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Topics for Today

Topics for Today

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Topics for Today

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  1. Topics for Today • Climate Change: A Global Problem? • Quiz #7 (of 11)!!

  2. Readings for Today May even bleed into Monday. • 3.8 Methane and other greenhouse gases  •  3.10 Responding to science with policy changes •  3.11 The Kyoto Protocol on Climate Change •  3.12 Global warming and ozone depletion

  3. Topics for Monday • Where does the Carbon Go? • The Carbon Cycle http://www.esd.ornl.gov/iab/iab2-2.htm

  4. Readings for Monday • 3.5 The Carbon Cycle

  5. Announcements!!!

  6. Announcements!!!

  7. Bring back your radon disks!!

  8. Announcements! Nice, warm weather… Please remember: Do not wear shorts or sandals to lab!!

  9. Topics for Today • Climate Change: A Global Problem? • Quiz #7 (of 11)!!

  10. Review… The Greenhouse Effect

  11. Q: When will IR cause a molecule to vibrate? A: When there is a dipole moment!

  12. Review Dipole Moment: Unequal distribution of charge! N2?? Does CO2 absorb IR radiation?

  13. DEMO!! CO2 N2

  14. What makes greenhouse gases more potent? N2O HCFCs CH4 CH4 CFCs O3 HFCs CO2 H2O

  15. 3) How efficiently can the molecule absorb IR? 1) Atmospheric Lifetime 2) Atmospheric Concentration

  16. 3) How efficiently can the molecule absorb IR? 1) Atmospheric Lifetime 2) Atmospheric Concentration

  17. CO2 bending and stretching… CO2 has only 3 vibrations • Summary • Symmetric Stretch • Asymmetric Stretch • Bend 1 • Bend 2

  18. This is due to the more complicated SHAPE CFCs CFCs have at least 10 possible vibrations!! CFCs are much more efficient at trapping IR than CO2.

  19. 3) How efficiently can the molecule absorb IR? 1) Atmospheric Lifetime 2) Atmospheric Concentration 4) WHERE it absorbs in the IR range!!

  20. Figure 3.16 Water Vapor

  21. CO2 Figure 3.15 in your Text

  22. What about the other gases? CO2 Figure 3.15 in your Text

  23. Absorption %

  24. Absorption %

  25. This range is called the “atmospheric window.” Very little IR is absorbed from 8-12 micrometers!! Reminder: This is 8,000-12,000 nm!!

  26. Where do CFCs absorb?

  27. Micrometers? HCFC 132a www.sstd.rl.ac.uk/srg/srgproj/ircfc/ircfc.htm

  28. HCFC 132a CFCs (and replacements) absorb directly in the atmospheric window!!! 17 10 7 5 2.8 MICROMETERS www.sstd.rl.ac.uk/srg/srgproj/ircfc/ircfc.htm

  29. Where do CFCs absorb? At about 7-11 micrometers!!

  30. 3) How efficiently can the molecule absorb IR? 1) Atmospheric Lifetime So, just how potent are the major GHGs? 2) Atmospheric Concentration 4) WHERE it absorbs in the IR range!!

  31. Global Warming Potential (GWP) • The ability for a gas to trap energy in the atmosphere. Based on an equal mass of CO2 over a specific time period. http://www.ace.mmu.ac.uk/eae/Global_Warming/Older/GWPs.html

  32. GHGs are not the only thing in the atmosphere that change the Earth’s energy balance!!!

  33. Global Warming Potential (GWP) • The ability for a gas to trap energy in the atmosphere. Based on an equal mass of CO2 over a specific time period. http://www.ace.mmu.ac.uk/eae/Global_Warming/Older/GWPs.html

  34. What are the effects of the enhanced greenhouse effect?

  35. Greenhouse gases correlate with warming! CO2 Concentration (ppm) TEMPERATURE CHANGE

  36. Venus’ atmosphere is about 97% CO2 Runaway greenhouse effect! The average temperature is about 900oF! http://hyperphysics.phy-astr.gsu.edu/hbase/solar/venusenv.html

  37. Very thin atmosphere; most of the CO2 is frozen in the ground… The average temperature is about -60oF!

  38. CO2 Concentration (ppm) TEMPERATURE CHANGE

  39. An increase of about 0.8oC over the past century!

  40. So what if the Earth gets a little warmer?? This is an average…

  41. The big problem is NOT necessarily the warming…

  42. Greenhouse gases lead to more energy trapped in the atmosphere.

  43. Overall, the Earth’s natural energy balance is changed The effects of this can can vary…

  44. What are the effects of increased energy in the atmosphere?

  45. Spruce trees in the arctic tundra…

  46. Retreating Glaciers…

  47. The Cascades