Deck 17: Earths Changing Climate

Question 1

Which of the following statements characterizes oxygen 16 and oxygen 18?

A)Oxygen 16 and oxygen 18 evaporate from ocean water at the same rate.
B)Oxygen 18 contains two more electrons than oxygen 16.
C)Oxygen 16 and oxygen 18 exist in the shells of marine organisms.
D)Oxygen 16 and oxygen 18 occur in roughly equal amounts in ocean water.

Answer 1

C

Question 2

Consider the ratio of oxygen 18 to oxygen 16 in the shells of organisms that lived in the sea during the geologic past. Which of the following describes the relationship between this ratio and the climate at that time?

A)the higher the ratio, the drier climate at that time
B)the higher the ratio, the wetter climate at that time
C)the higher the ratio, the colder climate at that time
D)the higher the ratio, the warmer climate at that time

Answer 2

C

Question 3

Which of the following has been used to reconstruct past climates?

A)study of the Earth's mantle
B)analysis of water bubbles trapped in ice
C)the ratio of oxygen 18 to sulfur 34 in the shells of marine organisms
D)study of documents describing floods, droughts, and crop yields

Answer 3

D

Question 4

Which of the following describes the climate of the Medieval Climatic Optimum?

A)It was a relatively warm period.
B)It was a relatively wet period.
C)It was a relatively cold period.
D)It was a relatively dry period.

Question 5

Which of the following represents the duration of the warming trend that began in the 1970s?

A)It ended during the late 1990s.
B)It ended during the mid 1980s.
C)It ended to the early 1990s.
D)It extended into the 21st century.

Question 6

Greenhouse gases increase temperatures by absorbing and releasing which of the following?

A)shortwave radiation emitted from Earth
B)shortwave radiation emitted from the sun
C)longwave radiation emitted from Earth
D)longwave radiation emitted from the sun

Question 7

If the Earth was in a warming trend, which of the following processes would most likely act as a negative feedback mechanism?

A)decreasing the amount of cloud cover around the Earth
B)increasing the carbon dioxide content of the air
C)increasing the snow cover around the Earth
D)increasing the water vapour content of the air

Question 8

Which of the following functions do the general circulation models provide?

A)simulation of local climate
B)prediction of temperature changes
C)daily forecasts of severe weather
D)predictions of hurricane intensity

Question 9

Which of the following statements describes the overall effect of clouds?

A)They have a net warming effect on climate.
B)They have a net cooling effect on climate.
C)They are the most important feature in determining climate.
D)They have no net effect on climate.

Question 10

Which of the following time periods does the Maunder minimum refer to?

A)when the Earth was closer to the sun than it is now
B)when the tilt of the Earth's axis was less than it is now
C)when the Earth was in the middle of an ice age
D)when there were fewer sunspots on the sun than now

Question 11

Which of the following factors relates to explanations of climatic changes as provided by the theory of plate tectonics?

A)the position of the oceans
B)the amount of CO2 and H2O removed from the atmosphere
C)the paths taken by ocean winds
D)mountain building

Question 12

Referring to the much studied temperature record of the past 140 years, significantly more observations were made of which of the following temperature records?

A)ocean bottom waters temperatures
B)air temperatures over the oceans
C)air temperatures
D)freshwater lakes temperatures

Question 13

Which of the following changes to the sun's total energy output will likely occur as the number of sunspots increases?

A)slight decrease
B)no change
C)alternately increase and decrease above average values
D)slight increase

Question 14

Which of the following represents the most recent time that thick sheets of ice advanced over North America as far south as New York?

A)18,000 to 22,000 years ago
B)45,000 to 50,000 years ago
C)250,000 to 500,000 years ago
D)2 million years ago, at the beginning of the Pleistocene epoch

Question 15

Which of the following atmospheric aerosols can be found in the stratosphere?

A)sulphate aerosols
B)smoky soot
C)soil dust
D)automobile emissions

Question 16

Which of the following controls the ocean's conveyor belt circulation?

A)gradients in algae concentration
B)gradients in particulates concentration
C)gradients in water salinity
D)gradients in water turbidity

Question 17

Which of the following temperature changes will most likely coincide with an increase in atmospheric CO2 concentrations?

A)warming in the troposphere and warming in the upper atmosphere
B)warming in the troposphere and cooling in the upper atmosphere
C)cooling in the troposphere and cooling in the upper atmosphere
D)cooling in the troposphere and warming in the upper atmosphere

Question 18

Which of the following conditions most likely produces warming at the Earth's surface?

A)an increase in low-level global cloudiness
B)a decrease in energy output of the sun
C)an increase in high-level global cloud cover
D)an increase in sulphur-rich particles in the stratosphere

Question 19

Which of the following statements represents the global climate throughout much of the Earth's history?

A)It was likely warmer than it is today.
B)It was likely about the same temperature as it is today.
C)It was likely colder than it is today.
D)It was likely more variable than it is today.

Question 20

Which of the following provides a basis for the much-studied temperature record of the past 140 years?

A)ice cores and fossil shells
B)air temperature over land and the oceans
C)air temperature over the oceans and fossil shells
D)air temperatures over land and tree rings

Question 21

Which of the following describes the most favourable northern hemisphere climate for the formation of continental glaciers over vast areas of North America?

A)summers are warm and winters are extremely cold
B)summers are cool and winters are extremely cold
C)summers are cool and winters are mild
D)summers are warm and winters are mild

Question 22

Suppose the average snowfall over an area of Nunavut is 100 cm per year. How many years will it take for the snow to reach a depth of 1000 metres? (Assume there is no melting in summer and no compaction)

A)1000 years
B)10,000 years
C)100,000 years
D)10 years

Question 23

When did the current warming trend observed on Earth start?

A)about 500 years ago
B)about 100 years ago
C)about 1,000 years ago
D)about 10,000 years ago

Question 24

Which of the following could be responsible for the most recent warming trend in the northern hemisphere?

A)increase in levels of CO2
B)increase in volcanic eruptions
C)light-coloured particles in the stratosphere
D)decrease in energy emitted by the sun

Question 25

Which of the following conditions occurred during the Little Ice Age?

A)Alpine glaciers grew in size and advanced.
B)The climatic optimum occurred.
C)The Bering land bridge formed.
D)Continental glaciers covered large portions of North America.

Question 26

The greatest surface warming is projected for which of the following regions during the next 100 years?

A)polar regions
B)tropics
C)middle latitudes
D)equator

Question 27

Climatic models predict that the concentration of a certain gas must increase in the atmosphere for CO2 to produce a global warming of between 2°C and 5°C. According to this prediction, which of the following gases must increase?

A)chlorofluorocarbons (CFCs)
B)water vapour (H2O)
C)sulfur dioxide (SO2)
D)ozone (O3)

Question 28

Compared to a period when the Earth's orbital tilt has an intermediate value, which of the following statements probably refers to a period when the Earth's orbital tilt is at a minimum?

A)There would be a greater likelihood of glaciers at high latitudes.
B)There would be more seasonal variations at middle latitudes.
C)There would be more seasonal variations between summer and winter.
D)Less snow would probably fall during the winter in the polar regions.

Question 29

Although sea level glaciers probably never before existed near sea level at the equator, which of the following theories explains how glacial material can be observed there today?

A)theory of plate tectonics
B)Maunder theory
C)Milankovitch theory
D)volcanic dust theory

Question 30

Which of the following conditions likely caused the "year without a summer" in 1816?

A)a dust cloud produced when a meteorite collided with the Earth
B)deforestation
C)particulate matter and gases from volcanoes
D)soot from coal fires

Question 31

Which of the following patterns refers to a quasi-biennial oscillation?

A)reversal of stratospheric winds above the tropics
B)2 million-year cycle of ice advances and retreats
C)cycle of increase and decrease in carbon dioxide concentrations
D)22-year cycle of sunspots

Question 32

Which of the following is an accurate statement about the Younger Dryas?

A)It occurred approximately 100,000 years ago.
B)It lasted approximately 20 years.
C)Temperatures were relatively warm in the northern hemisphere.
D)It was likely caused by melting ice sheets.

Question 33

Which of the following tends to occur at the surface when an ash veil from large volcanic eruptions enters the stratosphere?

A)temperatures increase
B)precipitation increases
C)temperatures decrease
D)precipitation decreases

Question 34

Which of the following substances is particularly abundant in volcanoes that have the most impact on global climate?

A)carbon dioxide
B)nitrogen
C)sulphur
D)water vapour

Question 35

Which of the following describes the concentration of CO2 in the lower atmosphere?

A)It is 30 percent higher than it was 300 years ago.
B)It has stabilized.
C)It is not related to the amount of forest cover on Earth.
D)The present average measurement is 150 ppm.

Question 36

Which of the following statements describes the mid-Holocene climatic optimum?

A)Continental ice sheets began to melt.
B)Alpine glaciers began to advance down river valleys.
C)Average temperatures were colder than at present.
D)The climate favoured the development of certain plants.

Question 37

Which of the following conditions will likely occur if global temperatures continue to rise?

A)The oceans will increase the amount of CO2 in the atmosphere.
B)The oceans will have no effect on atmospheric CO2 concentrations.
C)The oceans will reduce the amount of CO2 in the atmosphere.
D)The oceans could increase or reduce the amount of CO2 in the atmosphere.

Question 38

Which of the following describes the Maunder Minimum?

A)It occurred during the Little Ice Age.
B)There were many sunspots.
C)It caused a significant change in the eccentricity of Earth's orbit.
D)It has been studied by analysis of ice cores in Antarctica.

Question 39

Suppose a high concentration of oxygen 16 was found in the ice caves of Antarctica and Greenland. Which of the following conditions likely occurred at the time the ice was formed?

A)cold air temperatures
B)intense ultraviolet radiation
C)the caves were under the ocean
D)mild winters

Question 40

Which of the following describes the apparent change in the average global temperatures over the past 100 years or so?

A)They have increased slightly.
B)They have fluctuated widely but shown no overall change.
C)They have decreased slightly.
D)They have remained constant.

Question 41

In what ways might climate change benefit the planet?

Question 42

Discuss the significance of a predicted increase in global temperatures of 3°C, as opposed to a predicted increase of 1°C.

Question 43

In association with other natural factors, the Milankovitch cycles explain the advance and retreat of glaciers according to which of the following time periods?

A)hundreds of millions of years
B)several million years
C)ten thousand years to one hundred thousand years
D)hundreds of thousands of years

Question 44

In which of the following periods did the Viking colony in Greenland perish?

A)climatic optimum
B)Pleistocene epoch
C)Mt.Pinatubo explosion
D)Little Ice Age

Question 45

What percentage of the Earth's surface does ice presently cover?

A)less than 1%
B)about 5%%
C)about 66%
D)about 10%

Question 46

What are some of the possible consequences of climate change?

Question 47

Ice cores provide a record of which of the following?

A)past temperatures
B)past wind patterns
C)past biodiversity
D)past precipitation

Question 48

In a warmer world, which of the following changes will likely happen to the growing season at higher latitudes?

A)The growing season will remain unchanged.
B)The growing season will be shorter at first, but then will be longer.
C)The growing season will be shorter.
D)The growing season will be longer.

Question 49

Which of the following accurately compares CO2 levels during cold glacial periods and warm interglacial periods?

A)CO2 levels of cold glacial periods were about the same as warm interglacial periods.
B)CO2 levels of cold glacial periods were more variable than warm interglacial periods.
C)CO2 levels of cold glacial periods were higher than warm interglacial periods.
D)CO2 levels of cold glacial periods were lower than warm interglacial periods.

Question 50

Discuss the changes that occur in the Earth's orbit and the orientation of the Earth in its orbit. Over what time scales do these different changes occur?

Question 51

What is meant by the term positive feedback? What role could positive feedback play in the atmospheric greenhouse effect? Would this enhance or reduce global warming? What is an example of a "negative feedback" mechanism?

Question 52

Asia and the North American continent have been connected by a land bridge at various times during the past. When was the Bering land bridge most recently exposed? Did this coincide with a warm or cool climatic period?

Question 53

Which of the following defines a positive feedback mechanism?

A)an action that weakens or opposes an initial change
B)an action that reinforces an initial change
C)an action that causes a positive change
D)an action that causes a negative change

Question 54

Carbon dioxide concentrations in the atmosphere have been increasing steadily since the beginning of the industrial revolution and may double by the middle of the next century. Why is this of concern?

Question 55

Which of the following refers to the precession of the equinox?

A)changes in the seasons, especially from winter to summer
B)changes in the tilt of the Earth's axis as it orbits the sun
C)the wobble of the Earth on its axis
D)changes in the shape of the Earth's orbit as the Earth revolves around the sun

Question 56

In addition to carbon dioxide, what other gases may contribute to the problem of global warming? Why might global warming lead to an increase in global cloudiness? What possible effects would an increase in cloudiness have on global warming?

Question 57

Which of the following reasons for climatic change is proposed by the Milankovitch theory?

A)volcanic eruptions
B)changing levels of CO2 in the Earth's atmosphere
C)particles suspended in the Earth's atmosphere
D)variations in the Earth's orbit as it travels through space

Question 58

Everything else being equal, which of the following will most likely result from a gradual increase in global CO2?

A)a decrease in evaporation from the Earth's oceans
B)no change in global climate
C)an increase in surface air temperature
D)a marked decrease in plant growth

Question 59

If the Earth was in a cooling trend, which of the following processes would most likely act as a positive feedback mechanism?

A)increasing the snow cover around the Earth
B)increasing the water vapour content of the air
C)decreasing the amount of cloud cover around the Earth
D)increasing the carbon dioxide content of the air

Question 60

Which of the following statements applies to the biogeophysical feedback mechanism that occurs in the Sahel?

A)Reduced cloud cover relates to an increase in both surface temperatures and rainfall.
B)Reduced vegetation relates to a lower surface albedo and an increase in rainfall.
C)Reduced vegetation relates to a decrease in both surface temperatures and rainfall.
D)Increased vegetation relates to an increase in surface temperatures and a decrease in rainfall.

Question 61

Describe some of the techniques used to infer past climates. About how far into the past are these different methods able to reconstruct past climatic conditions?

Question 62

When did the Little Ice Age occur? Have there been any suggestions of a possible cause of the Little Ice Age?

Question 63

Where is the Sahel located? Is this a region of scarce, variable, or abundant rainfall? Describe the biogeophysical feedback mechanism whereby a reduction in surface vegetation might cause a reduction in precipitation amounts.

Question 64

Assume that you have 100 years of continuous temperature records from your local weather service office. Discuss some of the difficulties you might have trying to determine whether average temperatures have increased during this period.

Question 65

What combination of the Earth's orbital eccentricity and the precession and obliquity of the Earth's axis produces the hottest summer temperatures in the northern hemisphere?

Question 66

Does deforestation act to increase or decrease atmospheric carbon dioxide concentrations?

Question 67

Briefly describe the climatic variations that have occurred since the beginning of the Pleistocene epoch to the present day.

Question 68

Discuss some of the challenges that climatologists face when attempting to reconstruct the climate of the past.

Question 69

Explain how analysis of glacial and polar ice cores provides important clues about past climate.