Geog 372 First Midterm

GEOG 372 GLOBAL CLIMATE CHANGE

FALL 2009 (Oct. 1) Name _______________________

FIRST MIDTERM (Worth 15% of your final grade)

MULTIPLE CHOICE. Choose the best answer, if more than one appears correct. (1 pt ea) Please read each answer carefully. Often one word changes the meaning of the question or answer.

1. Which of the following provides both chronological (time) and climatic information?

a. tephra c. tree rings (dendroecology) e. thermohaline circulation

b. pollen d. lake levels

2. The greenhouse effect is caused by

a. selective absorption of specific wavelengths of solar radiation by certain gases.

b. selective absorption of gases by infrared radiation

c. absorption of certain wavelengths of infrared radiation by specific atmospheric gases

d. the absorption and reradiation of heat by certain surface materials

e. the absorption of ultraviolet radiation by certain gases in the atmosphere

3. The shape and depth of ocean basins are controlled by ______ and influence rates of _______ .

a. rates of sea floor spreading; carbon dioxide emitted by volcanoes d. tectonic uplift; sea surface temperature change

b. continental drift; rock weathering e. wandering of the poles; sea level change

c. sea floor spreading and continental drift; carbon dioxide released to atmosphere, and sea level change.

4. Positive feedback is occurring when

a. the effects of a process, such as ice melting, enhances that same process and keeps it going.

b. the effects of a process, such as ice melting, causes the process to be inhibited, slowing it down or stopping it.

c. a process, such as ice melting, starts occurring due to an external forcing mechanism.

d. a lag time occurs in response to a previous forcing.

e. None of the above is correct.

5. Which of the following is NOT a primary forcing mechanism for global climate change?

a. variations in solar radiation c. changes in the earth’s orbit and tilt e. major mountain uplift

b. continental drift d. changes in the earth’s albedo

6. The amount of energy emitted by the sun

a. is proportional to its temperature of 5800 K c. is not as great in the visible range as are the earth’s emissions

b. is far greater in the UV range than IR range. d. is greatest in the Northern Hemisphere summer.

7. The major greenhouse gases in the atmosphere today include

a. Nitrogen, oxygen, helium, and hydrogen d. CO ­2, CH 4, H 2O, N 2O, and CFCs

b. Carbon dioxide, methane, water vapor, and argon e. Carbon dioxide, nitrogen, methane, and water vapor.

c. Primarily carbon dioxide.

8. Latitude is the most important control on climate variation from place to place because

a. intensity of solar radiation varies from highest at the equator to lowest at the poles.

b. global scale differences in temperature are driven by differences in solar angle.

c. variations in solar radiation strongly influence climate in terms of temperature and precipitation, seasonality of climate, and plant assemblages from place to place.

d. differences in solar radiation received at different latitudes drives atmospheric circulation differences from place to place.

e. All of the above are correct.

9. Which of the following is NOT a major control on climate distribution from place to place?

a. general atmospheric circulation

b. continentality, distribution of continental masses and relief

c. proximity to water, especially oceans

d. tectonic activity

e. elevation and topography

10. Which of the following is the general name of the Ice Ages?

a. Pleistocene c. Wisconsinan b. Holocene d. Eemian e. Quaternary

SHORT ANSWER. Choose FIVE of the following SEVEN to answer briefly, plus a sketch or diagram where helpful or requested. (3 pts each)

1. Why is Venus so much hotter than the Earth, other than the fact that it’s closer to the sun?

2. What are the major controls on climate distribution from place to place on earth today? List and explain each briefly.

3. Draw and fully label a diagram of the Carbon Cycle, showing interactions of the four spheres.

4. How do feedbacks, positive and negative, play a role in climate? Use examples of each type in your answer.

5. What are the three independent forcing mechanisms that cause climate change over time? Describe each briefly

6. What is the likely role of chemical weathering as the “thermostat” of earth’s climate?

7. Describe the “Faint Young Sun” paradox. With so weak a young sun, why wasn’t the Earth frozen for the first two-thirds of its history?

SHORT ESSAY. Write an essay in one or two paragraphs, using full sentences and proper grammar and spelling. Use diagrams where useful. Be sure to answer all parts of the question. (10 pts)

Discuss the range of proxy indicators used to reconstruct past climate. What are the characteristics of a good proxy for climate? Why, and in what ways, is vegetation a good proxy for climate? What sorts of proxy information can be obtained from lake sediments and shorelines? What sorts of proxy information can be obtained from ocean sediments and shorelines?