Deck 16: Earths Changing Climate

Question 1

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

Answer 1

E

Question 2

Presently glaciers cover ____ of the earth's surface.

A) about 10 percent
B) less than 1 percent
C) approximately two thirds
D) none

Answer 2

A

Question 3

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.

Answer 3

B

Question 4

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.

Question 5

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

Question 6

If the average snowfall over an area of north central Canada is 100 cm per year,how long would it take for the snow to reach a depth of 1,000 meters? (Assume that there is no melting in summer and no compaction. )

A) 10 years
B) 1,000 years
C) 10,000 years
D) 100,000 years
E) 10,000,000 years

Question 7

Ice cores record both the record of past temperatures and the causes of climate change.

Question 8

A positive feedback mechanism

A) acts to reinforce an initial change.
B) acts to weaken or oppose an initial change.
C) will cause a positive change.
D) will cause a negative change.

Question 9

If the earth were in a warming trend,which of the processes below would most likely act as a negative feedback mechanism?

A) increasing the water vapor content of the air
B) increasing the snow cover around the earth
C) decreasing the amount of cloud cover around the globe
D) increasing the carbon dioxide content of the air

Question 10

Indications of past climates in tree rings are determined by examination of the:

A) thickness of growth rings.
B) density of growth rings.
C) presence of frost rings.
D) both thickness and density of growth rings.
E) all of the above

Question 11

The Viking colony in Greenland perished during

A) the Pleistocene epoch.
B) the climatic optimum.
C) the Little Ice Age.
D) the explosion of Mount Pinatubo.

Question 12

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

Question 13

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.

Question 14

During the Little Ice Age,

A) the climatic optimum occurred.
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 feet.

Question 15

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

Question 16

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.

Question 17

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.

Question 18

If the earth were in a cooling trend,which process below would most likely act as a positive feedback mechanism?

A) increasing the snow cover around the earth
B) increasing the water vapor content of the air
C) decreasing the amount of cloud cover around the globe
D) increasing the carbon dioxide content of the air

Question 19

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.

Question 20

Which theory explains how glacial material can be observed today near sea level at the equator,even though sea level glaciers probably never existed there?

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

Question 21

Volcanoes that have the most impact on global climate seem to be those rich in

A) nitrogen.
B) water vapor.
C) carbon dioxide.
D) sulfur.
E) oxygen.

Question 22

The much-studied temperature record of the past 140 years is derived from

A) land-based observations only.
B) oceanic observations only.
C) both land-based and oceanic observations.

Question 23

For CO₂ to produce a global warming of between 2C and 5C,climatic models predict that the concentration of this gas must also increase in the atmosphere:

A) chlorofluorocarbons (CFCs)
B) nitrous oxide (N₂O)
C) water vapor (H₂O)
D) ozone (O₃)

Question 24

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

Question 25

An increase in atmospheric CO₂ concentrations will most likely lead to ____ in the troposphere and ____ in the upper atmosphere.

A) warming,warming
B) cooling,warming
C) warming,cooling
D) cooling,cooling

Question 26

Everything else being equal,a gradual increase in global CO₂ would most likely bring about

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

Question 27

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.

Question 28

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.

Question 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

Question 30

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.

Question 31

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

Question 32

A biogeophysical feedback mechanism in the Sahel relates

A) reduced cloud cover to increasing surface temperatures and an increase in rainfall.
B) reduced vegetation to a decrease in surface temperatures and a reduction in rainfall.
C) an increase in vegetation to an increase in surface temperatures and a reduction in rainfall.
D) a decrease in vegetation to a lowering of surface albedo and an increase in rainfall.

Question 33

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.

Question 34

Which below is not one of the possible consequences of global warming predicted by climate models?

A) accumulations of additional snow in Antarctica
B) a reduction in average precipitation over certain areas
C) lowering of sea levels
D) a cooling of the upper atmosphere
E) a drop in the rate of ozone destruction in the stratosphere

Question 35

The Maunder Minimum refers to a time when

A) the earth was in the middle of an ice age.
B) the tilt of the earth's axis was less than it is now.
C) the earth was closer to the sun than it is now.
D) few snowstorms occurred over the United States.
E) there were fewer sunspots on the sun.

Question 36

A significant percentage of the observations comprising the much-studied temperature record of the past 140 years were not air temperatures,but rather were temperatures of ocean surface waters.

Question 37

The formation of continental glaciers over vast areas of North America is most favorable when Northern Hemisphere summers are ____ and winters are ____.

A) cool,extremely cold
B) cool,mild
C) warm,extremely cold
D) warm,mild

Question 38

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.

Question 39

It appears that,as the number of sunspots increases,the sun's total energy output

A) increases slightly.
B) decreases slightly.
C) begins to alternately increase and decrease above average values.
D) does not change.

Question 40

The quasi-biennial oscillation is a pattern of

A) ice advances and retreats spanning 2 million years.
B) 22 year-long sunspot cycles.
C) reversing stratospheric winds above the tropics.
D) increases and decreases in carbon dioxide concentrations.
E) solar activity that takes about 2 years to complete its cycle.

Question 41

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

Question 42

The warming trend that began in the 1970s

A) extended to the 1990s.
B) ended during the mid-1980s.
C) has extended into the twenty-first century.

Question 43

All atmospheric aerosols are injected directly into the earth's atmosphere by either natural or human-made sources.

Question 44

Observations of ground-level and tropospheric temperature trends have always been found to be similar.

Question 45

Describe one positive and one negative feedback mechanism associated with human health or the human body.

Question 46

What are meant by the terms positive and negative feedback mechanisms? Give an example of a process that would be considered a positive feedback mechanism during a period of warming on the earth.Can you think of a negative feedback mechanism?

Question 47

General circulation models

A) simulate global climate.
B) predict temperature changes.
C) provide daily forecasts of severe weather.
D) all of these
E) simulate global climate and predict temperature changes.

Question 48

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

Question 49

In a warmer world,higher latitudes would have a ____ growing season.

A) shorter
B) longer

Question 50

During the next 100 years,the greatest surface warming is project to be in the

A) tropics.
B) mid-latitudes.
C) polar regions.

Question 51

The earth has been in a warming trend for

A) more than 100 years.
B) more than 500 years.
C) more than 1,000 years.

Question 52

Which of the following are external causes of climate change?

A) changes of the earth's surface
B) changes in atmospheric composition
C) changes in incoming solar radiation
D) all of these

Question 53

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 54

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 55

What combination of the earth's orbital eccentricity,and precession and obliquity of the earth's axis would produce hottest summer temperatures in the Northern Hemisphere?

Question 56

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

Question 57

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 58

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

Question 59

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

Question 60

In what ways might global warming benefit the planet?

Question 61

Describe the role of clouds in climate change.

Question 62

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

Question 63

What are some of the possible consequences of global warming?

Question 64

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 increased cloudiness have on global warming?

Question 65

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