Transcript Rivers - Hydrological cycle (P.6)

This is a focussed revision guide for use closer to
the final exam – a star* next to the slide number
indicates a slide you must become an expert
about as the exam approaches
Ideas how to use the revision cards:
- Colour code the cards to show how confident you are with
the topic
1
- Ask someone at home to test you
- Test yourself & highlight key words
- Annotate (label) the cards
- Re-write your own definitions
- ‘Look, cover, check’
- Draw a mind map for some topics
- Expand on key words
- Explain a topic to someone else
- Cut out cards & stick around a room
64*
Extreme
Environments
Mountain
Environments
What do we know
about mountains?
What a mountain environment is like – physical characteristics:
Mountain ranges are considered to be extreme environments due to their height
and the difficulties people face living in them.
Altitude – mountains are over 610m above sea level – the higher you climb the less
oxygen there is – muscles become less efficient and it is difficult to move.
Terrain – moving around is difficult due to the steep gradients – steep-sided
mountain slopes and valley sides.
Weather and climate – weather can change very quickly due to relief rainfall –
cumulonimbus clouds gather quickly because warm air is pushed over mountains –
the air cools and water vapour condenses forming clouds which soon turn into storm
clouds. Storms can last a few hours or a few days. Snow is common – snow and ice
at altitude make travelling hard. It is also colder the higher up you are and you can
also be exposed to strong winds.
65*
Extreme
Environments
Mountain
Environments
What do we know
about mountains?
The Andes – mountain environments have an impact on humans:
At 7000km long the Andes run through Peru, Bolivia, Argentina, Columbia,
Ecuador and Chile.
Economic activity:
Low population density of about
1-10 people per sq/km:
• very low densities in the high
Andes where living conditions are
most difficult
• highest densities on the
Altiplano – a plateau (flat land
high up in the Andes) still sparsely
populated despite being home to
the world’s highest city – La Paz
in Bolivia (population 2 million and
growing rapidly)
The Altiplano is home to the
Aymara Indians – subsistence
farmers (grow just enough for
themselves) who struggle to
scrape a living in the harsh
environment.
Aymara Indians – main job is
agriculture - they farm potatoes and
quinoa (a grain crop) on steep
mountain sides. This makes farming
difficult so it is all done by hand. Alpaca
farming: alpaca fibre and meat are
exported to places around the world although it is not as profitable as it used
to be.
Tourism: tourists visit many places in
Andes including Machu Picchu & for
hiking, climbing and fishing holidays in
Patagonia.
Energy production: Energy is created
through a few large scale hydro-electric
dams located in Patagonia. This
supplies electricity to many of the cities
in the Andes.
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Extreme
Environments
Mountain
Environments
Where are
mountains found?
Mountains are found on
most continents – those in
red are mentioned in the
specification:
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
Alps
Andes
Appalachians
Asir Mts
Atlas Mts
Balkan Mts
Caucasus
Drakensberg
Ethiopian Highlands
Great Dividing Range
Himalayas
Pyrenees
Rockies
14. Zagros Mts
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Extreme
Environments
Mountain
Environments
Where are
mountains found?
• The Andes mountain range is located to the
west of South America. They are located
between the Nazca and South American plates
and run through countries such as Peru, Chile
and Ecuador.
• The Alps mountain range is located in central
Europe. The mountains are in the middle of
the Eurasian plate and run through countries
such as France, Italy and Austria.
• The Himalayas are located in south Asia between the Indian and Eurasian
plate. They are the highest mountain range in the world.
• The Atlas mountains are located in north west Africa between the African and
Eurasian plates. They are located in Morocco and the Sahara desert.
• The Great Dividing Range is in east Australia on the Indian tectonic plate.
• The Pyrenees are located between Spain and France.
• The Rockies are in the west of North America – they are found between the
Pacific and North American plates.
68*
Extreme
Environments
Mountain
Environments
Where are
mountains found?
There are different types of plate
boundaries:
• constructive (divergent)
• destructive (subduction)
• collision
• conservative
Different plate boundaries have
different physical processes
associated with them:
• faulting
• folding
• volcanic activity
• earthquakes
The strongest link is between the location of mountains and destructive
plate boundaries – pay particular attention to slide 70.
69
Extreme
Environments
Mountain
Environments
Where are mountain
environments
found?
A constructive (divergent) plate boundary – e.g. Mid-Atlantic Ridge –
middle of the Atlantic Ocean.
• plates are moving apart
• new crust is constructed as
magma (molten rock) from the
mantle reaches the surface
through the gap between the
plates – volcanoes erupt
• earthquakes are created by
the friction between the mantle
and the moving plates
• crust on either side of the
boundary is often faulted –
there are big cracks in it caused
by the massive pressures that
the moving plates create
70*
Extreme
Environments
Mountain
Environments
A destructive (subduction) plate boundary
Where are mountain
environments
found?
e.g. The
Andes are
on the
boundary
between the
Nazca and
South
American
plates.
Convection currents in the
mantle make the 2 plates move
together – the heavier oceanic
Nazca Plate pushes under the
continental South American
Plate = SUBDUCTION.
In the subduction zone the Nazca plate melts in the mantle creating magma – this rises
to the surface where it erupts as lava – volcanoes. The South American plate is also
crumpled into fold mountains. Friction between the plates also causes earthquakes.
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Extreme
Environments
Mountain
Environments
Where are mountain
environments
found?
A collision plate boundary - e.g. the Himalayas
• two continental plates push into
each other
• they are the same density (unlike
the continental and oceanic plates
that meet at a destructive
boundary) so neither of them sink
into the mantle below
• they squeeze upwards forming
fold mountains
• the massive pressures caused by
two plates crashing into each other
causes earthquakes
• no space for magma to rise from
the mantle layer = no volcanoes
72
Extreme
Environments
Mountain
Environments
Where are mountain
environments
found?
A conservative plate boundary - e.g. San Andreas Fault on the west coast of
North America.
• plates move past each other
• friction between the plates
causes earthquakes
• no volcanoes because there
is no space for magma to rise
from the mantle layer
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Extreme
Environments
Mountain
Environments
Where are mountain
environments
found?
Key terms – to understand what happens at plate boundaries you
need to remember the following:
• crust – the solid, outer layer of the Earth – made up of continental and
oceanic plates.
• mantle – the area of molten (melted), hot rock under the crust – it is
made up of a thick liquid called magma (known as lava if it reaches the
surface) – hot rock in the mantle rises, and sinks again as it cools – these
convection currents cause the plates of the crust to move.
• folding and faulting – along with volcanic activity (magma rising to the
surface, erupting as lava and solidifying), these lead to the formation of
mountains – folding is when the rocks of the Earth’s crust bend; faulting
is when they break or crack.
74*
Extreme
Environments
Mountain
Environments
Where are mountain
environments
found?
Mountains are found in ranges along
plate boundaries. Movement of the
plates leads to mountain building:
Fold mountains – under extreme
pressure and heat rock becomes
pliable – when two plates meet the
layers of rock are slowly crumpled.
As a result sedimentary rock formed
under the sea can be found above sea
level millions of years later in the form
of mountains – the rocks fold upwards
forming mountains.
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Extreme
Environments
Mountain
Environments
Where are mountain
environments
found?
A fault occurs when pressure at plate
boundaries is so great that blocks of rock
break apart. This process can occur very
rapidly creating earthquakes. The damage
caused by this can be very destructive and
cause severe changes to the Earth’s surface.
Faults rarely occur on their own – they often
occur together and are parallel to each other –
this can lead to the formation of mountains.
76*
Extreme
Environments
Mountain
Environments
Where are mountain
environments
found?
Mountains created by faulting - Rift Valley
• A rift valley is created when
two faults occur parallel to
each other and the land sinks
between them. The
mountains on either side of
a rift valley are called block
mountains.
• Examples include the Great
Rift Valley in North Africa and
the Black Forest Mountains in
Germany.
77*
Extreme
Environments
Mountain
Environments
What are mountain
climates like?
1 The higher the altitude (height
above sea level) the colder it gets
– about a 0.6c fall in temperature
for every 100m you go up.
2 The higher the altitude the
thinner the atmosphere is (less
oxygen in the air) due to less
pressure.
3 Mountains act as a barrier to the wind – weather on the windward
side can be quite different from the weather on the leeward side –
the west-facing slopes of the Andes are drier and more sheltered
than the east-facing slopes.
4 The aspect (direction in which you face) is important – e.g. east
facing slopes get sun in the morning but not the afternoon.
78*
Extreme
Environments
Mountain
Environments
What are mountain
climates like?
5 Mountains force air to rise and cool – condensation occurs forming clouds –
storms with rain or snow (precipitation) are likely the higher up you are – this is
called relief
rainfall:
The air gets forced up and over
the (windward) side of the
mountain. As the air rises, it
cools, condensation occurs,
clouds form and it rains. The air
sinks down the other (leeward)
side of the mountain – there is
little moisture left in the air. The
air also warms, evaporation of
remaining moisture occurs so no
clouds form = no rain.
rainfall =
400800mm a
year
drier west
side in the
rain
shadow
Atacama
Desert
Andes
moist,
easterly
wind
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Extreme
Environments
Mountain
Environments
What are mountain
landscapes like?
Glaciers – a glacier is a mass of ice
that moves slowly downhill under
gravity.
80*
Extreme
Environments
Glaciers erode the
landscape using 2
processes:
Abrasion – the
moving ice uses bits
of rock that it carries
to wear away at the
surface of the rock
below.
Plucking – as water
freezes it attaches to
pieces of rock to the
ice. When the
glacier moves the
pieces of rock are
pulled with it.
Mountain
Environments
What are mountain
landscapes like?
The landscape is also affected by
freeze-thaw weathering (frostshattering):
During the warm day, melt water
sinks into cracks in the rock. At
night the water freezes, expands
(by 10%) – the process is
repeated and eventually breaks
off pieces of rock.
This rock can be used by the
glacier for abrasion.
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Extreme
Environments
Mountain
Environments
What are mountain
landscapes like?
Freeze-thaw weathering on the mountain side can lead
to the formation of scree – a collection of broken rock
fragments at the base of the slope. This rock can be
used by a glacier for abrasion.
82*
Extreme
Environments
Mountain
Environments
What are mountain
landscapes like?
This is a CORRIE (sometimes called a cirque or tarn) – a bowl-shaped hollow with a
steep back wall and a shallow lip at the front – a small lake often forms in the corrie
bowl. Corries are usually found in the mountains and are formed by ice erosion –
when the ice has gone you are left with the landform below:
Steep,
frostshattered
back wall
Corrie lip
Corrie
lake or
tarn
83*
Extreme
Environments
Mountain
Environments
A corrie forms in stages – A, B, C & D below:
Base of hollow
deepened by
abrasion and
plucking
Less erosion
leaves lip –
material
deposited on lip
Steep, frostshattered back
wall
Corrie lake
Corrie lip
What are mountain
landscapes like?
Back wall made steeper by
erosion/weathering
84*
Extreme
Environments
If 2 corries
form side
by side a
knife-edged
ridge is
formed
between
the two
steep-sided
back walls
– this is
called an
arête
Arête
Mountain
Environments
What are mountain
landscapes like?
85*
Extreme
Environments
Mountain
Environments
What are mountain
landscapes like?
Third corrie – on other side of the mountain
If three corries are
found together a
horn-shaped
mountain is
formed from the
glacial erosion on
all sides – this is
called a
pyramidal peak.
Pyramidal peak
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Extreme
Environments
Mountain
Environments
What are mountain
landscapes like?
Glaciers come in different shapes and sizes – as well as corrie glaciers there are longer valley
glaciers which leave glacial troughs when the ice has gone (receded):
The valley glacier
erodes by abrasion
and plucking.
Moraine – material
transported and
deposited by the
glacier – can be
lateral, medial and
terminal.
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Extreme
Environments
Mountain
Environments
What are mountain
landscapes like?
Glaciers come in different shapes and sizes – after the ice melts we see the effect of the glaciers on
the landscape – here erosion by valley glaciers has left behind U-shaped valleys:
Ribbon lake – a long,
narrow body of water in a
deeply eroded glacial
valley. Some are trapped
behind glacial deposits
(terminal moraine).
Terminal moraine – where
the glacier ended it left
behind this pile of stones,
boulders and soil, which
made a ridge across the
valley.
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Extreme
Environments
Mountain
Environments
What are mountain
landscapes like?
Glaciers come in different shapes and sizes – after the ice melts we see the effect of the glaciers on
the landscape – here erosion by valley glaciers has left behind U-shaped valleys:
Glacial trough/U-shaped valley
– a deep, steep-sided, flatbottomed valley – usually very
straight.
Truncated spur – before
glaciation this was a ridge round
which a river valley curved.
Glaciation eroded away the end
of the ridge leaving an area of
high ground protruding into the
valley..
Hanging valley – was a small
tributary valley to the main river
valley before glaciation – the
main river valley eroded deeper
during glaciation , leaving this
smaller valley above the level of
the main valley– can be a
waterfall between the hanging
valley and the main valley.
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Extreme
Environments
Mountain
Environments
What are mountain
landscapes like?
Rivers also erode the landscape in mountain environments – these are known as fluvial
processes – they create certain landforms:
V-shaped valleys
A V-shaped valley – the
process begins with the river
eroding downwards (vertically)
due to:
• abrasion – sand and stones
wear away the bed and banks
of the river channel
• hydraulic action - the fastflowing water is forced into
cracks in the banks breaking
them up
• solution – water dissolves
soluble minerals from the bed
and banks
90
Extreme
Environments
Mountain
Environments
What are mountain
landscapes like?
Rivers also erode the landscape in mountain environments – these are known as fluvial
processes – they create certain landforms:
V-shaped valleys
1) The river erodes
downwards as
boulders, stones
and rock particles
are bounced and
scraped along the
channel bed.
2) As the river cuts
down, the steep
sides are attached
by weathering.
This breaks up and
loosens the soil and
rock.
3) The loosened
material slowly
creeps down the
slope because of
gravity or is washed
into the river by
rainwater.
4) The river carries
material away and
the end result is a
V-shaped valley.
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Extreme
Environments
Mountain
Environments
What are mountain
landscapes like?
Rivers also erode the landscape in mountain environments – these are known as fluvial
processes – they create certain landforms:
Interlocking spurs
The photograph shows how hills stick out like the
teeth of a zip in the river’s path – these are called
spurs.
The river doesn’t have the energy to erode the spurs,
so it winds its way around them – this creates the
landform of interlocking spurs.
IF THE V-SHAPED VALLEY IS FILLED WITH ICE (A
VALLEY GLACIER), IT WILL ERODE THE LANDSCAPE
CREATING A U-SHAPED VALLEY. THE INTERLOCKING
SPURS WILL BE WORN AWAY BY THE ICE LEAVING
TRUNCATED SPURS.
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Extreme
Environments
Mountain
Environments
What are mountain
landscapes like?
Rivers also transport and deposit material – these are also fluvial processes – they
create certain landforms:
Flood plains
• If a river flows on the floor of a Ushaped valley it can flood the land on
either side of the river channel – this is
the flood plain.
• When the river floods the material it has
carried (transported) is deposited in the
form of fine silt called alluvium – this
builds up the flood plain and makes the
land very fertile for crops.
flood plain
alluvium
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Extreme
Environments
Mountain
Environments
Tourism – Machu Picchu – an example of a
cultural/sight-seeing holiday
The mysterious lost city of the Incas, high in the
Andes – 70 km from the nearest city – Cuzco.
• Half a million people visit every year putting
pressure on the site and the surrounding
environment – 2000 a day (grows by 6% a year).
• Tourists get there by train (from Aguas Calientes)
or by hiking along the Inca Trail (6000 in 1984;
82000 in 2004).
• Aguas Calientes can only be reached by train –
there are plans to build a road (the town’s
population has already grown from 500 to 4000 in
10 years).
• Plans to build a cable car to the site from Aguas
Calientes.
IMPROVEMENTS TO ACCESSIBILITY WOULD
INCREASE THE VISITOR NUMBERS EVEN
MORE.
How do people use
mountain
environments?
94*
Extreme
Environments
Mountain
Environments
How do people use
mountain
environments?
Tourism in an LEDC – Machu Picchu – an example of a
cultural/sight-seeing holiday
There are social/economic (s) and environmental (e) costs and
benefits to tourism:
Tourism – costs – negative impacts
• site is being eroded by tourists feet (e)
• Inca trail – vegetation worn away by walking and timber cut for fuel
(e)
• tourism is an unreliable employer – unemployment in the low season
& poorly paid jobs (s)
• more sewage in Aguas Calientes pumped into river & increased litter
(e)
• money from tourism goes to other countries where the travel
companies are based (s)
• loss of traditional culture - people forced off their land to make way
for construction to aid tourism (s)
• poor working conditions (e.g. for porters) (s)
95*
Extreme
Environments
Mountain
Environments
How do people use
mountain
environments?
Tourism – Machu Picchu – an example of a cultural/sight-seeing holiday –
benefits/positive impacts
• creates jobs – formal (e.g. in a hotel/travel guides) & informal (not employed by anyone
– street vendors selling postcards) (s)
• entrance fees and taxes on tourism = extra money for the Government of Peru (s)
• new facilities for tourists benefit local people (e.g. new infrastructure – roads/bridges –
new bridge across the Vilcanota river to Machu Picchu will bring more tourists and can
also be used by farmers to get goods to market quicker than before improving the quality
of their life) (s)
THERE ISN’T A SINGLE ENVIRONMENTAL BENEFIT
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Extreme
Environments
Mountain
Environments
What are the
alternative futures
for the Andes?
There are positive impacts of tourism at Machu Picchu, but tourism at the site is currently
unsustainable:
Economically
sustainable?
(generates money for
people and future
developments)
Socially sustainable?
(meets peoples’ needs
so they can live
contented lives now and
in the future)
Environmentally
sustainable?
(protects the
environment from harm
and conserves
resources)
NO
NO
NO
e.g. Price of goods and services /property in local towns have
increased – too expensive for locals.
e.g. Some tourists behave badly and upset local people culture conflict – tourists dominate local facilities/services;
trekking harms indigenous farming environments – local
people often end up working in informal jobs in the tourist
industry where they are not respected (e.g. porters treated
poorly).
e.g. The natural environment is overused and changed by
tourism- Machu Picchu and Inca Trail being eroded by tourists
feet – vegetation cut down or worn away.
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Extreme
Environments
Mountain
Environments
What are the
alternative futures
for the Andes?
Tourism – Machu Picchu – an example of a cultural/sight-seeing holiday –
solutions:
Sustainable, eco-tourism – responsible travel to natural areas which
conserves the environment and sustains the well-being of the people:
•
•
•
•
•
offer fair wages
buying fresh local produce
minimising waste, leaving no litter
ensuring good working conditions (e.g. for porters)
trekking groups limited to 12
98*
Extreme
Environments
Mountain
Environments
What are the
alternative futures
for the Andes?
Tourism – Machu Picchu – an example of a sustainably managed holiday - eco-tourism :
HIGH INCA TRAIL TREK TO MACHU PICCHU
Economically
sustainable?
(generates money for
people and future
developments)
Socially sustainable?
(meets peoples’ needs
so they can live
contented lives now and
in the future)
Environmentally
sustainable?
(protects the
environment from harm
and conserves
resources)
YES
Porters, cooks and mule wranglers are formally employed –
local people are used and are paid a fair wage.
YES
Travel company are committed to staff welfare - camp staff
receive all accommodation, transport and food whilst on the
trek.
Travel company funded a centre to provide advice and
support to the local community on a range of social issues
YES
All waste is removed from campsites and
recycled/composted.
Walkers encouraged to stick to footpaths to cut down on
erosion
99*
Extreme
Environments
Mountain
Environments
How do people use
mountain
environments?
Indigenous people
The Aymara Indians live on the Altiplano – a sparsely populated plateau
formed from deposits brought down from the mountains by wind and water –
they make poor soils & most Aymara Indians are subsistence farmers
(growing enough food to survive) – struggling to make a living in a harsh
environment. The terrain makes it difficult to take food to markets to sell.
The Indians depend on two crops – potatoes and quinoa. Quinoa is a grain
crop with all the nutritional benefits needed for a healthy diet (seeds are cooked
like rice & leaves are boiled like spinach) – the stalks can also be burnt for fuel.
Quinoa grows well at high altitudes in poor soil with little rainfall, in both hot and
cold weather.
The Aymara also keep llamas and alpacas for meat and wool.
100*
Extreme
Environments
Mountain
Environments
What are the
alternative futures
for the Andes?
The future of farming in the Andes – sustainable or not?
Alpaca farming – large-scale ranching:
Countries such as China and Australia now have their own alpaca
herds – to protect the future of the industry in Peru large-scale
ranching is being developed with wealthier farmers taking over
smaller farms – many see this as more sustainable:
• farmers invest large amounts in pure alpacas with finer fibres that
make more money
• farmers have buildings insulated against the cold by mud – alpacas
can be moved indoors when it snows – alpacas survive the winter
months
• fibres go to a processing factory in Arequipa – textiles are
manufactured for export – using machinery to produce clothing for
China, USA, Australia and New Zealand large profits can be made.
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Extreme
Environments
Mountain
Environments
How do people use
mountain
environments?
Indigenous people – rural to urban migration
For years people from the Altiplano have been
migrating from the countryside to the city – rural to
urban migration:
Push factors
cold, dry climate; poor soils; few jobs other than
farming; poor educational opportunities; lack of
healthcare; poor diet and malnutrition (the renewed
popularity of quinoa is helping with this), lack of
clean water and electricity
Pull factors
more work; higher income (30 times higher than
farming); educational opportunities; housing;
healthcare and a higher life expectancy.
102*
Extreme
Environments
Mountain
Environments
What are the
alternative futures
for the Andes?
The future of farming in the Andes – sustainable or not?
Quinoa farming:
• quinoa is one of the planet’s most nutritious foods – a health food for people in
Europe, USA, China and Japan
• farmers can now sell their quinoa crop – prices have tripled since 2006 – the
crop has improved quality of life of people in some of the poorest regions of the
Andes
However, quinoa is worth more to the indigenous people as something to sell –
as a result they eat less of it themselves and their diets have become much
poorer as a result. People are returning home from towns and cities to grow
quinoa, but bitter disputes are breaking out about who owns the land on which
quinoa is grown.
Ethical consumers in MEDCs are not always aware that quinoa is now no
longer affordable to indigenous people in the Andes – it is better for indigenous
people to sell the crop and their traditional diet is suffering as a result.
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Extreme
Environments
Mountain
Environments
How do people use
mountain
environments?
Other uses of the Andes by people:
Scientists use the Andes:
• to develop commercial farming methods – e.g.
world renowned animal experts are researching
alpacas to make sure that the purest animals with
the finest wool can reproduce and maintain the
quality of the fibres in future generations
• to understand volcanic activity and develop the
potential of geothermal power
• to understand the impacts of climate change
through studying glacial retreat – understanding
the impacts on water supply in the Andes
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Extreme
Environments
Mountain
Environments
condensation
precipitation
evaporation
rivers carry
water back to
the ocean
How do people use
mountain
environments?
Mountains have a key role
in the hydrological cycle –
precipitation (rain, hail, sleet
or snow) levels are high in
mountain areas due to relief
rainfall – a mixture of
surface runoff (rainwater
running along the ground),
throughflow (rainwater
flowing downhill through
soil) and groundwater flow
(slow movement of water
downhill through rock
beneath the ground)
supplies water to major
rivers.
105*
Extreme
Environments
Mountain
Environments
How do people use
mountain
environments?
Mountains can provide valuable natural resources that can be exploited – the
Andes are a source of hydro-electric and geothermal power:
Hydro-electric power (HEP):
Running water is used to drive turbines. Certain physical conditions are needed – these conditions
are very common in the Andes with its deep valleys and rivers:
• fast flowing water – the Andes have very steep gradients increasing water speed – excellent for
HEP
• high rainfall all year & snow melt
• either a lake as a natural water store, or a narrow and deep valley with rocky sides to build a dam
and create a reservoir
Once the HEP is operating, there are many advantages making HEP a sustainable form of energy:
• continuous production - renewable energy
• no water or air pollution – no CO2 created
• low cost
• water can be used for other purposes when it reaches further downstream
Unfortunately, sites with good physical conditions are not found anywhere. If a dam needs to be
built to store enough water, this increases costs. Flooding the land behind the dam, drowns forests,
destroys wildlife habitats and forces people off their land.
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Extreme
Environments
Mountain
Environments
How do people use
mountain
environments?
Mountains can provide valuable natural resources that can be exploited – the
Andes are a source of hydro-electric and geothermal power:
Hydro-electric power (HEP):
Case study in the Andes – Peru gets 80% of its electricity from HEP.
The Yuncan Dam Project is located on the Puacartambo and Huachon rivers in north east Peru. It
cost $262m to build.
It produces 901GWh of electrical power per year with most of this electricity going to the national
grid in Peru. However, because hydro-electric power varies with rainfall amounts and snow melt, in
the last few years Peru has been reducing its dependence on HEP but using more and more
natural gas. As glaciers in the Andes melt due to climate change, Peru has lost water equivalent to
10 years supply to the capital city Lima.
107
Extreme
Environments
Mountain
Environments
What are the
alternative futures
for the Andes?
Mountains can provide valuable natural resources that can be exploited – the
Andes are a source of hydro-electric and geothermal power:
Hydro-electric power (HEP):
There are many remote villages in
the Andes with no electricity supply.
People are leaving such villages to
find work in nearby towns and cities
– rural to urban migration.
HEP has been used on a small
scale to provide electricity to
isolated communities – with
pipelines and small turbines
generating electricity 24 hours a
day, villages have been regenerated
with new businesses growing – less
people are now migrating away.
small-scale, sustainable use of HEP
108*
Extreme
Environments
Mountain
Environments
What are the
alternative futures
for the Andes?
Mountains can provide valuable natural resources that can be exploited – the
Andes are a source of hydro-electric and geothermal power:
Geothermal Power – another renewable form of energy that generates electricity
without burning fossil fuels and creating CO2:
The Andes also contain many volcanic areas - the volcanic rocks may heat water so
that it rises to the surface naturally as hot water and steam. Here the steam can be
used to drive turbines and generate electricity.
Unlike HEP, geothermal is not dependant on the weather but installation and start up
costs can be expensive and drilling down can sometime release harmful gases.
Currently the Andes has few geothermal power stations but plans are underway for this
type of energy to become more and more exploited.
109*
Extreme
Environments
Mountain
environments
What challenges do mountain
environments pose and how
can they be overcome?
Mountaineers use the Andes because they offer the opportunity for great achievements, climbing
spectacular and challenging mountains (e.g. Siula Grande at 6,344m).
Mountaineers face frostbite, injury and even death – less oxygen at high altitudes – muscles become
less efficient – must gain height slowly – 600m a day. Whilst there is plenty of snow and ice, water is in
short supply as is food. Other challenges for people include:
Transport and accessibility – very difficult due to steep slopes – roads and railways have to be
constructed around these – costly and difficult to build – often walking is the only option. Snow line in
Peru is at 4500m – snow and ice make travelling even harder. Storms can last days during which travel is
impossible.
Remoteness – because transport is so difficult people living in remote areas have little or no contact with
the world outside their village. Many places are a long way from specialist help – Aconcagua is 113km
from the nearest city – if an emergency happens often the only way out is by foot.
Shelter – in a storm shelter is needed quickly – local residents can use their houses, but mountaineers
will have to put up tent, dig a snow hole or find a place in the rocks.
Indigenous people – develop larger lungs and produce more blood cells to deal with lower air pressure
and lack of oxygen. They have adapted to survive – e.g. growing crops on steep sided valleys – can only
produce small amounts. It is however difficult to access education to get the skills needed for better jobs
and many live without a clean water supply and sewage disposal because the cost of providing this for
remote areas is too high and natural water is in short supply – dehydration is a problem at high altitudes.
110
Extreme
Environments
Mountain
Environments
What challenges do mountain
environments pose and how
can they be overcome?
Mountaineers manage the challenges in different ways:
Reflective
glasses –
protects eyes
from the glare
Multi-layered
clothing – trap
air – insulation
from the cold
Insulated
gloves –
protection from
frost bite
Equipment – lightweight
oxygen cylinder, ice axe
to climb steep ice &
altitude stoves to melt
ice for water supply
Windproof jacket –
duvet jackets filled with
feathers – warm and
light – keep body’s
core temperature
stable by avoiding cold
Spiked boots –
avoid slipping and
falling in difficult
terrain – snow and
ice.
111*
Extreme
Environments
Mountain
Environments
What challenges do
mountain
environments pose?
Natural hazards – the 10 highest volcanoes in the world
are found in the Andes – earthquakes are also frequent:
Earthquakes – 16th August 2007 – earthquake measuring
7.9 on the Richter scale hit Peru - 337 confirmed deaths.
Volcano – Ubinas – Peru – spewed acid-laden ash over
surrounding area – 640 families in 6 villages affected – eye
and breathing problems. Animals died from drinking
contaminated water & eating contaminated grass – these
animals had been a source of food and money – poverty
made worse.
112*
Extreme
Environments
Mountain
Environments
What challenges do
mountain
environments pose?
Natural hazards –
Landslides/landslips – 1998 – city of Santa Teresa destroyed – 15
people died – 2000 residents lost homes and livelihoods. Bridge over
the Vilcanota river connecting the city to Machu Picchu was destroyed –
now a 15 hour journey to Cuzco in order to transport goods
Avalanches – large amount of snow falling suddenly down a
mountainside – caused by:
• snowfall – usually within 24 hours of heavy snow (over 30cm)
• temperature – increases weaken upper layers of snow
• wind – uneven snow on leeward side dropped by wind
• ground cover – most avalanches caused by smooth ground
• slope – most on convex slopes between 30 and 45 degrees (where
most ski slopes are found)
113*
Extreme
Environments
Mountain
Environments
How can challenges
be overcome?
Managing natural hazards –
Volcanic eruptions –
• scientists monitor volcanoes and set up warning systems via radio, loudhailer
and sirens. People are then able to evacuate areas that are threatened by the
eruption.
Earthquakes –
• monitoring and warning systems – giving people time to take action (e.g.
allowing people to drop (often under a table), cover and hold on).
• buildings can be designed to withstand the shaking of the earth – although this
is difficult for LEDCs such as Peru where many of the buildings are poorly
constructed.
• education on emergency procedures (e.g. earthquake drills at schools).
114*
Extreme
Environments
Mountain
Environments
How can challenges
be overcome?
Managing natural hazards –
Landslides/landslips –
• landslide hazard analysis helps predict where landslides are likely to take place allowing
land use planning – deciding where it is safe to build.
• early predictions and warnings are essential for the reduction of property damage and
loss of life – data from different sources is mapped using GIS to allow accurate analysis
and make effective predictions.
Avalanches –
• explosives are used to prevent avalanches, by triggering smaller avalanches that break
down instabilities in snow.
• snow fences and light walls can be used to direct the placement of snow.
• trees can either be planted or they can be conserved, such as in the building of a ski
resort, to help prevent and reduce the strength of avalanches.
115*
Extreme
Environments
Mountain
Environments
What are the
alternative futures
for the Andes?
Climate change (increased CO2 and other greenhouse gases trapping heat) –
• Melting the ice and snow and causing glaciers to retreat (ice melts at the end of the
glacier faster than it accumulates in the mountain).
• In Peru (Cordillera Blanca range) glaciers terminate 800 metres higher up the mountain
than they did 60 years ago. Studies show that the top 20 metres of ice has melted and
new layers are not forming. Most of the lower altitude glaciers in Peru will disappear within
20 years.
116*
Extreme
Environments
Mountain
Environments
What are the
alternative futures
for the Andes?
Climate change –
Possible impacts in Peru (h – human; e – environmental):
• Glaciers supply water to Peru’s dry coastal region. No glaciers = no water for rivers = no water
supply for coastal cities which are growing rapidly. (h)
• Farmers depend on water – less snow as the snow line gets higher means less water – animals
have less food and their wool is no longer growing as well as it did. Farmers can’t plant potatoes in
lower fields due to lack of water – have to plant higher where there is thinner soil. (h)
• Chunks of melting ice falling from glaciers could trigger
devastating floods (e.g. city of Huarez is threatened). (h/e)
• Peru gets 80% of its electricity from hydro-electric power
(HEP) – is this runs out power stations may need to use fossil
fuels like coal. (h/e)
• Ecosystems affected as the snow line gets higher – mosquitoes,
normally found in low-lying areas have been found near glaciers – can spread the disease malaria
– many deaths as most can’t afford medicines. Wildlife/vegetation is threatened – habitats
destroyed as the snow line gets higher. (h/e)
117*
Extreme
Environments
Extreme
Environments
How have extreme
environments been
represented in cultural
resources?
Mountains have been represented in paintings
in the past and present – this allows the artist to
show how dramatic the landscape is and the
impact it has on people – the artist can use their
own imagination and skill to make sure the
painting shows how extreme the mountain
environment is:
These paintings show
the steep slopes and
jagged rocks found in
mountain areas – as
well as the storms and
snow that are also
common in these
environments – in each
case people are shown
responding with fear to
the environment.
118*
Extreme
Environments
Extreme
Environments
How have extreme
environments been
represented in cultural
resources?
The Sahara is so vast at 9 million
sq km, it takes a range of
photographs to identify the key
features:
• physical geography – the
natural landscape
• human geography – features
relating to people and places
• environmental geography –
the positive/negative impacts
people have on the natural
environment.
119*
Extreme
Environments
Extreme
Environments
How have extreme
environments been
represented in cultural
resources?
Extreme environments have also
attracted film makers – not only
do they provide dramatic
landscapes, because they are
places on the very edge of where
humans can survive, they provide
the opportunity to make exciting
films by showing people trying
to live through the most
challenging of life-threatening
circumstances.
Touching the Void is based on a book written by Joe Simpson – it is an example of
expedition literature – it tells the story of two mountaineers who set off to climb
Siula Grande in the Andes, encountering extreme and life-threatening situations.
Not only is it a gripping story of survival, it is also an excellent example of how
expedition literature can give us a real insight into what it is like to spend
time in environments on the very edge of where humans can survive.
120*
Extreme
Environments
Extreme
Environments
How have extreme
environments been
represented in cultural
resources?
“Having done its basic job of taking us through the pass and onto the escarpment, the
tarmac ends abruptly. The road reverts to dirt track but soon the rubble gives way to softer,
sandier terrain, and by the time we reach the outskirts of Chinguetti we are on the edge of a
sand sea, classic date-box desert, for which the Arab word erg sounds awfully inadequate.”
This is an extract from Michael Palin’s ‘Sahara’ – it is an example of travel writing. We can learn
a lot about deserts from books like this – not only are they written in a creative way that make them
more interesting to read than textbooks, they bring extreme environments to life with a focus on the
lives of people living and working in the desert – they also contain factual, place-specific facts and
figures.
The book was based on the BBC
documentary ‘Sahara’ – extreme
environments also attract programme
makers because of the dramatic
landscapes and the interesting lives that
people live there – trying to survive in
challenging circumstances. Watching 15
minutes of Kate Humble’s documentary
on the Andes is a great way of becoming
familiar with the location in preparation http://www.youtube.com/
for the exam!!
watch?v=-iY9BXcAKRg
121*
Extreme
Environments
Extreme
Environments
Spell of the Andes
‘This is a song of the Andes,
That reaches unto the sky on the slow
warm days,
When the Cholos play,
And the river runs low and high.
The towering Andes look down
In the passing sun: ‘I’m one with the
Andes
Brotherhood, I’m a dreamer, with a song’
I came from afar to see her
And how beautiful she really is, with her
strong hardness, fresh freedom O God!
How I want to breath her in the autumn
of my life!’
How have extreme
environments been
represented in cultural
resources?
Poems are often used to bring
extreme environments to life:
This poem is by Dennis L. Siluk.
Notice all the words that are used
to describe the Andes mountains
and how they bring the
environment to life in your
imagination – e.g. towering
Andes; that reaches unto the sky.
122*
Extreme
Environments
Extreme
Environments
For your sake, I hurry over
land and water,
For your sake, I cross the
desert and split the
mountain in two,
And turn my face from all
things
Until I reach the place
Where I am alone with You
Poem by Al Hallaj
People often represent
deserts as spiritual places
in poems – many people
have gone into extreme
environments to feel closer
to God.
How have extreme
environments been
represented in cultural
resources?
The artist has also shown the
Andes as a spiritual place in
this painting – an environment
that can only have been
created by God:
123*
Extreme
Environments
Extreme
Environments
How have extreme
environments been
represented in cultural
resources?
Specimen exam question:
Identify one source of information that you have found useful when
studying your extreme environment. Explain how it helped your
understanding of the extreme environment.
Things to consider in an answer:
• DVD/documentary had a lot of background information about how
people used the environment.
• Textbook gave me lots of facts and figures – it was up to date & gave
me the current picture of the environment.
• DVD/film had images that showed key features of the
climate/landscape & showed the challenges faced by people in the
environment.