Final Exam - Part II
May 11, 1999

Part I: True/False (5 pts each)

True

The variety of climatic zones that one observes on a mountain are due primarily to differences in temperature and rainfall amounts.

False

Ships logs from the 15th and 16th centuries are used to reconstruct past climates because of the accuracy of their meteorological observations.

True

Latitude is an important climatic attribute because of the effect is has on the amount of solar radiation reaching the Earth's surface.

True

The last glacial period occurred during the Cenozoic Era, the Quaternary Period, and the Pleistocene Epoch.

True

Studies reveal that during colder glacial periods, CO₂ levels were lower than during warmer interglacial periods.

True

Climate models predict that if average global temperatures rise by about 2.5^o C, average global precipitation will increase.

False

Dendroclimatology is the study of the accumulation of rocks and debris carried or deposited by glaciers.

True

The holocene epoch began about 10,000 years ago.

True

Many scientists believe that the changes in energy involved in the Milankovitch cycles may not be sufficiently large on their own to have caused the huge climatic shifts between glacial and interglacial conditions.

False

The Sahara region was much drier than today during the last Ice Age.

True

Recent general circulation model studies have suggested that the warming due to enhanced greenhouse effect is likely to occur more rapidly over land than the over open seas.

False

Seasons are caused by the eccentricity of the Earth's orbit around the sun and the fact that the Earth is closer to the sun in summer than the winter.

False

The "ITCZ" is near the North Pole.

Part II: Multiple choice questions (5 pts each)

1. Changes in the Earth's obliquity refer to:

   • changes in the shape of the Earth's orbit as it revolves around the sun
   • changes in the tilt of the Earth as it orbits the sun
   • changes in the length of the seasons, especially autumn and spring
   • the precession of the earth on its rotation axis

2. During the Pleistocene epoch:

   • continental glaciers continuously covered large parts of North America and Europe
   • it was much warmer than it is now
   • continental glaciers alternately advanced and retreated over large portions of North America and Europe
   • tropical vegetation was growing over vast regions of the Central Plains of North America

3. The Milankovitch Theory proposes that climatic changes are due to:

   • variations in the Earth's orbit as it travels through space
   • volcanic eruptions
   • changing levels of CO₂ in the Earth's atmosphere
   • particles suspended in the Earth's atmosphere

4. A rainshadow desert is normally found:

   • in the center of a large surface anticyclone
   • on the back (western) side of a large thunderstorm
   • in polar regions where the air is cold and dry
   • in the center of the ITCZ
   • on the downwind side of a mountain range

5. Oxygen isotope analysis cannot be used to identify changes in temperature in:

   • sea-shells
   • ice cores
   • ocean floor sediment cores
   • rocks and minerals

6. The end of the last Ice Age promoted the following changes to the landscape:

   • melting of large amounts of ice
   • rise of sea level
   • prolonged rise of those land areas that had been weighted down by the masses of ice
   • advances of forests to regions with tundra and grassy plains
   • all of the above

7. During the Little Ice Age:

   • the climatic optimum occurred
   • the Bering land Bridge formed
   • alpine glaciers grew in size and advanced
   • continental glaciers covered large portions of North America
   • sea level lowered by about 280 ft

8. A negative feedback mechanism:

   • acts to reinforce an initial change
   • acts to weaken or oppose and initial change
   • will cause a positive change
   • will cause a negative change

Part III: Short Answer (10 pts each)

1. Name two possible short-term (1-3 years) impacts of explosive volcanic eruptions on the Earth's climate.

2. In addition to carbon dioxide, name three other gases that may contribute to the problem of global warming.

3. Ice cores from Antarctica and Greenland are a powerful tool for examining past climates. Name three types of climate information contained in ice core layers.

Part IV: Longer Answers (20 pts each)
Please answer at least 4 of the following 5 questions. Answers should be 1 to 3 complete sentences.

1. Explain the difference between the concepts of weather and climate.

2. Explain how the annual growth of trees can be used to reconstruct past climates.

3. What climate condition allowed for the migration of human populations from Asia to North America? Why? (be complete in your answer).

4. Between 12,800 and 11,500 years ago a short but severe cold spell, named the ``Younger Dryas'' event, occurred. Explain why this event is important to the understanding of climate variations.

5. Give two specific examples in which climate fluctuations can affect human affairs in two of the following four areas: a) Agriculture, b) species and natural areas, c) water resources, d) coastal areas.