2. Dendrochronology is the study of: a. the ice ages b. annual growth rings of trees c. time history of past climatic conditions d. fossil pollen 3. The higher the ratio of oxygen 18 to oxygen 16 in the shells of organisms that lived in the sea during the geologic past, the ____ the climate at that time. a. colder b. warmer c. wetter d. drier 4. Which of the following is not true? a. oxygen 16 evaporates more readily from the ocean than oxygen 18 b. oxygen 16 and oxygen 18 are found in roughly equal amounts in ocean water c. the nucleus of oxygen 18 contains two more neutrons than the nucleus of oxygen 16 d. both oxygen 16 and oxygen 18 are found in the shells of marine organisms 5. A high concentration of oxygen 16 found in the ice caves of Antarctica and Greenland would indicate ____ at the time the ice was formed. a. cold air temperatures b. mild winters c. intense ultraviolet radiation d. the caves were under the ocean 7. Evidence suggests that throughout much of the earth's history, the global climate was: a. warmer than it is today b. colder than it is today c. about the same temperature as it is today d. more variable than it is today 8. Which of the following has been used to reconstruct past climates? a. analysis of air bubbles trapped in ice b. study of documents describing floods, droughts and crop yields c. the ratio of oxygen 18 to oxygen 16 in the shells of marine organisms d. study of geologic formations e. all of the above 9. Presently glaciers cover ____ of the earth's surface. a. about 10 percent b. less than 1 percent c. approximately two thirds d. none 11. Thick sheets of ice advanced over North America as far south as New York as recently as: a. 1816 ("the year without a summer") b. 1550 c. 18,000 to 22,000 years ago d. 2 million years ago, at the beginning of the Pleistocene epoch 13. Over the past 100 years or so, it appears that average global temperatures have: a. increased slightly b. fluctuated widely but shown no overall change c. decreased slightly d. remained constant 17. The "year without a summer" (1816) may have been caused by: a. soot from coal fires b. particulate matter and gases from volcanoes c. a dust cloud produced when a meteorite collided with the earth d. deforestation 22. Plate tectonics "explains" certain climatic changes by showing that these changes may be related to: a. mountain building b. the amount of CO2 and H2O released into the atmosphere c. the paths taken by ocean currents d. the position of the continents e. all of the above 23. The Milankovitch Theory proposes that climatic changes are due to: a. variations in the earth's orbit as it travels through space b. volcanic eruptions c. changing levels of CO2 in the earth's atmosphere d. particles suspended in the earth's atmosphere 24. During a period when the earth's orbital tilt is at a minimum, which would probably not be true? a. there should be less seasonal variation between summer and winter b. more snow would probably fall during the winter in polar regions c. there would be a lesser likelihood of glaciers at high latitudes d. there would be less seasonal variations at middle latitudes 25. Precession of the equinox refers to: a. changes in the shape of the earth's orbit as the earth revolves around the sun b. changes in the tilt of the earth as it orbits the sun c. changes in the seasons, especially from winter to summer d. the wobble of the earth on its axis 26. The Milankovitch cycles in association with other natural factors explain how glaciers may advance and retreat over periods of: a. hundreds of millions of years b. several million years c. hundreds of thousands of years d. ten thousand years to one hundred thousand years e. hundreds of years 29. Large volcanic eruptions with an ash veil that enters the stratosphere, tend to ____ at the surface. a. increase temperatures b. increase precipitation c. decrease temperatures d. have no effect 31. It now appears that if global temperatures continue to rise, the oceans: a. will increase the amount of CO2 in the atmosphere b. will reduce the amount of CO2 in the atmosphere c. could increase or reduce the amount of CO2 in the atmosphere d. will have no effect on atmospheric CO2 concentrations 34. Studies reveal that during colder glacial periods, CO2 levels ____ during warmer interglacial periods. a. were higher than b. were lower than c. were about the same as d. were more variable than 36. An increase in atmospheric CO2 concentrations will most likely lead to ____ in the troposphere and ____ in the stratosphere. a. warming, warming b. cooling, warming c. warming, cooling d. cooling, cooling 37. It is now known that, overall, clouds: a. have a net warming effect on climate b. have a net cooling effect on climate c. have no net effect on climate d. are the single most important feature in determining climate 38. The most recent warming trend experienced over the Northern Hemisphere could be the result of: a. increasing volcanic eruptions b. light colored particles in the stratosphere c. increasing levels of CO2 d. a decrease in the energy emitted by the sun e. an observed decrease in snow cover 40. Which of the conditions below would most likely produce warming at the earth's surface? a. increase the amount of low-level global cloudiness b. increase the amount of sulfur-rich particles in the stratosphere c. decrease the energy output of the sun d. increase the amount of global snow cover e. increase the amount of high-level global cloud cover 45. The ocean's conveyor belt circulation is controlled by a. gradients in temperature b. gradients in salinity c. gradients in density d. all of the above Answer Key 1. > b 2. > b 3. > a 4. > b 5. > a 6. > c 7. > a 8. > e 9. > a 10. > c 11. > c 12. > a 13. > a 14. > c 15. > b 16. > c 17. > b 18. > a 19. > b 20. > b 21. > b 22. > e 23. > a 24. > c 25. > d 26. > d 27. > b 28. > d 29. > c 30. > c 31. > c 32. > a 33. > e 34. > b 35. > c 36. > c 37. > b 38. > c 39. > a 40. > e 41. > c 42. > a 43. > b 44. > a 45. > d 46. > Answer not given. 47. > Answer not given. 48. > Answer not given. 49. > Answer not given. 50. > Answer not given. 51. > Answer not given. 52. > Answer not given. 53. > Answer not given. 54. > Answer not given. 55. > Answer not given. 56. > Answer not given. 57. > Answer not given. 58. > Answer not given. 59. > Answer not given. 60. > Answer not given. 61. > Answer not given. 62. > Answer not given.