. 9

10. 10

11. Feedback: change leads to change leads to more change Positive feedback mechanism: reinforces (enhances) the original trend (change) Negative feedback mechanism: damps out an existing trend (change) Example of a positive feedback mechanism: warming, evaporation, water vapor, warming Class #36: Monday, November 22, 2010 11

12. More climate feedback mechanisms Example of a negative feedback mechanism: warming, evaporation, water vapor, cloud, cooling Another positive feedback mechanism: –Called the ice/albedo feedback mechanism –Cooling, more ice, higher albedo, more cooling –Warming, less ice, lower albedo, more warming Class #36: Monday, November 22, 2010 12

13. Class #36: Monday, November 22, 2010 13

14. Forest fires produce carbon monoxide Fig. 15-3, p. 444 Class #36: Monday, November 22, 2010 14

15. Air Pollution Air pollutants are aerosol particles (liquids and solids) and gases that, in high concentrations, seriously affect the lives of people and animals, harm plants, or threaten ecosystems. Air pollutants can come from natural sources (volcanoes, forest fires, dust storms) or human activities (anthropogenic sources) Class #36: Monday, November 22, 2010 15

16. Anthropogenic sources of air pollution Transportation: motor vehicles, aircraft, ships Energy generation: electricity generation Industry: smelting, dry cleaning, manufacturing Home heating Carbon dioxide can be considered a pollutant Class #36: Monday, November 22, 2010 16

17. Primary air pollutants Emitted directly by sources Carbon monoxide, a gas, incomplete combustion, can cause death in small concentrations, emitted by vehicles and defective heating devices Lead, a particulate, brain damage, in some paints and treated gasoline, outlawed now Class #36: Monday, November 22, 2010 17

18. More primary air pollutants Oxides of sulfur, sulfur dioxide and sulfur trioxide, respiratory irritant, emitted in burning fossil fuels containing sulfur Oxides of nitrogen, nitric oxide and nitrogen dioxide, pulmonary problems, emitted by high-temperature combustion of fossil fuels in transportation and electric energy generation Class #36: Monday, November 22, 2010 18

19. More primary air pollutants Hydrocarbons, also called volatile organic compounds, or VOCs –Some are carcinogens –Are made up of hydrogen and carbon –Emitted by motor vehicles, dry cleaning Particulates, small particles –Smallest are most dangerous to lungs Class #36: Monday, November 22, 2010 19

20. Secondary air pollutants Are produced in chemical reactions with primary air pollutants Present harder-to-solve problems than primary air pollutants Include acid deposition and photochemical oxidants (smog)/ozone Class #36: Monday, November 22, 2010 20

21. Acid deposition Can be acid rain, snow, fog, dew, or dry Formed when oxides of nitrogen and sulfur combine with water vapor or liquid water to produce nitric acid and sulfuric acid In water, allows toxic heavy metals to leach out and contaminate drinking water Damage to structures, make lakes toxic Class #36: Monday, November 22, 2010 21

22. Fig. 15-4, p. 445 Class #36: Monday, November 22, 2010 22

23. pH level of rain in 2001 Fig. 15-5, p. 446 Class #36: Monday, November 22, 2010 23

24. Photochemical oxidants/smog/ozone Irritates eyes, nose, throat; causes coughing chest pain, and shortness of breath, aggravates asthma and bronchitis Forms when sunlight acts on a combination of hydrocarbons, oxides of nitrogen, and oxygen Ozone is the main component, with PAN and formaldehyde Class #36: Monday, November 22, 2010 24

25. Table 15-1, p. 445 Class #36: Monday, November 22, 2010 25

26. Table 15-2, p. 445 Class #36: Monday, November 22, 2010 26

27. Fig. 15-7, p. 448 Class #36: Monday, November 22, 2010 27

28. Fig. 15-6, p. 447 Class #36: Monday, November 22, 2010 28

29. Fig. 15-8, p. 449 Class #36: Monday, November 22, 2010 29

30. Class #36: Monday, November 22, 2010 30

31. Class #36: Monday, November 22, 2010 31

32. Class #36: Monday, November 22, 2010 32

33. Class #36: Monday, November 22, 2010 33

34. Class #36: Monday, November 22, 2010 34

35. Class #36: Monday, November 22, 2010 35

36. Class #36: Monday, November 22, 2010 36

37. Class #36: Monday, November 22, 2010 37

38. Class #36: Monday, November 22, 2010 38

39. Class #36: Monday, November 22, 2010 39

40. Class #36: Monday, November 22, 2010 40

41. Class #36: Monday, November 22, 2010 41

42. Class #36: Monday, November 22, 2010 42

43. Class #36: Monday, November 22, 2010 43

44. Class #36: Monday, November 22, 2010 44

45. Class #36: Monday, November 22, 2010 45

46. Fig. 15-1, p. 442 Class #36: Monday, November 22, 2010 46

47. Fig. 15-22, p. 465 Class #36: Monday, November 22, 2010 47

48. Primary air pollutants Emitted directly by sources Carbon monoxide, a gas, incomplete combustion, can cause death in small concentrations, emitted by vehicles and defective heating devices Lead, a particulate, brain damage, in some paints and treated gasoline, outlawed now Class #37: Monday, November 29, 2010 48