Deck 15: The Earths Changing Climate

Question 1

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

Answer 1

B

Question 2

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

Answer 2

A

Question 3

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

Answer 3

B

Question 4

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 5

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 6

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 7

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 8

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 9

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 10

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 11

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

Question 12

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 13

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 14

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)all of the above
E)only a and b

Question 15

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 16

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 17

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 18

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 19

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 20

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 21

The Milankovitch cycles in association with other natural factors explain how glaciers may advance and retreat over periods of hundreds of millions of years.

Question 22

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? Can you think of any "negative feedback" mechanisms?

Question 23

During the Little Ice Age,the climatic optimum occurred.

Question 24

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

Question 25

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 26

During the Pleistocene epoch,continental glaciers alternately advanced and retreated over large portions of North America and Europe.

Question 27

The most recent warming trend experienced over the Northern Hemisphere could be the result of increasing volcanic eruptions.

Question 28

The much-studied temperature record of the past 140 years is derived from land-based observations only.

Question 29

Presently glaciers cover less than 1% of the earth's surface.

Question 30

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

Question 31

During the climatic optimum,alpine glaciers began to advance down river valleys.

Question 32

The earth has been in a warming trend for

A)more than 100 years
B)more than 500 years
C)more than 1000 years

Question 33

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 34

The Milankovitch Theory proposes that climatic changes are due to particles suspended in the earth's atmosphere.

Question 35

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

A)shorter
B)longer

Question 36

Precession of the equinox refers to the wobble of the earth on its axis.

Question 37

Lowering of sea levels is not one of the possible consequences of global warming predicted by climate models.

Question 38

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 colder the climate at that time.

Question 39

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 40

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

Question 41

What are some of the possible consequences of global warming?

Question 42

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 43

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 44

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

Question 45

In what ways might global warming benefit the planet?

Question 46

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 47

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

Question 48

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 49

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

Question 50

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?