Chapter 3 The Chemistry of Global Warming

1. Chapter 3 The Chemistry of Global Warming Sections 3.4 & 3.8-end

2. Chapter 3; The Chemistry of Global Warming • Global Warming and the Enhanced Greenhouse Effect • Carbon Dioxide Concentrations & Average Global Temperature • Carbon Dioxide Cycle • Molecular Structure (3-D) Shape • Why Some Gases are Greenhouse Gases; while other are not

3. Chapter 3; The Chemistry of Global Warming • Other Greenhouse Gases and Global Warming Potential (GWP) • Molar Mass and Mass Percent • Possible Effects of Global Warming • Global Warming vs. Ozone Hole • Quantitative Aspects

4. Greenhouse Gases Carbon dioxide; CO2 Water; H2O CFC’s Nitrous Oxide; N2O Methane; CH4 NOT Greenhouse Gases Nitrogen; N2 Oxygen; O2 Argon; Ar Gases

5. Different Types of Electromagnetic Radiation Do Different “Things” to Molecule

6. Bond Stretching Molecule Bending Vibrations of Molecules It takes less energy to bend a molecule than stretch a bond.

7. Vibrations of CO2 Molecule Symmetric Stretch Assymmetric Stretch Bending motion Bending motion

8. For a bending or stretching motion to absorb IR radiation; it must change the dipole moment of the molecule - - + Antisymmetric Stretch; IR Active Symmetric Stretch; IR Inactive - - + - - +

9. Electronegativity- Measure of an atom’s attraction for the electrons it shares in a covalent bond.

10. Infrared Spectrum of CO2

11. Infrared Spectrum of Water (H2O) Vapor

12. Greenhouse Gas Requirements • Minimum of 2 atoms needed for stretching bonds • Two atoms must be different in order for vibration to change the dipole moment of molecule • Minimum of 3 atoms needed to bend a molecule

13. Why Argon, Ar, Can Not Be a Greenhouse Gas • Argon is in atomic form. Thus, there is no bond to another atom. So it can’t absorb IR to stretch a bond it doesn’t have. • Argon can’t absorb IR to bend a molecule since a minimum of 3 atoms is needed and it has only 1 atom.

14. Global Warming Potential – Represents the Relative Contribution a Molecule Has in Global Warming • How Long a Molecule in the Troposphere/ Is There a Way to Remove Molecule From Troposphere? • Does the Molecule Absorb in the Window Region? • Amount of Molecule in the Troposphere

15. Global Warming Potential (GWP)

16. IR Spectrum of CO2 and H2O Overlapped Leaves “Window” Region when Neither Absorbs IR Energy

17. Window

18. Increasing the GWP of a Greenhouse Gas • When a different greenhouse gas absorbs in the window region of the IR spectrum; it will have a higher GWP • *Biggest Effect • The higher the tropospheric abundance; higher GWP • The higher the lifetime of the molecule; higher GWP

19. Natural Sources (~40%) Component of Natural Gas Decayed vegetable matter in wetlands Man-made Sources Oil wells Landfills Rice paddies Cattle and sheep Frozen methane hydrate cages Methane; CH4

20. Frozen Methane Hydrate Cages

21. Methane Absorbs at the Edge of Window Region of IR Spectrum

22. Methane Absorbs at the Edge of Window Region of IR Spectrum

23. Manmade Sources Dental/medical Use Fertilizers Burning Biomass/catalytic converters Production of nylon and nitric acid Absorbs in the Window Region of IR Spectrum Nitrous Oxide, N2O; “Laughing Gas”

24. Nitrous Oxide, N2O, Absorbs in the Window Region of the IR Spectrum

25. Nitrous Oxide Absorbs in the Window Region of IR Spectrum

27. Human Contribution of Different Greenhouse Gases to Global Warming

28. Feedback • Positive; Amplifies/reinforces ongoing trend • Negative; Diminish/reverse trend to maintain status quo

29. Possible Impacts of Global Warming • Sea Levels • Forests • Biodiversity • Food Production • Water • Weather • Health

30. Climate Change and Sea Level

33. Early Warning Signs of Global Warminghttp://www.climatehotmap.org/

34. FINGERPRINTS: Direct manifestations of a widespread and long-term trend toward warmer global temperatures http://www.climatehotmap.org/ • Heat waves and periods of unusually warm weather • Ocean warming, sea-level rise and coastal flooding • Glaciers melting • Arctic and Antarctic warming

35. Glacier National ParkAll but 37 of 150 glaciers in the park have melted since 1850.

36. Glacier National Park 1998 1957

37. Global Climate Change Melting permafrost

38. HARBINGERS: Events that foreshadow the types of impacts likely to become more frequent and widespread with continued warming. • Spreading disease • Earlier spring arrival • Plant and animal range shifts and population changes • Coral reef bleaching • Downpours, heavy snowfalls, and flooding • Droughts and fires

40. Coral Bleaching

42. Possible Consequences of Global Warming

43. Ways an Individual Can Help Reduce Global Warming • Reduce use of fossil fuels; car pool, use mass transit, walk, bike • Use energy efficient appliances and light bulbs • Plant trees (Cool house with shade trees) • Use solar energy to heat household as much as possible

44. Fig.03.p158

45. A major point of disagreement of the Kyoto Protocol is that developing countries do not have to cut emissions as much as developed countries. Greenhouse gas emissions are expected to increase faster in developing rather than developed countries

46. Global Warming vs. Ozone Depletion

47. Global Warming vs. Ozone Depletion

48. Global Warming vs. Ozone Depletion