Enquiry question one

Question 1

Who discovered ice ages and how?

Answer 1

Louis Agassiz - 1830s
In the Swiss Alps
He noticed that certain areas had similar features

Question 2

What is Uniformitarianism?

Answer 2

The assumption that the same natural laws and processes that operate in our scientific observations now have always operated in the universe in the past and apply everywhere

Also known as the Doctrine of Uniformity or the Uniformitarian principle

Question 3

What are ice cores and how do they help us?

Answer 3

They are large cylinder samples of ice
Bubbles trapped in the ice contain CO2 from the atmosphere
Low conc = glacial periods
High conc = interglacial periods

Question 4

What period do we currently live in?

Answer 4

Quaternary period - started 2.588 million years ago

Question 5

What are epochs?

Answer 5

Periods of geological time - relating to times where geological strata were laid down
They denote changes during the Earths time e.g mass extinctions

Question 6

What are the different epochs of the Quaternary period?

Answer 6

Pleistocene - the beginning of the period about 2,588,000 to 11,700 years ago
Holocene - an interglacial period, age of man
Anthropocene - from 1950 starting when there was significant human impacts of Earth until now

Question 7

Why is it hard to reconstruct the past using glacial landscapes?

Answer 7

Each time a glacial period occurs, the previous features and landforms are remoulded

Question 8

What are geomorphological processes and their impact?

Answer 8

Types of Mechanical, Chemical and Biological weathering

Question 9

How often do glacial periods occur?

Answer 9

Round about every 100,000 years

Question 10

What are stadial and interstadial periods?

Answer 10

Stadial - A short period of intense cold
Interstadial - A short period of intense warmth (relative to the intense cold)

Question 11

What are the Milankovitch theories (long term) on the causes of glacial cycles?

Answer 11

Eccentricity of orbit - Changes from elliptical to more circular orbit and back every 100,000 years approx. Low eccentricity = low seasonality, so promotes glaciation

Axial tilt/Obliquity - varies between 22.8 and 24.4 degrees over 41,000 years. Impacts the intensity of light hitting the poles. Low obliquity = low seasonality

Wobble/Precession - The Earth wobbles on its axis over a 21/22,000 year cycle. ⬆️ in the variation of irradiation of the N hemisphere —> Causes summer and winter temperature variation —> variations in ice volume. Precession works with eccentricity to control the level on insolation at 65 degrees N. Glaciation favorited when N.hem summer are at the largest earth-sun distance

• These three come together to minimize the amount of solar energy reaching the N.hem in the summer
• cooler summers means less ice melts, allowing it to build up

Question 12

What are feedback mechanisms?

Answer 12

Positive - climatic feedback can either amplify a small change
Negative - or diminish the change and make it smaller

Question 13

Example of positive feedback?

Answer 13

1) Small increases to snow and ice cover can increase surface albedo
2) More solar radiation is reflected back into space
3) Could lead to more snow and ice cover

Question 14

Example of negative feedback?

Answer 14

1) increased global warming & industry —> more evaporation—> increase in cloud cover
2) Increased cloud cover reflects solar energy back into space
3) Reducing intensity of global warming

1) Ice sheet dynamics disrupt THC
2) Warming waters in the Arctic disrupts ocean currents
3) Less warm water from the gulf stream creating global cooling in N.Europe

Question 15

What are the short term factors that cause climate change?

Answer 15

Solar forcing:
Energy emitted by ☀️ varies due to ☀️spots.
cycles every 11 years
reliable records dating back 400yrs
Maunder minimum - 1645 - 1715 - little ice age, temp = 1 degree lower than today
Medieval warm period - 950 - 1250 - temp = 1 degree hotter than today

Volcanic causes:
Volcanoes have altered temperature
Highly explosive volcanoes (VEI 7+) eject huge amounts of ash, sulphur dioxide, CO2, and water vapor into the atmosphere
spreads globally, blocking out sunlight (global dimming)
1815- Tambora in Indonesia: temps dropped by 0.4-0.7 degrees for 2-3 years

ENSO cycles

Question 16

Case study—> Loch Lomond Stadial

Answer 16

( Younger Dryas event )
- occurred 11,700BP to 12,900BP
- ice sheets began melting 18,000BP
- rapid deglaciation 15,000BP ago due to similar temps as today
- 12,500BP glacial conditions reoccurred and by 11,500BP temps were 6-7 degrees lower than today
- glaciers readvanced all over the world inc scotland, lake district and snowdonia

Reason: believed to be due to the draining of Lake Agassiz ( glacial lake in N. America) into Atlantic disrupting the THC (Thermohokine circulation) by cutting off the poleward heat from the gulf stream

Question 17

Case study —> The little ice age

Answer 17

Proxy records - tell us that between 1550 - 1750 there was a trough of cold temps (perhaps 1-2 degrees lower) having many impacts

Abandonment of many hill farms in n europe
glaciers advanced down valleys
arctic sea ice spread further south with polar bears found in Iceland
rivers froze in UK, lowland europe and NYC
curling developed in scotland

argued that it never developed into a full blown stadia due to the onset of the industrial revolution GHGs creating a warming effect

Question 18

What is the Cryosphere?

Answer 18

The parts of the Earths crust and atmosphere subject to temps below 0 degrees for some part of the year

2 roles:
- help regulate climate via the albedo effect
- it is a global store of freshwater

Question 19

What are the different ice masses?

Answer 19

Ice sheet - a layer of ice covering an extensive tract of land for a long period 10-100,000 km2
Ice cap - miniature ice sheets in polar and sun polar regions that are relatively flat and high in elevation 3-10,000
Ice field - large expanse of ice covering a mountainous region and consisting of several interconnected glaciers 10-10,000
Valley glacier - glacier confined by valley walls 3-1500
Piedmont glacier - occur when steep valley glaciers flow onto relatively flat plains, where they spread out into lobes 3-1000
Cirque glacier - named for the bowl like hollows they occupy: cirques 0.5-8
Ice shelf - floating sheet of ice permanently attached to a land mass 10-10,000

Question 20

What’s the difference between constrained/unconstrained glaciers?

Answer 20

Constrained - Have a physical limit such as valley glaciers where the landscape constrains where they are & tend to only drain one way

Unconstrained - Tend to be larger forms e.g ice sheets & caps. Thick, extensive and often submerge the landscape

Question 21

What are the the two main types of glaciers?

Answer 21

WARM BASED 🔥
- other names: temperate, wet, alpine
- occur at high altitudes (outside of polar regions)
- water exists undersurface at temps below 0 due to a build up of pressure
- this melt water causes them to melt continually —> basal ice (ice at bottom of glacier)
- also has lots of debris at bottom, creating many subglacial deposits and landforms

COLD BASED 🥶
- occur in polar regions
- surface temps of -20 to -30 meaning temp at base still below 0
- limited surface melt in polar summer, so glacier is permanently frozen to the bed
- therefore basal layer has far less debris within it

Question 22

What are the other two types (don’t really need to know)

Answer 22

Polythermal glacier -
Warm based but the margin is cold based
upper zone is cold based whilst the lower zone is cold based
due to extending into warmer climate zones
e.g glaciers on Svalbard

Surging glaciers -
can occur within warm based or polythermal glaciers
can flow at up to 100m a day
greenland outer glacier - 30m a day
leads to increased calving

Question 23

What is the pressure melting point?

Answer 23

Defined as the temperature at which ice begins to melt under a given amount of pressure
Water melts at 0 degrees under ordinary atmospheric conditions
At hugger pressures, the melting point is lower
Allowing it to remain a liquid at below its normal freezing point

Question 24

Describe the graphs

Question 25

Where is most of the worlds glaciers found?

Answer 25

85% in Antarctica
rest is distributed among:
iceland
canada
usa
himalayas
andes
alps

Question 26

Glacier significance facts

Answer 26

Covers 10% of earths land surface
accounts for 75% of all freshwater stores
and 1.8% of all water on the planet

Question 27

Why do glaciers form at high latitudes and altitudes?

Answer 27

Latitudes: the suns rays hit at a lower angle —> the solar energy received has to heat a larger area
Altitude: impacts on temp due to the environmental lapse rate —> the rate at which temp decreases with altitude at a given time - approx 1% for every 100m

Question 28

What is aspect and what does it determine? (along with relief)

Answer 28

It is the direction a cirque faces - determines the amount of snow that settles
Relief & aspect in mountainous areas combine to affect where cirques form
North & East slopes are more sheltered and receive less sunlight so are better able to hold snow

Question 29

What is the past cover of glaciated landscapes like today compared to the past cover?

Answer 29

During pleistocene - the max was about 3x more than today
North America (Laurentide and Cordilleran ice sheets) and Scandinavian ice sheets grew to a thickness of 3000-4000m
Also glaciers in South America, New zealand, Himalayas and siberia

Question 30

CASE STUDY - Mer de glace - french alps

Answer 30

Located on the Mont-Blanc massif

**Size & threats: **
- covers an area of 30km2 and stretches 12km in length, reaches thickness of 300m
- largest in france, 3rd largest in the alps
- climate change = causing rapid thawing
- each year it shortens by 30-40m & loses 4-5m of thickness downstream
Since 1850 - withdrawn by 2km
Scientists predict another 1.2km by 2040

**Importance & Impact: **
- crucial role in regulating hydrological flows and global climate
- contribute to rising sea levels
- if glaciers disappeared = disastrous consequences for biodiversity

Rights of nature:
- glaciologists estimate it has good odds of surviving if we manage to mitigate global warming
- could retain up to 70% of current volume, by adhering to climate commitments
- without action, may lose over 90%

Ecosystem of impact:
- glaciers balance affects the entire surrounding alpine ecosystem
- climate change continues to pose a significant threat & efforts to protect them our crucial for our planets future