Global Greenhouse Effect (steady-state) vs. Global Warming (disturbed steady-state)

Earth’s Energy Balance

Visible and UV light from sun through atmosphere to earth Energy absorbed by earth Infrared light radiated from earth 84% of radiated IR light absorbed by “Greenhouse Gases” Energy in = Energy out

Disturbed Energy Balance Additional carbon dioxide in atmosphere >84% of radiated IR light absorbed by “Greenhouse Gases” Energy out<Energy in Enhanced greenhouse effect

Matter/Radiation Interaction

What’s a Greenhouse Gas?? CH 4 (methane), H 2 O (water), CO 2 (carbon dioxide) NOT N 2 (nitrogen), O 2 (oxygen) A greenhouse gas absorbs IR radiation

Specific Bending and Stretching, CO 2 Figure 3.6

Greenhouse Gases absorb radiation in the IR region For an absorption to occur, the overall charge distribution in the molecule must change. You must be able to make he molecule non-symmetric

Molecular “SHAPE” From 2D Lewis Structures to 3D shapes “ Electron groups around an atom will orient themselves as far apart as possible”

Fig. p.115

Figure 3.10 CO 2 Human Contribution

How much carbon dioxide do you generate when you have an outdoor barbecue?

Two ways to quantify How many? –Particles –Moles of particles What mass? –Atomic weight (isotope average) –Molar mass

Enhanced Global Warming?

Fig. 3.6

Relation between CO 2 and Temperature

Fig. 3.2

True, False or Maybe? 1. Carbon dioxide contributes to an elevated global temperature. 2. The concentration of CO 2 in the atmosphere has been increasing. 3. The increase in CO 2 is due to human activity.

True, False or Maybe? Cont. 4. There has been an increase in average global temperature during the past century? 5. The greenhouse gases generated by human activity are responsible for the temperature increase.

True, False or Maybe? Cont. 6. The average global temperature will continue to increase as human emissions of greenhouse gases increase.

Climate Modeling MANY variables difficult to identify difficult to measure interactions

3.9 Consider This: The CO 2 Emissions-Implications for Policy (page 109)

Homework Read distributed article and identify two questions you would like to have answers to before you could decide to endorse or not endorse the Bush administration’s policy. (TYPED for FRIDAY)