GEO 302C EXAM 3 Fall 2002 Name_____________________________________



You may not refer to any other materials during the exam. For each question (except otherwise explicitly stated), select the best answer for that question. Read all choices before selecting an answer and make sure your choice answers the question asked.


1. Over the past twenty years or so, the size of the Antarctic ozone hole has increased to approximately as large as the area of

a. Austin

b. Texas

c. Mexico

d. North America

e. the Pacific Ocean

2. Near the Earth’s surface _________ is a major component of urban smog, but in the stratosphere it protects life on Earth from harmful UV radiation.

a. O

b. O2

c. O3

d. CO

e. OH-

3. The three largest reservoirs of carbon in the earth’s climate system in the decreasing order of mass are:

a. Sedimentary rocks, oceans, and soil organic matter

b. Oceans, soil organic matter, and atmosphere

c. Oceans, atmosphere, and soil organic matter

d. Atmosphere, land biota, and marine biota

e. Soil organic matter, land biota, and marine biota

4. During _________ carbon dioxide and water vapor are chemically converted into glucose. During ________ oxygen is combined with glucose to chemically release energy for movement, growth, and maintenance.

a. photosynthesis, respiration

b. respiration, forest fires caused by lightning

c. photosynthesis, transpiration

d. photosynthesis, decomposition

e. transpiration, decomposition


5. Two natural sources of atmospheric carbon dioxide are:

a. photosynthesis and respiration

b. respiration and forest fires caused by lightning

c. photosynthesis and transpiration

d. photosynthesis and decomposition

e. transpiration and decomposition

6. Which of the following is not a greenhouse gas?



C. CH4

D. O3

E. CO2

7. Convection causes circulation of material because hot, light material rises and cold, dense material sinks. This process is occurring in the Earth’s

a. atmosphere

b. hydrosphere

c. asthenosphere

d. all of the above

e. a and b only

8.  Which of the following is in the correct sequence from long to short term effects on climate?

A. eccentricity – mountain building – El Nino – seasonal changes in monsoon intensity

B. plate tectonics – Earth’s orbital parameters – ENSO – seasonal changes in latitudinal distribution of insolation

C. mountain building – the Southern Oscillation – precession - seasonal changes in latitudinal distribution of insolation

D. eccentricity – obliquity – precession – the ocean conveyor belt – ENSO

E. both B and D are correct

9. Which of the following is NOT true about the Milankovitch Cycles?

a. They explain glacial and interglacial intervals during the current Icehouse climate period.

b. One part of the cycle is the change in the tilt of the Earth about every 40,000 years.

c. One part of the cycle is the change in the shape of the Earth’s orbit over time scales of 100,000 years.

d. The cycles have been supported by the trends of atmospheric CO2, CH4, and temperature as recorded in the Antarctic ice core.

e. One part of the cycle is the wobbling of the spin axis about every 10,000 years.


10. Which of the following is most likely to affect both Texas and China:


b. ozone depletion

c. global warming

d. smog

e. all of the above

11. The fact that the concentration of the atmospheric carbon dioxide is lower during the Northern Hemisphere summer than during the Northern Hemisphere winter is because

a. ultraviolet radiation breaks down carbon dioxide during the summer.

b. acid rain destroys leaves and so the photosynthesis rate is reduced.

c. most land is located in the Northern Hemisphere and that green vegetation uptakes carbon dioxide for photosynthesis during the Northern Hemisphere summer.

d. all of the above.

e. none of the above. 


12. The water vapor-temperature rise feedback is a positive feedback because the initial _______ in temperature is _______ by the addition of more water vapor.

a.  increase, reinforced

b.  decrease, unaltered

c.  increase, weakened

d. decrease, reinforced


13. The present-day short-term global carbon cycle

a.    is out of balance due to human activities

b.    will likely be back in balance by the year 2100 due to plate tectonic compensations

c     is kept in balance by plate tectonics and weathering

d.    is independent of the global oxygen cycle

e.    all of the above

For Questions 14-18, matching

B 14. Volatile organic compounds             a. A by-product of rice cultivation and enteric

                                                                       fermentation in domesticated livestock.

E 15. Chlourofluorocarbons                      b. Help create tropospheric ozone

D 16. Dimethylsulphides (DMS)                c. Photosynthesis starting material

C 17. Carbon dioxide                               d. Help form cloud condensation nuclei

A 18. Methane                                          e. Help destroy stratospheric ozone


19. Which of the following best describes photosynthesis?

A.      CO2 + H2O à sunlight + chlorophyll

B.      CO2 + H2O à O2 + silicon-based life forms

C.      CO2 + H2O +sunlight à O2 + CH2O

D.      CaCO3 + CO2 + H2O à Ca+ +2HCO3-

E.      Carbon dioxide + water à oxygen + calcium carbonate


20. The rise of greenhouse gases and global temperatures is a difficult problem to deal with in that

a. carbon dioxide is odorless and colorless and one year’s rise doesn’t affect us personally

b. many of the unwanted side effects are yet to come

c. the average person and the average policy maker can more easily conceptualize polluted water than they can understand the workings of the global carbon cycle

d. all of the above


21. Fossil fuel is a __________ energy source, because coal, oil, and gas deposits take _______ of years and specific environmental conditions to form, and the mining of these deposits brings these materials back to the surface much more ______ than natural processes.

a. renewable, millions, rapidly

b. nonrenewable, millions, rapidly
c. nonrenewable, hundreds, slowly

d. renewable, hundreds, rapidly

e. nonrenewable, thousands, slowly

22. Over the last 250 years or so, the atmospheric CO2 concentration has increased by about ____ above the concentration of 275 ppmv in 1750.

a. 1%

b. 3%

c. 10%

d. 30%

e. 100%

23. Over the past two decades or so, the atmospheric concentration has increased by about ____ per year.

a. 0.5 ppmv

b. 1.5 ppmv

c. 5 ppmv

d. 10 ppmv

e. 15 ppmv

For Questions 24-33, answer true (a) or false (b).


A 24. Milutin Milankovitch first proposed in the 1930s that changes in climatic cycles of glacial-interglacial periods were initiated by variations in the Earth’s orbital parameters.


A 25. P. Crutzen, M. Molina and F. Rowland are the three atmospheric scientists who were awarded the Nobel Prize for their role in determining the chemical processes causing the stratospheric ozone depletion.


A 26. The natural greenhouse effect is not just a "good thing", it is essential to life on Earth. However, the enhanced greenhouse effect due to human activities could raise the temperature of Earth above that experienced by the planet in the last several hundred thousand years.


B 27. The terms "Ozone Depletion" and "Global Warming" refer to the increase in temperatures due to the depletion of ozone in the atmosphere.


A 28. Much of the carbon dioxide added to the atmosphere by human activities is absorbed by the oceans but about half remains in the air.


B 29. The ozone depletion is essentially a problem over the Antarctic polar region, so it does not affect us in the U.S.


B 30. Greenhouse gases act mostly on incoming solar radiation, and this is called the greenhouse effect.


B 31. The concentration of carbon dioxide in the Earth’s atmosphere is not known accurately and this fuels the debate about global warming.


A 32. The USA leads countries of the world in terms of carbon dioxide produced per person.


A 33. Modern general circulation models predict that by 2100 the globally averaged surface air temperature will increase by several °C relative to the current value. The largest warming is predicted to occur at night, during winter, over continents, and near poles.


34. Two examples of human activities that can explain the steady increase in the atmospheric carbon dioxide concentration since the Industrial Revolution are:

A. burning fossil fuels and cutting trees

B. using hydroelectric power and growing trees

C. using nuclear energy and collecting solar energy

D. none of the above


35. Below are two feedback processes that occur in the atmosphere.

(a) temperature rises à cloud cover increases à clouds emit more downward infrared radiation à surface warming.

(b) temperature rises à cloud cover increases à clouds reflect more solar radiation back to space à surface cooling.

Which of the following is correct?

A. (a) is negative feedback and (b) is positive feedback

B. (a) is positive feedback and (b) is positive feedback

C. (a) is positive feedback and (b) is negative feedback

D. (a) is negative feedback and (b) is negative feedback


36. Which of the following is NOT a property of chlorofluorocarbons:
A. release chlorine atoms that then deplete the ozone layer
B. break down by strong ultraviolet light in the stratosphere
C. are used as refrigerants, solvents, and foam blowing agents

D. consist of chlorine, fluorine, and carbon
E. are natural by-products of life processes and combustion


37. Which of the following is NOT a potential way to enhance carbon dioxide sinks?
A. planting more trees
B. increasing crop areas
C. reducing frequency of forest fires
D. building more roads in forests for summer retreat


38. The observed global mean surface air temperature has increased by about 0.6°C since the late 19th century. This warming trend is consistent with

A. a decreasing trend in the Northern Hemisphere snow cover

B. an overall increasing trend of the U.S. sea level

C. an increasing trend of the atmospheric carbon dioxide

D. all of the above.

E. none of the above


39. An example of how size doesn’t necessarily matter in terms of enormous reservoirs playing a small role in global cycles is

a.      the large amount of carbon stored in ancient marine limestones (chemical formula: CaCO3) has little effect on the modern carbon cycle because most of these limestones are buried below the surface of the Earth and because the limestones that are at the surface weather at a relatively slow rate

b.      the terrestrial atmosphere is one of the itty-bittiest global reservoirs of water, yet it has phenomenal powers in controlling weather and the movement of water through the hydrological cycle

c.      Earth’s core is pure carbon, yet we’ll never see any of it go into the atmosphere in our lifetimes

d.      all of the above

e.      a and b only


40.   The reason for all of the concern about the state of the global carbon cycle is the fact that

a.      A new record high in Earth history for atmospheric CO2 levels is achieved each year

b.      carbon occurs in the atmosphere bonded to oxygen as a gas and this gas is one of the greenhouse gases that can dramatically influence Earth’s climate

c.      humans have been pumping carbon into the atmosphere by their use of oil, gas, and coal; by their manufacturing of cement; and by their destruction of forests.

d.      b and c only

e.      none of the above – since the carbon cycle is linked to the oxygen cycle, and since the life activities of humans and other non-photosynthetic organisms regulate the oxygen cycle, the concern is largely overblown.