Glacial Characteristics

Question 1

What is glacial budget?

Answer 1

The balance between a glacial input and output

Question 2

What is positive glacial budget?

Answer 2

When there is more accumulation than ablation
- the glacier advances

Question 3

What is negative glacial budget?

Answer 3

When there is more ablation than accumulation
- the glacier retreats

Question 4

How will the seasons affect glacial mass balance?

Answer 4

Summer = hotter,more ablation. Negative glacial budget.

Winter= colder, more accumulation. Positive glacial budget.

Question 5

What influences the short term change in glacial budget?

Answer 5

Seasons

Question 6

What influences the long term change in glacial budget?

Answer 6

Climate Change (driven by humans)
Stadials and interstadials
Glacials and interglacials

Question 7

How does human-driven climate change influence the long term glacial budget?

Answer 7

• increased fossil fuel consumption causes the enhanced greenhouse effect
• increased GG in atmosphere insulates the Earth more
• more solar energy is absorbed = the Earth warms
  = GLOBAL WARMING
• as the avergae temperature is higher, outputs from the glacier increase. NEGATIVE GLACIAL BUDGET, the glacier will retreat
• positive feedback loops ensures this continues to happen even more

Question 8

What is a positive feedback?

Answer 8

a process within a system where an initial change triggers a series of events that enhances/amplifies the change

-pushes the system further away from the equilibrium state (snowball effect)

Question 9

What is negative feedback?

Answer 9

a process within a system to counteract the initial change and bring the system back to an equilibrium state

Question 10

Give an example of positive feedback influenced by climate change

Answer 10

The albedo effect

Question 11

What is the albedo effect?

Answer 11

Albedo = reflectivity of the Earth’s surface

Climate change warms temperatures - leads to increased melting of the glaciers

• Increased melting means there are more darker surfaces
• Increased darker surfaces mean less solar radiation is reflected/more is absorbed
• this leads to warming temperatures
• which leads to more melting … (etc)

Question 12

What is a glacial?
When was the last one?

Answer 12

A period of time where the temperatures of the Earth are low enough for the Earth’s surface to be covered in ice due to the advance of glaciers

• part of an ice age: can last for thousands of years. Last one was the Pleistocene - 100,000YA-10,000YA

Question 13

What is an interglacial?
When was the most recent one?

Answer 13

A period of time within an ice age where the temperature of the Earth increases and glaciers retreat

• currently in an interglacial = Holocene. 10,000YA - present

Question 14

What are stadials and interstadials?

Answer 14

Phases that divide the Quaternary period

Question 15

What is a stadial?

Answer 15

• a substage of a glacial stage marked by ice advancing again
• a period of colder climate withing a glacial

Question 16

What is an interstadial?

Answer 16

• a substage of a glacial stage marked by ice retreating again
• a period of warmer climate within a glacial

Question 17

What is a cause of long term climate change? (Not human caused)

Answer 17

Milankovitch theories

Question 18

What are the Milankovitch theories?

Answer 18

Eccentricity
Obliquity
Precession

Question 19

What is eccentricity?

Answer 19

The degree of variation of the Earth’s orbit around the sun from circular to more elliptical
- over a period of around 68,000Y

Question 20

How does a circular orbit affect climate change?

Answer 20

• lower temp difference between seasons
  = GLACIAL - ice can be sustained because steady temperatures allow accumulation

Question 21

How does elliptical orbit affect climate change?

Answer 21

• higher temp difference between seasons
  = INTERGLACIAL - ice cannot be sustained because fluctuating temperatures donot allow steady accumulation and compaction

Question 22

What is obliquity?

Answer 22

The angle that the Earth’s axis is tilted as it orbits the sun
- the reason the Earth has seasons
- angle of tilt has varied between 22.1 and 24.5 degrees over the past million years

Question 23

How does obliquity affect glacial and interracial periods?

Answer 23

INCREASED TILT
- tropics will get wider
- summers will be hotter
- winters will be colder
- the increased temperature difference = more extreme
so it favours INTERGLACIAL because ice cannot be maintained in the landscape, therefore glaciers cannot advance

DECREASED TILT
- tropics will get narrower
- summers will be colder
- winters will be warmer
- the decreased temperature difference = less extreme
so it favours GLACIAL because snowfall can persist in the landscape. feedback loops will kick in, the ice will compact, and we will enter a glacial period

Question 24

What is precession?

Answer 24

The slow, gradual wobble or shift in the orientation of the Earth’s rotational axis over a time span of around 26,000 years

• Earth is closest to sun (perihelion) currently during Northern Hemisphere winter, but this will shift so it occurs during summer

Question 25

How does precession affect climate change?

Answer 25

• it alters the intensity and distribution of solar insolation reaching different parts of the planet throughout the year
• as it changes, it changes the patterns of seasons and advance and retreat of ice ages

Question 26

How can volcanos have a short term effect on climate change?

Answer 26

AEROSOLS IN ATMOSPHERE = increased absorption of sunlight which caused global dimming and the temperatures drop