Glaciers: Systems And Landscapes

Question 1

What is a system?

Answer 1

A system is a set of interconnected parts that work together. They have a series of stores or components and have flows between them.
Input —> store —> process —> store —> outputs
Systems can help us understand how energy and matter is transferred and stored.

Question 2

What are the 2 types of systems?

Answer 2

1. Open system- matter and energy can be transferred from the system across a boundary into the surrounding environment, e.g. drainage basin cycle
2. Closed system- transfers of energy both into and beyond the systems boundary- but not transfer matter, e.g. a planet.

Question 3

What are the systems in a glacier?

Answer 3

Glaciers have inputs, stores, transfers and outputs. Snow and ice are the most important inputs. They come from:
• direct snowfall
• Blown snow
• Avalanches from slopes surrounding all of the glaciers.
- Together these inputs are known as accumulation. These inputs are then transferred down-valley, under the influence of gravity, by glacial movement.
- Mass is lost from the system by either melting, evaporation or calving of ice blocks or icebergs. These outputs are known as ablation.
- Dynamic equilibrium- the ‘balanced state of a system’, e.g. where the inputs equal the outputs over time.

Question 4

What is a feedback loop?

Answer 4

The systems ‘self-regulate’ through feedback loops —> when one element of a system changes because of an outside influence. This upsets the equilibrium and changes the other components in the system. It can be both positive and negative:
- Positive feedback loops: accelerates or amplifies the effects of an action, e.g. the snowball effect
- Negative feedback loops: lessens or reverses the effects of the action, e.g. counter acts it.

Question 5

What’s an example of a positive feedback loop?

Answer 5

Climate change:
Temp rises —> permafrost melts —> CO2 released —> greenhouse effect —> (back to temps rising)

Question 6

What’s an example of a negative feedback loop?

Answer 6

Climate warming —> increased evaporation and cloud cover —> decreased incoming solar radiation —> cooling

Question 7

What is a glacial budget?

Answer 7

The GB considers the balance between the inputs and outputs. The net balance between the total accumulation and ablation during one year.
The glacier is is divided into 2 zones:
1. The accumulation zone - where there is a net gain of ice over the course of a year. Here inputs exceed the outputs.
2. The ablation zone, where there is a net loss of ice during the year. The losses exceed the gains.
The boundary where gains and losses are balanced is called the equilibrium line. Over a period of several years variations in global budgets result in line moving up or down glacier.
- During summer, ablation will be at its highest due to rapid ice melt
- During winter, high amounts of snowfall and limited melting result in accumulation being greater than ablation.

Question 8

What factors may cause glacial budgets to vary?

Answer 8

Altitude, Aspect, Short term temperature changes (e.g. seasons, heatwaves, cold snaps), long-term temperature change (e.g. glacials), precipitation.

Question 9

What is the polar environment and how are glaciers distributed?

Answer 9

(E.g. Antartica, Artic)
—> continuous areas of sea ice
- glaciers found at the edge or large sheets of ice
- vast ice sheets

Question 10

What is the glacial environment and how are glaciers distributed?

Answer 10

(E.g. Antartica, Greenland, etc)
- glaciers found at edge of large ice sheets
- areas of permanent ice

Question 11

What is the tundra environment and its features?

Answer 11

(E.g. Northern Alaska, Canada)
- has permafrost
- permanently frozen ground

Question 12

What is the Alpine environment and its features?

Answer 12

• areas of high relief
• small ice caps
• snow and ice remain throughout the year
• often in mountainous areas

Question 13

What are ice sheets?

Answer 13

Huge areas of ice (on land)

Question 14

what are ice caps?

Answer 14

Smaller coverings of ice

Question 15

How is latitude a factor that determines the climate?

Answer 15

the higher the latitude, the less solar radiation (energy/heat) the earth receives from the sun.

Question 16

How is altitude a factor that determines the climate?

Answer 16

less air particles that are heated up so therefore colder. Lower temperature due to lower air density.
(Altitude and latitude work together to create a broad range of glacier locations around the world)

Question 17

How is Aspect a factor that determines the climate?

Answer 17

is whether it is facing the right direction. A peak might be at correct latitude and altitude, but if it is not facing a certain way, it may be warmer/cooler. In the Northern hemisphere, the south side of a peak is warmer as it is facing the sun.

Question 18

How is relief a factor that determines the climate?

Answer 18

the height and shape of a land. Even if all other factors come together, the shape and slope (relief) of the land itself might prevent ice accumulation.

Question 19

How is distance from moisture source a factor that determines the climate?

Answer 19

glaciers and cold environments need precipitation in the form of snowfall for their development. ‘Continental areas’ are places with no moisture (sea, lakes, oceans, etc.)

Question 20

How is albedo a factor that determine the climate?

Answer 20

how reflective a surface is in areas of continuous snow cover, much of incoming solar radiation is reflected off the ice/snow surface.

Question 21

How is continentality a factor determining the climate?

Answer 21

ability of a piece of land to heat up interior of a continent and has a greater range of temperatures than a coastal part of the land.

Question 22

What is the interglacial period?

Answer 22

• a period of relative warmer global climate between two ice ages

Question 23

What was the glacial period?

Answer 23

a period of cold global temperatures leading to extensive ice cover. Often lasting upto 100,000 years.

Question 24

What is the Pleistocene glaciations period?

Answer 24

a geological time period that lasted from about 2.6 million years ago to 12,000 years ago.

Question 25

How were cold environments distributed in the past?

Answer 25

• spans the earths most recent period of repeated glaciations.
• Distributed mostly in the north and south of the earth.
• Pleistocene ice sheets covered about 25 to 30% of today’s land surface.
• Today’s ice sheets (Antarctic ice sheets and Greenland) cover only 10% of the land.
• 6-7 ice sheets existed in the Northern Hemisphere 21,000 years ago (the last glacial maximum)

Question 26

What are the historical periods of glacial Advance and Retreat?

Answer 26

• Glaciers have advanced and retreated in correlation with the world’s glacial and interglacial periods. Currently, the majority of glaciers are thought to be retreating due to increased temps.
• Glacial advance in the Alps was a very prevalent issue during the Little Ice Age. Heavy snowfall and avalanches were common and posed a risk to life.

Question 27

What are the physical characteristics for polar environments?

Answer 27

• Climate - doesn’t really get above 0 DC, as it has weak insulation, due to the lack of surface area. Maximum is -2 and minimum -26. Low angle of incidence, with very little snowfall in polar environments. Little rainfall.
• Vegetation - mosses and lichens grow around the edge, but other than that, no plants
• Soil - due to slow nutrient cycle, the soil is usually deprived of nutrients, poor vegetation causes poor soil and poor soil causes poor vegetation.

Question 28

What are the physical characteristics of alpine environments?

Answer 28

• Climate - temps fluctuate annually and summers are frequently above 0 DC. In winter, receive heavy snowfall and in summer, milder temps can lead to heavy rainfall and a lot of meltwater form snow and ice.
• Vegetation - vegetation thrives in milder summers and dies in winter. Quicker nutrient cycle, as wildlife uses vegetation for food and warmer climate encourages decomposition. Plants grow quicker.
• Soils - higher temps allow soils to thaw, increasing the area that vegetation can grow in. More fertile soils, due to nutrient rich vegetation- nutrient rich soils. Although freezes in winter.

Question 29

What are the physical characteristics of tundra environments?

Answer 29

• Climate - precipitation is low (but still occurs in summer months), temps are consistently below freezing. Max temp is 7, Min temp is -27.
• Vegetation - it needs to be above 6 DC for plants to grow. Very few plant species, so low biological diversity. Shallow roots as presence of permafrost with ability to photosynthesis at extremely low temps. Most flowering plants are perennials (flower year after year). Plants have to cope with thin soils and potentially severe water-logging on flat, poorly drained land.
• Soils - precipitation levels are low with soil moisture frozen for much of the year. It is a uniform blue grey colour which is very acidic and is waterlogged in the summer. Lacks minerals and rates of chemical and biological weathering are limited, so is availability of minerals required by plants. Rates of soil development are very slow so thin soils. Permafrost is either frozen or melts and saturates/water-logs the soil.

Question 30

What are some examples of species in Tundra environments?

Answer 30

• The Snow Buttercup and Artic Poppy - due to the short growing season, both of these produce flowers very quickly (while the snow is still melting) to maximise time for pollination.
• Bearberry - grows low to the ground to avoid harsh winds (3 inches av.) and is tolerant of low nutrient soils, also has fine silk hairs that grow on stem to retain warmth. As well as this, has leathery leaves to reduce evaporation.

Question 31

How is Conderious trees another example of a species in tundra environments?

Answer 31

• Evergreens in the Taiga tend to be thin and close together- protection from cold and wind
• Also have branches pointing towards the ground protecting them from breaking under weight of the snow.
• Evergreen to allow as much photosynthesis as possible due to the short growing season.
• Waxy needles give protection from freezing temps and from drying out.
• Needles are dark in colour, allowing them to absorb heat from the sun.

Question 32

What are some of the climate challenges facing plants in cold environments?

Answer 32

• Permafrost (frozen ground) creates an impermeable layer for roots and water most of the year.
• Poor drainage - the active layer of the permafrost thaws in summer lead to waterlogged ground and deoxygenation of plants
• Low insulation (sunlight and heat) due to latitude results in a short growing season confined to summer months. Complete darkness for winter months at high latitudes.
• Strong dry winds and low precipitation.

Question 33

How do glaciers form?

Answer 33

• year-round thick mass of snow (that does not entirely melt over the summer) - lots of snowfall in winter and cool summers
• Snow compacted (air squeezed out) to form firn which then becomes glacial ice)
• Glaciers = snow, firn and ice.

Question 34

How cold are glaciers?

Answer 34

Thermal regime - the temperature varies throughout a glacier, e.g. how it changes with depth.
- temps usually increase slightly with depth, due to:
- 1. Overlying ice pressure 2. Geothermal heat from the ground
- Although in some locations, surface will be warmer than base, e.g. temperate regions (e.g. Alps)

Question 35

What is the pressure melting point (PMP)?

Answer 35

• At the ground (under normal atmospheric pressure), the melting point of ice = 0 DC
• But, under pressure of ice, the melting point is lower (the PMP)
• If the temp drops below the PMP, ice will begin to melt.

Question 36

What is a warm based glacier?

Answer 36

Temperate regions (e.g. the Alps) - with fluctuating, warmer temperatures. In Alpine environments:
- thermal regime is just below freezing
- Big variations between Summer and Winter
- Summer = plenty of surface meltwater (approx 5 DC above freezing)
- Base - temp exceeds PMP and meltwater occurs - acts as a lubricant (allowing basal sliding) and internal deformation is also present. .
- Therefore erosion and scouring occurs and much of transportation of sediment.
- Winter = approx -10 DC with base being below 0 - less meltwater but still present

Question 37

What are cold based glaciers?

Answer 37

In Polar environments (e.g. Antarctica and Greenland) with a constant dry and cold climate:
- Summer = surface temp is -15 or colder with base temps being -10 or colder, well below PMP
- Winter = -20 - -30, sometimes colder on surface temp, for base temp its -10 or colder, so little change compared to summer
- Any movement is solely by internal deformation, very little basal sliding (if any)
- Therefore little erosion or transportation of sediment.