Unit 1 Notes

Question 1

Why are glaciers important for people?

Answer 1

They provide drinking water, help to irrigate crops, can be used for hydroelectric power. 1/3 of the population rely on them.

Question 2

What is happening to glaciers around the world?

Answer 2

They’re shrinking.

Question 3

How much have sea levels risen by?

Answer 3

2.6cm.

Question 4

Where are glaciers found?

Answer 4

Cold areas, close to the poles, at high altitudes.

Question 5

What is mass balance?

Answer 5

The difference between glacial inputs and outputs.

Question 6

What happens when inputs are more than outputs?

Answer 6

A glacier advances.

Question 7

What happens when outputs are more than inputs?

Answer 7

A glacier will retreat.

Question 8

What is the zone of accumulation?

Answer 8

Higher altitude areas where inputs are more than outputs.

Question 9

What is the zone of ablation?

Answer 9

Lower altitude areas where outputs are more than inputs.

Question 10

What is the line of equilibrium?

Answer 10

Where mass balance is equal.

Question 11

What happens to zones during summer?

Answer 11

Zones shift to higher altitudes, zone of ablation increases, zone of accumulation decreases.

Question 12

What happens to zones during winter?

Answer 12

Both zones shift to lower altitudes. Zone of accumulation increases, zone of ablation decreases.

Question 13

What are the inputs of a glacier?

Answer 13

Things which add to the mass of a glacier.

Question 14

What are the examples of inputs?

Answer 14

Snow, Avalanches, Freezing rain, debris wind, wind-blown snow.

Question 15

Where are inputs concentrated?

Answer 15

Towards the head of a glacier.

Question 16

What are the outputs of a glacier?

Answer 16

Things which are lost, making a glacier smaller.

Question 17

What are the examples of outputs?

Answer 17

Meltwater, sublimation, calving, rock debris.

Question 18

Where are outputs concentrated?

Answer 18

Towards the toe of a glacier.

Question 19

What happens to pre-existing snow when snow falls?

Answer 19

It compacts.

Question 20

What percentage of glaciers are in negative mass balance?

Answer 20

75%.

Question 21

What effect does negative mass balance have on the world’s systems?

Answer 21

Increasing global warming, changes to the earth’s albedo, causes sea levels to rise.

Question 22

Are we in a glacial or interglacial period now?

Answer 22

Interglacial.

Question 23

What is the mass balance of glaciers during a glacial period?

Answer 23

Positive mass balance, meaning they can grow and develop into ice sheets.

Question 24

What was the last glacial period?

Answer 24

The Devensian period.

Question 25

How far along does the Quaternary period stretch?

Answer 25

The last 2.6 million years.

Question 26

What were the last 5 geological periods?

Answer 26

Holocene, Devensian, Ipswichian, Wolstonian, Hoxnian.

Question 27

When does a glacier have a negative mass balance?

Answer 27

Between late spring and early autumn.

Question 28

Why does a glacier have a negative mass balance at this time?

Answer 28

Temperatures at this time of year are at their highest.

Question 29

When does a glacier have a positive mass balance?

Answer 29

Between late autumn and early spring.

Question 30

Why does a glacier have positive mass balance at this time?

Answer 30

Temperatures at this time of year are at their lowest, reducing rates of ablation.

Question 31

What happens to the snow after a number of years?

Answer 31

Successive layers of snow and firn accumulate to a depth of 20 metres, and most of the air is squeezed out.

Question 32

What determines the rate at which this happens?

Answer 32

Depends on the mass balance equation.

Question 33

What happens to the density of the snow in summer?

Answer 33

It becomes more dense, as meltwater percolates into firn, and refreezes.

Question 34

What is firn separated by?

Answer 34

Air passages.

Question 35

What is firn snow?

Answer 35

Snow which has compacted after a winter's freezing, and a summer's melting.

Question 36

What is the density of snow like?

Answer 36

Low.

Question 37

What is the cause of the long term cyclical change?

Answer 37

Changes in the earth's orbit around the sun, leading to variation in the intensity of insolation.

Question 38

What are the three types of Milankovitch cycles?

Answer 38

Stretch, Tilt, Wobble.

Question 39

How long do stretches last?

Answer 39

100,000 Years.

Question 40

What is the difference in insolation between the closest and farthest point from the sun?

Answer 40

23%.

Question 41

What does the axis tilt vary from?

Answer 41

22.1-24.5 degrees.

Question 42

What does the timeframe vary from of tilts?

Answer 42

40,000 Years.

Question 43

What does it mean if the tilt is greater or less extreme?

Answer 43

Greater Tilt - More extreme seasons. Lesser Tilt - Less extreme seasons.

Question 44

How long does one wobble cycle last?

Answer 44

25,000 Years.

Question 45

What is the Albedo Effect?

Answer 45

Cooling of the earth, through sea ice building up, lighter surfaces being created, meaning albedo increases, and sun's rays are reflected to the atmosphere.

Question 46

What happens to the albedo when temperature increases?

Answer 46

Sea ice melts, darker surfaces are revealed, less of sun's rays are reflected, temperature increases further.

Question 47

What is the negative feedback loop?

Answer 47

The idea that an initial change in the glacial budget can bring around lots of other changes as a result.

Question 48

Why is water in NW Europe warm and salty?

Answer 48

Initial warming can lead to cooling through thermohaline current.

Question 49

What is the average winter temperature in England vs. Russia?

Answer 49

England - 5 degrees. Russia - -8 degrees.

Question 50

How does the amount of salt in the water affect the density?

Answer 50

Salty water is more dense.

Question 51

How does the temperature of the water affect the density?

Answer 51

Cold water - More dense - sinks. Warm water - less dense - rises.

Question 52

What happened towards the end of the Devensian period?

Answer 52

Temperatures were rising, which eventually led to cooling, as it caused disruption in the ocean current.

Question 53

How long did the younger dryas period last?

Answer 53

2000 Years.

Question 54

What happened to temperature and ice accumulation during the younger dryas period?

Answer 54

Temperature dropped by 15 degrees, Ice accumulation went from 0.75 metres per year to 0.34 metres per year.

Question 55

What did the changes in insolation mean?

Answer 55

Icebergs were released into the North Atlantic ocean, reducing density of the remaining ice sheets, ice started retreating.

Question 56

What factors affect short term climate change?

Answer 56

Solar forcing, volcanic eruptions, anthropogenic factors.

Question 57

What is solar forcing?

Answer 57

The idea that the amount of energy released by the sun changes and is linked to sun spot activity.

Question 58

What are sun spots?

Answer 58

Areas of high solar output which fluctuate on an 11 year cycle.

Question 59

What is an example of low solar output?

Answer 59

The maunder minimum. Sea ice expanded, Baltic sea froze over. Most of the rivers in Europe also froze over.

Question 60

How do volcanic eruptions affect climate change?

Answer 60

Sulphur dioxide and ash are released into the stratosphere, reflecting incoming solar radiation.

Question 61

What are the examples of volcanic eruptions?

Answer 61

Laki in Iceland - 1783 - -3 degrees below average. Fambora - 1815 - 0.7 degrees below average.

Question 62

How do anthropogenic factors affect climate change?

Answer 62

Human activity increases the concentration of greenhouse gases, meaning average global temperature has risen by over 1.2 degrees since 1880.

Question 63

Why have Antarctic regions warmed by the most?

Answer 63

They have warmed by 4.5 degrees, due to the albedo of these environments changing, causing a negative feedback loop.

Question 64

What are the only two ice sheets left?

Answer 64

Greenland and Antarctica.

Question 65

What were ice sheets like during the Devensian maximum?

Answer 65

There were 7 ice sheets, and they were bigger.

Question 66

What has happened to sea levels as a result of ice sheets shrinking?

Answer 66

Sea levels were 130 metres lower then, than they are now.

Question 67

Why are glaciers found at high latitutdes?

Answer 67

Lower temperatures are found here, so the sun's rays are less focused.

Question 68

Why are glaciers found at high altitudes?

Answer 68

As warm air rises, it's under less pressure, expands, and temperature drops as a result.