Deck 9: The Cryosphere

Question 1

If the higher latitudes of Earth suddenly warmed up by 5 to 10 degrees Centigrade, how would the salinity of the water in the high latitudes change? How would global circulation of the ocean almost immediately be affected?

Answer 1

If the higher latitudes of Earth suddenly warmed up by 5 to 10 degrees Centigrade, the salinity of the water in the high latitudes would likely decrease. This is because the warmer temperatures would cause increased melting of polar ice and glaciers, leading to a greater input of freshwater into the ocean.

As a result, the decreased salinity in the high latitudes would have immediate effects on the global circulation of the ocean. The lower salinity water would be less dense and therefore less likely to sink, disrupting the normal patterns of deep water formation and the global thermohaline circulation. This could lead to changes in ocean currents and temperature distribution, impacting climate patterns and weather systems around the world.

Additionally, the changes in salinity and temperature could also have cascading effects on marine ecosystems, impacting the distribution and abundance of marine life in the affected regions. Overall, the sudden warming of the higher latitudes would have significant and complex impacts on the global ocean circulation and the broader Earth system.

Question 2

If only sea ice were to melt during global warming (and not land ice), how significantly would global sea level change? Explain why this is the case.

Answer 2

If only sea ice were to melt during global warming (and not land ice), the global sea level would not change significantly. This is because sea ice is already floating on the water, and its melting does not contribute to a rise in sea level.

Sea ice forms when ocean water freezes, and when it melts, it simply returns to the ocean as liquid water. Since the ice is already displacing its own weight in the water, its melting does not add extra volume to the ocean. Therefore, the melting of sea ice alone would not lead to a significant change in global sea level.

On the other hand, if land ice were to melt, such as ice sheets and glaciers, it would significantly contribute to a rise in global sea level. This is because land ice is not already in the ocean, and when it melts, the resulting water flows into the ocean, increasing its volume.

In conclusion, the melting of only sea ice during global warming would not lead to a significant change in global sea level, as it is already floating in the ocean and does not add extra volume when it melts.

Question 3

The part of the Earth's surface that remains perennially frozen constitutes the __________ .

Answer 3

cryosphere

Question 4

The altitude of the __________ and its horizontal position on the landscape typically change from year to year depending on the weather.

Question 5

A __________ is a persistent body of ice consisting largely of recrystallized snow.

Question 6

Huge continent-sized __________ sheets overwhelm nearly all the land surface within their margins.

Question 7

As a result of __________ over the course of a year or more, accumulated snow gradually becomes denser and denser until it is not longer permeable to air.

Question 8

The crystal structure of snow has a __________ symmetry, which means that it typically forms as a six-sided crystal.

Question 9

Ice throughout a warm glacier, more commonly called a __________ glacier, can coexist in equilibrium with water.

Question 10

The front, or __________ of a glacier is likely to advance as the glacier grows.

Question 11

When an accumulating mass of snow and ice on a mountainside reaches a critical thickness, the mass begins to deform and flow downslope under the pull of __________ .

Question 12

In 1912, the S.S. Titanic sank after striking an __________ .

Question 13

Glacially carved __________ deeply indent the mountainous, west-facing coasts of Norway, Alaska, British Columbia, Chile, and New Zealand.

Question 14

Ridge-like accumulations of sediment called __________ form as sediment is bulldozed by a glacier advancing across the land.

Question 15

The most characteristic feature of periglacial regions is perennially frozen ground, also known as __________ .

Question 16

Approximately two-thirds of the area of Earth's persistent ice cover floats as a thin veneer of __________ ice on polar oceans.

Question 17

When sea ice melts, the __________ of the water is decreased as fresh water is added to the ocean surface.

Question 18

Ice has a high __________ which means that an ice-covered surface reflects a large amount of incoming solar radiation.

Question 19

The global circulation of the world ocean is directly influenced by the formation and melting of __________ .

Question 20

Each year, about __________ percent of the Arctic Sea ice moves south into the Greenland Sea, where it eventually breaks up and melts away.

Question 21

The cryosphere is the part of Earth's surface that is perennially frozen.

Question 22

The crystal structure of snow is closed and dense.

Question 23

In the northern hemisphere, almost 60% of the land area is covered by seasonal snow and frozen ground during the winter.

Question 24

The huge continental ice sheets of Greenland and Antarctica contain about 95% of existing glacial ice.

Question 25

Glaciers generally develop below sea level in the polar regions.

Question 26

In the temperature ("warm") glaciers of low and middle latitudes, ice can coexist with water.

Question 27

When a glacier gains more mass than it loses over a period of years, its volume increases and the terminus advances.

Question 28

Glacial ice flows upslope under the influence of gravity.

Question 29

Icebergs float with most of their volume above sea level.

Question 30

There is evidence of glacial-interglacial cycles as long as 2.4 billion years ago.

Question 31

Very little of Earth's land area has been shaped by glaciers.

Question 32

A valley that has been shaped by glaciers has a distinctive U-shaped cross section and a floor that lies below its tributary valleys.

Question 33

Till is a glacial sediment that occurs in unsorted and unstratified deposits.

Question 34

The largest areas of permafrost occur in eastern South America and the Tibetan Plateau.

Question 35

Solifuction is a common mass-wasting process in which waterlogged regolith in a thawed, active layer moves slowly downslope.

Question 36

Glacial ice contains abundant physical, chemical, and biological evidence of past changes in local and global environmental conditions.

Question 37

Approximately 75% of Earth's permanent ice cover is sea ice.

Question 38

The North Pole is located in the Antarctic continent, covered by a vast, thick ice sheet.

Question 39

Sea ice is in constant motion, driven by winds and currents.

Question 40

Ice has a low albedo, which makes the ice-covered polar regions far warmer than if the same areas were covered with water or land.

Question 41

Features such as cirques are associated with what type of glaciation?

A) Fjords.
B) Valley glaciation.
C) Mountain glaciation.
D) Lowland glaciation.

Question 42

If the rate of accumulation is the rate of ablation, a glacier will advance from its source area.

A) Equal to.
B) Less than.
C) Greater than.
D) Much less than.

Question 43

Glaciers cover about how much of the land surface?

A) 5%
B) 20%
C) 30%
D) 10%

Question 44

Which of the following is not a component of the cryosphere?

A) Seawater.
B) Seasonal snow cover.
C) Sea ice.
D) Ice shelves.
E) Permafrost.

Question 45

In polar regions, the amount of annual snowfall is generally very low. Why is this?

A) The air is too warm to hold much moisture.
B) The air is too cold to hold much moisture.
C) The pressure is too high to hold much moisture.
D) The pressure is too low to hold much moisture.

Question 46

Where do Earth's large ice sheets now exist?

A) Greenland and Asia.
B) Greenland and Antarctica.
C) Antarctica and Asia.
D) Canada and Greenland.

Question 47

If you were to analyze a deep ice core, what would expect to be the relative sizes of the ice crystals that make up the core? Start from the top layer and work your way down to the bottom layer.

A) Large, small, medium.
B) Large, medium, small.
C) Medium, small, large.
D) Small, medium, large.

Question 48

Where are most glaciers found?

A) Mid-latitude cold zones.
B) Lower latitudes on high mountains.
C) The high-latitude polar regions.
D) None of these.

Question 49

What is the typical crystal structure of snow?

A) Tetrahedral.
B) Hexagonal.
C) Octagonal.
D) Pentagonal.

Question 50

Where would one find the equilibrium line on a glacier?

A) The point where net mass loss is less than net mass gain.
B) The point where net mass loss is greater than net mass gain.
C) The point where net mass loss equals net mass gain.

Question 51

Where would the surface velocity across a valley glacier be the fastest?

A) Uppermost ice in the central part of the glacier.
B) Ice at the sides of the glacier.
C) Ice at the bottom of the glacier.

Question 52

What is frontal calving?

A) Breaking off of icebergs from the back of a glacier that terminates in shallow water.
B) Breaking off of icebergs from the front of a glacier that terminates in shallow water.
C) Breaking off of icebergs from the back of a glacier that terminates in deep water.
D) Breaking off of icebergs from the front of a glacier that terminates in deep water.

Question 53

What percentage of an iceberg will be below the sea?

A) 90%
B) 10%
C) 50%
D) 75%

Question 54

What is a moraine?

A) A deep crevice filled with sediment.
B) U-shaped valley, filled with sediment.
C) Ridge-like accumulation of sediment.
D) None of these.

Question 55

When did the most recent ice age begin?

A) About 10,000 years ago.
B) About 100,000 years ago.
C) About 50,000 years ago.
D) About 70,000 years ago.

Question 56

What is the most characteristic feature of periglacial regions?

A) Fjords.
B) Continental ice sheets.
C) Large glaciers.
D) Permafrost.

Question 57

What is the highest point called at which a glacier's winter snow cover is lost during a given season?

A) Tree-line.
B) Snowline.
C) Frost-line.
D) Equilibrium line.

Question 58

If the amount of ice that a glacier loses is greater than the amount of snow it gains, it will

A) Retreat.
B) Advance.
C) Stay motionless.

Question 59

How are icebergs formed?

A) By freezing seawater.
B) By pieces of glacial ice breaking off the glacier.
C) By pieces of intercontinental ice migrating toward the ocean.
D) By river ice from mountain zones flowing to the sea.

Question 60

As you go from lower to higher latitudes, the altitude of the snow line should

A) Increase.
B) Decrease.
C) Stay the same.
D) Need more information.

Question 61

The zone of accumulation is generally characterized by

A) Striations.
B) Ablation.
C) Thick sediment.
D) The thickest development of glacial ice.

Question 62

What is the major feature of a valley formed by a glacier versus a valley formed by a stream?

A) Deep moraines.
B) W-Shape.
C) U-Shape.
D) V-Shape.

Question 63

Where does a medial moraine develop?

A) In the middle of two coalesced glaciers.
B) On the side of a glacier.
C) At the top of a glacier.
D) Near the bottom of a glacier.

Question 64

What is the sudden movement of a glacier due to a sudden addition of snow on ice called?

A) Calving.
B) A surge.
C) Slipping.
D) Frosting.

Question 65

When did the most recent ice age occur?

A) Mesozoic.
B) Precambrian.
C) Cambrian.
D) Pleistocene.

Question 66

During the most recent ice age, about what percentage of glaciers covered the Earth's land area?

A) 20%
B) 30%
C) 50%
D) 70%

Question 67

What will be the result of sea level rising, causing the ocean to fill a glacially carved valley?

A) A surge.
B) A moraine.
C) A fjord.
D) A horn.

Question 68

Which of the following terms refers to glacial melting below the snow line?

A) Ablation.
B) Calving.
C) Surging.
D) Plucking.

Question 69

Where do crevasses form in glaciers?

A) Where a glacier is accumulating.
B) Where a glacier is melting.
C) Where a glacier is subjected to tension.
D) Any of these.

Question 70

When will Arctic sea ice typically reach it minimum?

A) June.
B) September.
C) August.
D) December.

Question 71

What are large boulders deposited by glaciers called?

A) Drifts.
B) Drumlins.
C) Moraines.
D) Tills.

Question 72

What is the outermost limit of a glacier's advance called?

A) Lateral moraine.
B) Medial moraine.
C) Ground moraine.
D) Terminal moraine.

Question 73

Which of the following glacial features cannot be used to determine the direction of ice movement?

A) Loess.
B) Drumlins.
C) Striation.
D) Boulder trains.

Question 74

How deep do crevasses in glaciers extend down to?

A) About 1000 meters.
B) Zone of plastic flow.
C) Slightly through the continent.
D) The very bottom of the glacier.