GEO 302C EXAM 3 Spring 2005
Name_____________________________________
UID______________________________________
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.
Match (one-to-one) the following (1–5) from the list (A–E) below.
E1.
Dansgaard-Oeschger cycles
D2. Heinrich event
A3.
Younger Dryas
B4.
Maunder sunspot minimum
C5.
Little Ice Age
A. A period of sudden big drop in temperature during the
middle of the last deglaciation in the North Atlantic region
B. A period of very few sunspots during 1645–1715 A.D.
C. A period between 1400–1900 A.D. when Europe was
colder than today
D. An interval of rapid flow of icebergs into the North
Atlantic, causing deposition of debris eroded from land
E. 2000–7000-year oscillations recorded in Greenland ice
during glacial intervals
Match (one-to-one) the following names (6–10) from the list (A–E) below.
E6.
C7.
Carbon dioxide
Ozone
B8. Methane
A9.
Sulfate aerosols
D10. Chlorofluorocarbons
A. Suspended fine particles in the atmosphere from SO2
B. A greenhouse gas that comes from cattle, rice fields,
bogs, and wetlands
C. A greenhouse gas that is a main component of smog
D. Synthetic chemicals that can destroy the ozone layer
E. A greenhouse gas that forms plants tissues during
photosysnthesis
D11. The cooling of the tropics in the last glacial period was mainly caused by
A. volcanic eruptions
B. melting of ice sheets
C. weaker Sun
D. lower CO2 and CH4 levels
E. None of the above
C12. The melting of ice sheets over the last 17,000 years can be best determined by
a. counting the sunspot numbers.
b. tracing the footprints of dinosaurs.
c. studying tropical coral reefs far from the polar ice sheets.
d. all of the above.
e. a and b only.
C13. The sunspot numbers
a. are a useful indicator of my mood today.
b. can be used to predict if next week’s weather is good enough for me to play golf.
c. show an 11-year cycle whose longer-term average resembles observed temperature changes during the
20th century.
d. correlate with frequency of large volcanic explosions.
e. are the most important source for pinpointing the past variations of atmospheric carbon dioxide.
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A14. During the Little Ice Age,
a. Mountain glaciers in north Europe advanced.
b. The continental ice sheets in North America advanced.
c. Proglacial lakes moved north.
d. All of the above.
e. None of the above.
D15. 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
D16. The so-called "ozone hole" is observed above:
a. the continent of North America
b. the equator
c. the continent of Australia
d. the continent of Antarctica
e. the continent of Asia
A17.
Over the past 100 years or so, it appears that average yearly global temperatures have:
a. increased slightly
b. fluctuated widely but shown no overall change
c. decreased slightly
d. remained constant
C18.
The Viking colony in Greenland perished during:
a. the Younger Dryas
b. the climatic optimum
c. the Little Ice Age
d. the explosion of Mt. Pinatubo
e. the Industrial Revolution
B19.
The Medieval Climatic Optimum was a relatively _________ period.
a. cold
b. warm
A20.
During the Medieval Climatic Optimum:
a. Nordic people managed to grow wheat along the southern fringes in Greenland.
b. the Bering land bridge formed.
c. alpine glaciers grew in size and advanced.
d. continental glaciers covered large portions of North America.
e. sea level lowered by about 280 ft.
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The above figure shows annual changes (anomalies) of the average global surface air temperature
from 1861 to 2000 relative to the 30-year averaged climate from 1961 to 1990 which is considered to
be the baseline period. Please use this figure when answering Questions 21–25.
A21. Which of the following statements is correct in describing the climate from 1861 to 2000:
a. mostly cold but with an overall warming trend
b. mostly warm but with an overall cooling trend
c. mostly warm but without any trend
d. mostly cold but without any trend
e. none of the above
B22. Which of the following statements is correct in describing the climate from 1976 to 2000:
a. mostly cold but with a strong warming trend
b. mostly warm with a strong warming trend
c. mostly warm but without any trend
d. mostly cold but without any trend
e. none of the above
D23. Which decades represented the warmest decades from 1861 to 2000?
a. 1960s
b. 1970s
c. 1980s
d. 1990s
C24. Which year represented the warmest year from 1861 to 2000?
a. 1996
b. 1997
c. 1998
d. 1999
e. 2000
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B25. Which of the following is correct in describing the overall temperature trend over the past 140
years?
a. a warming by about 1.75°C
b. a warming by about 0.75°C
c. a cooling by about 0.75°C
d. a cooling by about 1.75°C
A26. The climate of the last 1000 years can be characterized as:
a. a Medieval Warm Period, a cold Little Ice Age, and a warming trend since the late 19th century
b. a Younger-Dryas cold spell, a cold Little Ice Age, and a warming trend since the late 19th
century
c. a mid-Holocene maximum, a Medieval Warm Period, and a cold Little Ice Age
d. a predominantly warm period
e. all of the above.
D27. The climate of the last 18000 years can be characterized as:
a. mostly cold with relatively short warm periods
b. mostly cold but with an overall warming trend
c. mostly warm but with very strong glacial periods
d. a and b only
e. c only
B28. The millennial-scale oscillations are most pronounced in
a. δ18O records in the North Atlantic sediments
b. δ18O records in Greenland ice cores
c. δ18O records in Antarctic ice cores
E29. The recent global warming trend is consistent with
A. decreasing snow cover in the northern hemisphere
B. increasing global sea level
C. retreating mountain glaciers
D. lengthening the growing season
E. all of the above
B30. The longest instrument records of regional temperature come from
a. Antarctica
b. North America
c. Australia
d. South America
e. Greenland
C31. Evidence of millennial oscillations from North Atlantic sediments includes
a. the amount of ice-rafted debris
b. the percentage of polar foraminifera
c. both a and b
A32. Were changes in the intensity of summer monsoons in the last 17,000 years controlled by orbital
insolation?
a. Yes.
b. No.
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C33. The reason that summer temperatures at high northern latitudes were warmer 6000 years ago
than they are today is because
a. summer insolation values were higher than today
b. low-albedo spruce forest expanded northward into high-albedo tundra
c. both a and b
A34. Millennial-scale oscillations were ________ when glacial ice sheets existed, but _________
during interglacial climates like today.
a. larger, smaller
b. smaller, larger
B35. As marine δ18O values become more _________ because of increased extraction of 16O-rich water
vapor, δ18O values in ice cores become more __________, indicating a ________ climate.
a. negative, positive, colder
b. positive, negative, colder
c. negative, positive, warmer
d. positive, negative, warmer
A36. Primary factors affecting the δ18O values of ice cores include
A. the temperature of snow over the ice sheets
B. the color of clouds in the tropics
C. the percentage of polar species
D. the sources of ice-rafted debris
E. the size of the dust particles
B37. The reason that it is difficult to correlate millennial oscillations in records from different regions
is because of
A. lack of these oscillations in regions other than Greenland
B. uncertainties in dating
C. infrequent Heinrich events
D. irregular Dansgaard-Oeschger cycles
E. massive iceberg influxes to the North Atlantic
D38. The reason that long-melted ice sheets complicate attempts to measure modern changes in sea
level is because
A. bedrock rises in areas formerly covered by thick ice
B. bedrock sinks in regions surrounding the former ice sheets
C. ocean basins sink under the added weight of meltwater
D. all of the above
D39. Possible causes of millennial-scale oscillations include
A. natural oscillations of ice margins
B. interactions within the climate system
C. responses to solar variations
D. all of the above
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For Questions 40-50, answer true (a) or false (b).
A40. Large volcanic explosions and major El Nino events cause short-term changes that can be large
enough to be detected in the instrumental temperature record but leave the long-term baseline
trend unaffected.
A41. 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.
A42. 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 thousand years.
B43. The “Global Warming” is mainly caused by the formation of the “Ozone Hole”.
A44. About half of the carbon dioxide added to the atmosphere by human activities remains in the air.
B45. The ozone depletion is essentially a problem over the Antarctic polar region, so it does not affect us
in the U.S.
B46. The clear connection between CFCs and ozone depletion caused so much alarm that the world’s
nations signed a Kyoto Protocol in 1987 to restrict CFC emissions.
B47. The concentration of carbon dioxide in the Earth’s atmosphere is not known accurately and this
fuels the debate about global warming.
A48. The USA leads countries of the world in terms of carbon dioxide produced per person.
B49. Today’s atmospheric CO2 level is lower than the preindustrial level.
A50. Cloud cover in both hemispheres has increased during the 20th century.
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