Unit 1

Question 1

Where are glaciers found and why are they important?

Answer 1

(a glacier is a moving body of ice)
They are found in cold areas of high altitude and latitude.
Important because: 1/3 of population rely on them for drinking water, tourism, recreation, irrigation and hydroelectric power.

Question 2

(Glaciers operate as an open system)
What are the inputs?

Answer 2

• accumulation zone, where snow falls at high altitudes which increases the mass
• avalanches and wind blown snow add mass
• de-sublimation (steam to ice)
• dirt zones (where ice is forced upwards)

Question 3

What are the outputs of glaciers?

Answer 3

• ablation zone, where melting occurs due to increased temperatures and run off
• deformation due to solar energy
• sublimation (ice to steam)
• decay of ice, moving blocks into the ocean

Question 4

What is the line of equilibrium?

Answer 4

Marks the zone where glacier accumulation is balanced with glacier ablation over a 1 year period (where ice forms)

Question 5

Are the inputs above or below the line of equilibrium?

Answer 5

Above

Question 6

Are the outputs above or below the line of equilibrium?

Answer 6

Below

Question 7

What is glacier mass balance?

Answer 7

The difference between inputs and outputs

Question 8

What is a positive mass balance? (zone of…)

Answer 8

inputs > outputs

… accumulation

Question 9

What is a negative mass balance?
(zone of…)

Answer 9

inputs < outputs

… ablation

Question 10

Which zone is greater in summer?

Answer 10

accumulation > ablation

Question 11

Which zone is greater in winter?

Answer 11

ablation > accumulation

Question 12

How does ice form in the zone of accumulation?

Answer 12

1. snowflakes fall, these contain air and have a low density
2. as more snow falls, pre existing snow compacts
3. snow that becomes compacted experiences freezing in the winter and thawing in the summer = firn/neve ice (composed of ice crystals separated by air passages)
4. in summer, meltwater percolates (moves down vertically) into firn
5. firn refreezes and the snowpack becomes increasingly dense
6. no. of years later, successive layers of snow and firn accumulate to a depth of 20m

Question 13

What is a glacial period? What is the mass balance like?

Answer 13

• Colder periods
• positive mass balance which leads to long term growth of glaciers

Question 14

What is an interglacial period? What is the mass balance like?

Answer 14

• Warmer periods
• negative mass balance leads to long decay and the retreat of the glacier

Question 15

What was the name of the last glacial period? What area does it cover?

Answer 15

Devensian - covered most of Northwest Europe

Question 16

What is the quaternary period?

Answer 16

A geological period representing the last 2.6 million years

Question 17

What is an epoc? What was the last one called?

Answer 17

• smaller glacial/interglacial periods within a geological period
• holocene

Question 18

What is present day Earth’s orbit like?

Answer 18

• 365 1/4 days
• axis = tilted towards sun
• angle = 23.5 causing seasonal variation in climate
• axis changes between the tropics of cancer and capricorn

Question 19

What are the Milankovitch Cycles?

Answer 19

1. Stretch (eccentricity) of orbit
2. Axis tilt (obliquity)
3. Wobble (precession)

Question 20

What is stretch (eccentricity)?

Answer 20

• time frame = 100,000 years
• shape of the orbit e.g circular or oval
• this affects the amount of solar radiation that reaches the Earth

Question 21

What is axis tilt (obliquity)? What is the affect on climate?

Answer 21

• time frame = 41,000 years
• over the last million years, tilt has varied between 22.1 and 24.5
• affects on climate
  = makes seasons milder
  = warming winters / cooling summers
  =allows snow and ice at high altitudes to build up into ice sheets

Question 22

What is wobble (precession)?

Answer 22

• time frame = 25,771.5 years (26,000)
• affects the position of the seasons on orbit

Question 23

What do feedback mechanisms do to glacial mass balance systems?

Answer 23

they can either amplify or diminish changes in the system

Question 24

What is positive feedback? How does this affect glaciers?

Answer 24

• positive feedback can amplify changes in the glacial budget
• cooling leads to further cooling -> meaning snow and ice cover increases meaning it raises the surface albedo (reflectivity) of the Earth’s surface.
• more solar energy is reflected back

Question 25

Explain how positive feedback operates when milankovitch cycle starts cooling.

Answer 25

1. cooling of climate 2. arctic sea freezes so ice cover increases 3. increases number of lighter surfaces 4. albedo increases = more reflection 5. increases reflection of solar radiation and decreases of absorption

Question 26

What is negative feedback? How does this affect oceans?

Answer 26

- negative feedback can reduce/diminish changes in the glacial budget - warming can also lead to cooling e.g disruption to the thermohaline ocean current circulation

Question 27

Explain how warming can lead to the development of interglacial periods.

Answer 27

1. warming leads to increased temperatures 2. arctic sea melts 3. darker surfaces revealed 4. albedo is reduced (less reflective surfaces) 5. increased absorption of solar radiation

Question 28

Explain how thermohaline ocean circulation works.

Answer 28

- low density freshwater drains to into North Atlantic - high density saline warm North Atlantic drifts, ocean current forced to descend further south - Warmth from North Atlantic drift ocean current shut off to North West Europe, reducing temperatures -

Question 29

What is solar forcing? What are solar spots?

Answer 29

(refers to energy released by the sun) solar output linked to solar spots solar/sun spots are areas of high solar output which fluctuate on an approx. 11 year cycle

Question 30

Is solar forcing a long-term or short-term cause of climate change?

Answer 30

short-term

Question 31

When was the little ice age and what was it known as?

Answer 31

between 1645 and 1715, a period known as the 'Maunder minimum' occured with low levels of solar output

Question 32

What happened during the little ice age?

Answer 32

- sea ice expanded far south making it impossible to ship things to Iceland and Greenland - Baltic sea and River Thames froze over - increased amount of permanent snow in high altitude areas of Scotland

Question 33

What are volcanic eruptions? How do they affect the climate?

Answer 33

explosive eruptions propel Sulphur dioxide and ash into the atmosphere, where they reflect incoming solar radiation... therefore can cause cooler conditions and lead to global cooling

Question 34

Are volcanic eruptions Long-term or short-term cause of climate change?

Answer 34

short-term

Question 35

What is meant by an anthropogenic factor?

Answer 35

human activity/ factors

Question 36

How has human activity affected climate change?

Answer 36

human activity e.g agriculture, deforestation, fossil fuel usage has lead to the increase in conc. of greenhouse gases in the atmosphere resulting in the increase of global temperatures

Question 37

How much has the average temperature increased since 1880?

Answer 37

1.2 degrees

Question 38

What is present day ice cover like?

Answer 38

glaciers cover more than 10% of Earth's land surface (stores 75% of freshwater)

Question 39

How is present day ice cover different to ice cover 10,000 years ago?

Answer 39

- sea ice has retreated further north - U.K, Norway, Finland and Sweden no longer covered in ice - sea levels rising, affects coastlines

Question 40

Why are glaciers found at high altitudes? An example of a high altitude location?

Answer 40

because there is an increase of accumulation due to higher temperatures e.g. the alps

Question 41

Why are glaciers found at high latitudes? An example of a high latitude location?

Answer 41

because there is a bigger surface area, which means the solar energy is spaced out , less absorbed in one spot e.g. the arctic