ATMS 571: Final Exam Review A’98 Hartmann

Here are some questions that you might find useful in preparation for the final examination. The test will be closed book, so memorize what you need.

1. Why does the stratosphere cool when you add CO2? Use an equation to illustrate.
2. Why do most models predict that midlatitude land areas will become dryer during the summer growing season in a greenhouse gas warmed Earth? What’s the process?
3. How do we know that the carbon dioxide increase over the last few centuries is caused mostly by fossil fuel burning? Give all the scientific arguments you can muster.
4. Why do we believe that northern forests have taken up much of the carbon dioxide released by fossil fuel burning during the last decade?
5. How does having dynamical oceans, as opposed to mixed layer oceans, in model simulations of transient greenhouse gas warming affect the magnitude and spatial distribution of the surface warming? Why?
6. How does the response of the ocean to transient greenhouse warming affect the uptake of carbon by the ocean? Consider: 1) the effect on SST, 2) the effect on mixing, and 3) the effect on biological uptake (i.e. the biological pump).
7. What characteristics of a volcanic eruption determine its potential to affect surface climate changes?
8. Discuss the relative importance of ice sheets, CO2, ice-free land albedo changes, and orbital parameter changes in explaining "observed" climate changes 20,000 and 7,000 years ago.
9. What important things have we learned from trying to model ice ages with GCMs? What questions remain?
10. 6,000 years ago the Sahara was wet. Discuss what external forcing could have contributed to this change and what internal feedbacks might be necessary to get the full amplitude of the transition from dry to wet conditions in the Sahara.
11. Give 2 or 3 reasons why CFCs are important greenhouse gases, even though they are present in only about one millionth the abundance of CO2.
12. Over the last 10 or 20 years, what are the relative contributions to the human-induced greenhouse anomaly from CO2, CFCs, methane and nitrous oxide? How do you expect this to change in the next 50 years or so?
13. What important modifications would you make to the 1930 theory of Milankovitch for how orbital parameter changes affect the progression of ice ages, if any?
14. What is the highest priority for climate research, understanding the forcing or understanding feedback mechanisms? Don’t bother to say both are important, pick one for the sake of argumentation. Give quantitative examples to back up your position.
15. There is some argument about whether the direct forcing of anthropogenic aerosols is a significant term in the forcing of climate, although some papers say that well-mixed greenhouse gases plus human-induced (mostly sulfur) aerosols can explain recent trends in global temperature. Why might the effect of sulfate aerosols be uncertain and why do some say they are a significant negative forcing , while others say they provide only a small forcing of uncertain sign? Who is right?
16. Explain why the response time of the climate system increases as the sensitivity of the system increases, or illustrate this fact with an ordinary differential equation and its solution.