Deck 13: Global Climate

Question 1

Throughout much of the earth's history, the global climate was probably ____.

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

Answer 1

A

Question 2

During the Pleistocene epoch, ____.

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

Answer 2

C

Question 3

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

Answer 3

C

Question 4

During the climatic optimum, ____.

A) the climate favored the development of certain plants
B) average temperatures were colder than at present
C) continental ice sheets began to melt
D) alpine glaciers began to advance down river valleys

Question 5

The CLIMAP project was able to reconstruct the earth's ocean surface temperature in the past by examining ____.

A) deep ocean water
B) rock layers on land
C) thousands of feet of sediment at the bottom of the ocean
D) soils deposited over the North American continent

Question 6

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 7

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 8

The "year without a summer" occurred in ____.

A) 1950
B) 1816
C) 1735
D) 1681

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 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 11

The Viking colony in Greenland perished during the ____.

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

Question 12

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 13

During the Little Ice Age, ____.

A) the climatic optimum occurred
B) sea level lowered by about 280 ft
C) alpine glaciers grew in size and advanced
D) continental glaciers covered large portions of North America

Question 14

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 15

The Sahel ____.

A) is mostly a sand-covered desert
B) is a region of variable rainfall
C) always had a food surplus
D) is located in Saudi Arabia

Question 16

The most recent North American glaciers reached their maximum thickness and extent ____.

A) in 1,700 A.D.
B) in 2,000 B.C.
C) about 18,000 to 22,000 years ago
D) about two million years ago, at the beginning of the Pleistocene epoch

Question 17

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 18

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 19

Presently, ice sheets and glaciers cover ____ of the earth's surface.

A) about 10 percent
B) less than one percent
C) about one-quarter
D) about two-thirds

Question 20

The "year without a summer" 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

Question 21

Plate tectonics "explains" certain climatic changes by showing that these changes may be related to ____.

A) mountain building
B) the position of the continents
C) the paths taken by ocean currents
D) all of these

Question 22

Climate models predict that if average global temperatures rise, both global precipitation and drought will ____.

A) increase
B) decrease
C) remain the same
D) vary from year to year

Question 23

During a period when the earth's orbital tilt is at a minimum, what would most likely to occur?

A) There should be less seasonal variation between summer and winter.
B) There would be more snowfall during the winter in polar regions.
C) There would less of a likelihood of glaciers at high latitudes.
D) There would be less seasonal variations at middle latitudes.

Question 24

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 25

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 26

Ozone is a greenhouse gas that ____ role in the enhancement of the greenhouse effect.

A) plays a minor
B) plays a major
C) plays the most important
D) has no

Question 27

Which decade was the warmest on record?

A) 1930-1939
B) 1960-1969
C) 1990-1999
D) 2000-2009

Question 28

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 to one hundred thousand years

Question 29

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 30

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 31

Additional clouds in a warmer world ____.

A) would have a net warming effect
B) would have a net cooling effect
C) would have no warming or cooling effect
D) could enhance or reduce warming

Question 32

The most recent warming trend experienced over the Northern Hemisphere could be the result of ____.

A) light colored particles in the stratosphere
B) increasing levels of greenhouse gases
C) a decrease in the energy emitted by the sun
D) an observed decrease in snow cover

Question 33

Volcanic eruptions that have the greatest impact on global climate appear to be those rich in ____.

A) nitrogen
B) water vapor
C) carbon dioxide
D) sulfur

Question 34

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 35

The Milankovitch theory suggests that climates changes on the earth could be caused by changes in ____.

A) the shape of the earth's orbit around the sun
B) the direction of tilt of the earth's axis
C) the amount of tilt of the earth's axis
D) all of these

Question 36

Warming at the earth's surface will most likely occur when there is an increase in the amount of ____.

A) low-level global cloud cover
B) sulfur-rich particles in the stratosphere
C) global snow cover
D) high-level global cloud cover

Question 37

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 38

The Milankovitch Theory proposes that climatic changes are due to ____.

A) variations in the earth's orbit as it travels around the sun
B) volcanic eruptions
C) changing levels of CO₂ in the earth's atmosphere
D) particles suspended in the earth's atmosphere

Question 39

The Maunder Minimum refers to a time when ____.

A) the tilt of the earth's axis was less than it is now
B) there were fewer sunspots
C) the earth was closer to the sun than it is now
D) few snowstorms occurred over the United States

Question 40

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 41

Instructions: Choose one answer from each pair of selections. The nuclear winter scenario envisions an upper level layer of strongly REFLECTING | ABSORBING soot particles which would cause the ground to cool by reducing the amount of sunlight able to reach the ground.

Question 42

Some scientists believe the earth is in a comparatively warm part of an ice age.

Question 43

Instructions: Choose one answer from each pair of selections. Sulfate aerosols are good REFLECTORS | ABSORBERS of sunlight and their effect on climate has been studied extensively in recent years.

Question 44

How many degrees did the globe warm in the 20th century? Why is this amount considered significant?

Question 45

Warm ocean water cannot contain as much dissolved carbon dioxide as cool ocean water.

Question 46

Instructions: Choose one answer from each pair of selections. When the conveyor belt ocean circulation stops, winters in Europe are much WARMER | COLDER than normal.

Question 47

Instructions: Choose one answer from each pair of selections. Did the Little Ice Age occur during a period of HIGH or LOW sunspot activity?

Question 48

Climate models predict that oceans will warm more rapidly than landmasses in the northern high latitudes will warm under future climate conditions.

Question 49

Instructions: Choose one answer from each pair of selections. Volcanic eruptions rich in sulfur tend to WARM | COOL the surface?

Question 50

Instructions: Choose one answer from each pair of selections. Global mean surface temperatures appear to have increased slightly since the early 1900s. The greatest increase has occurred over the CONTINENTS | OCEANS in winter and spring.

Question 51

Define the snow-albedo positive feedback mechanism.

Question 52

The average warming experienced over the globe since the early 1900s has not been uniform. Where have the greatest and least amounts of warming occurred?

Question 53

Instructions: Choose one answer from each pair of selections. Human activities add aerosols to the atmosphere; the overall effect of these particles on climate appears to be a net COOLING | WARMING of surface temperatures.

Question 54

Instructions: Choose one answer from each pair of selections. The more elliptical the earth's orbit is, the GREATER | SMALLER the variation in solar energy received by the earth between its closest and farthest distance from the sun.

Question 55

Recent evidence suggests that the variations in the earth's orbit around the sun proposed by Milankovitch actually have very little effect on the earth's climate.

Question 56

Briefly explain radiative equilibrium.

Question 57

What is dendrochronology?

Question 58

Instructions: Choose one answer from each pair of selections. Analysis of the oxygen-isotope ratio in ancient ice cores tells us the COLDER | WARMER the air was, the richer the concentration of oxygen 16 in the core.

Question 59

The combined effect of trace greenhouse gases (such as methane (CH₄), nitrous oxide (N₂O), and CFCs) in enhancing the greenhouse effect is about equal to carbon dioxide.

Question 60

Instructions: Choose one answer from each pair of selections. Would you expect the chain reaction known as a runaway greenhouse effect to result from an unchecked POSITIVE or NEGATIVE feedback process?

Question 61

Explain what could have caused the large fluctuations in the climate in only a matter of years around Greenland during the last glacial period.

Question 62

How can the oxygen-isotope ratio of the remains of calcium carbonate shells of organisms found in ocean sediment provide information about past sequences of glacier advances and retreats?

Question 63

Explain positive and negative climate feedback mechanisms and provide an example for each.

Question 64

How can deforestation contribute to global warming?

Question 65

Discuss why it is so difficult to prove that the earth's present warming trend is due entirely to increasing concentrations of greenhouse gases?