Extreme Environments
Syllabus
1. Challenging environments
• Global distribution of extreme environments. Explain the global distribution of each of the two kinds
of extreme environment.
Describe the relief and climatic characteristics that make these environments extreme. Explain how
these characteristics present challenges for resource development and human habitation.
4 hours
• Population Explain the other factors responsible for a low density of population in these areas: human
discomfort, inaccessibility, remoteness.
Identify ways in which people adapt their activities to extremes of weather and climate.
2 hours
Lesson 1
On a blank copy of a world map try to identify as accurately as you can as many extreme environments.
(no atlases allowed). Work in pairs – prize for the best map
You need to consider.
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What is an extreme environment?
Where are they? Try to include place names if you can
Discussion: what is extreme?
What Makes an Extreme Environment?
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Hard to survive in
Very different at different times of year / day eg Sahara temp extremes
Lack of water
Difficult weather or difficult geographical situation – inaccessible?
Limited biodiversity
Sparsely populated
See http://koeppen-geiger.vu-wien.ac.at/pdf/kottek_et_al_2006_A4.pdf for climate map
Handout syllabus
Handout hazards in polar & high latitude regions (p117 Physical Environments)
Discuss adiabatic lapse rate (0.4 degrees per 100m wet – 1 degree every 100m dry. Average 0.6 degrees
per 100m)
Coldest temp ever recorded -89° C at Vostok scientific base in Antarctica.
Population of Antarctica is 0 (scientists during the summer)
(Who owns Antarctica? Discuss if time)
Polar Regions
1)
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Give 3 reasons why the poles are cold
Angle at which sun’s rays hit
Amount of atmosphere sun’s rays have to pass through
Albedo (ice has a v high albedo – lots of reflection)
Hand out student copy of High Altitude Regions
High Altitude Regions
There is the same temperature change between the equator and the poles as there is from 0m ASL to
9000m ASL
Nepal
Nepal is one of the most mountainous countries in the world.
The following map shows population distribution in Nepal. Use the map to write a detailed description
of Nepal’s population distribution. You should use place names as well as distance and direction in your
description
http://www.bestcountryreports.com/zoomify.asp?name=Z_Nepal_Pop
Eg Pop dist high in South, low in
North. (esp NW)
Pop is as low as 0 per km in parts of
NW including around Bagarchhap
Exceptions Kathmandu the capital has
a high popn density of 1000 people
per km
You should have noticed that there is a very clear negative correlation between population distribution
and altitude in Nepal. With the help of the map of Nepal (p84 Atlas) and p274 (PG), Identify the three
main regions found there and describe and explain their different characteristics.
Use the information you find to explain Nepal’s population distribution
1. Terai
Southern region, forming border with India. Long belt of alluvial plains (nutrient rich – good
farmland) which are able to support the high pop density of 1000 people per km. The altitude is
between 60m – 300m so is ideal for people to live and work. Flat land makes communication
and resource exploitation easier – hence highest popn density.
Biratnager 72m has a temp range of 10 -22 degrees in Jan and 26-32 degrees in July
2. Hilly Region
Stretches across the middle of Nepal ranges from 1525m to 3660m so high altitude means pop
density is lower than Terai (25 – 250 people per sq km) However, important rivers (ie a water
supply) and valleys mean that pop is higher here than may otherwise be expected in similar
terrain. Includes the capital Kathmandu.
Kathmandu (1336m) has a temp range of 2-18 degrees in Jan and 20 – 28 degrees in July
3. Himalayas
Highest Zone 3660- 8848 m (Everest) 17 peaks higher than 8000m = The Death Zone hence no
human habitation and pop density of 0. Also 240 snow peaks above 6000m so too extreme for
human habitation. Some limited habitation and small settlement on lower slopes.
Jiri (2003m) has a temp range of -3 – 13 degrees in January and 18-24 degrees in July
Above 5000m is below 0 year round.
Question Block 7A p274
7A qu1 explain the distribution of mountain ranges & glaciers shown in fig 7.1
Qu 2 Plot temp data from Switzerland & Nepal on 1 graph. Describe & explain the pattern shown.
Question Block 7B p274
7B plot air pressure & altitude data on one graph and altitude temperature data on another
Qu 2 Is rainfall more likely in areas of high air pressure or low air pressure? Use this information to
predict on which parts of mountains (top or bottom) rain is more likely to fall.
What Makes Glacial Environments Extreme?
Make notes on the following:
1. Climate & Relief
Cold – see graphs of Switzerland & Nepal. Winter temps below 0 eg Jiri in Nepal, January
low -3 degrees
Steep, rocky terrain, inaccessible.
Geologically young fold mountains have steep gradient and weak rock structures. Loose
structures and weathering means that many upland areas are unstable and at risk from
falling rocks and mass movement. High diurnal temp ranges mean that freeze thaw
weathering is prevalent, with the associated risk of rockfalls.
Risk of avalanche in snow covered areas
2. Effect of aspect – see p 276
Aspect = the direction a slope faces (ie how much sun it receives)
South facing slopes receive more sunlight and so more crops can be grown than on n
facing slopes. Settlements also tend to be on S facing slopes. This effect is more
pronounced in winter when the sun is low in the sky so N facing slopes are often in
complete shade. = more glaciers on N facing slopes (in N hemisphere)
Read p 276 and add any additional notes
3. Altitude & the biosphere p277 – difficulties of farming at altitude
Aspect affects farming, but so does altitude. Certain crops are unable to grow above a
certain altitude when it becomes too cold for them. (see diag 7.8 on p 278) eg broadleaf
forest grows up to 2500m on the S slope of Everest, but above that it gets too cold.
4. Risk of tectonic hazards p 277-8
Fold mountains eg Himalayas and The Alps are tectonically active. Risk of earthquakes
can deter people from living in a region and makes engineering more difficult. Wealthier
countries eg Switzerland are able to overcome this to a certain extent by building
earthquakes proof structures. This can prove more difficult in countries which cannot
afford to do so (Eg Nepal)
Explain how factors 1-4 present challenges for resource development and human habitation
Atmospheric and lithospheric hazards make human habitation more challenging. (give egs) The
steep terrain also limits accessibility, which makes extreme environments more remote.
Overcoming obstacles & adapting activities
Tourism : Ski resorts eg Chamonix French Alps – skiing in winter, hiking in summer. Cable cars
and chair lifts improve accessibility
Use http://www.highaltitudelife.com/ to identify some of the key challenges for human habitation of
living at high altitudes. Explain how people are able to overcome these challenges. Use case studies
wherever possible.
Difficulties of Human Habitation. As altitude increases there are decreases in air density, water
vapour, CO2 and impurities. Boiling point decreses to 72 degrees at the summit of Everest –
difficulties for cooking. Sunburn is much more likely due to increase in intensity of UV radiation.
Dehydration, dry skin etc caused by lack of moisture.
Hand out Yakutsk & ageing article
Yakutsk: Journey to the coldest city on earth http://www.independent.co.uk/travel/europe/yakutskjourney-to-the-coldest-city-on-earth-771503.html
Altitude speeds up ageing http://news.bbc.co.uk/2/hi/health/1940046.stm
Glaciation
Glacial Environment
Explain the advance and retreat of glaciers and the main features resulting from the processes
of erosion and deposition by glaciers.
See past temperature change
Reminder of GCSE work
Hwk dig out GCSE notes or look at BBC Bitesize website.
See http://www.uky.edu/AS/Geology/howell/goodies/elearning/module13swf.swf for
animation of different glaciers.
Watch DVD Extreme Ice 5.30-6.30 mins (Timelapse cameras showing changes) To show advance
and retreat of glaciers. See http://www.extremeicesurvey.org/index.php/galleries/ for pictures
(6.30-7mins role of ice sheets in affecting popn distribution – link to last lesson)
Explain past global patterns
See http://www.guardian.co.uk/environment/2007/jan/14/glaciers.travelandtransport
For problems created by glacial retreat
8-15.30 mins Extreme Ice DVD. Role of global warming in glaciers & glacier retreat – tracking
flows of Columbia glacier.
Handout glacier form & flow
Key terms Mass Balance, Ablation, Accumulation
http://phet.colorado.edu/simulations/sims.php?sim=Glaciers good animation to show flow and
deformation.
Features of glacial erosion & deposition – students who did IGCSE have done this last year
Test prior knowledge with glaciation dominoes. (Fast finishers can try to categorise different
landforms)
Key Terms, Corrie, Arete, pyramidal peak, hanging valley, U shaped valley, truncated spur,
drumlins, outwash plains, rouch moutenee. etc
Make notes on processes of erosion. Plucking, abrasion, rotational slip, freeze thaw weathering.
Make notes on key erosional features & look at Snowdonia case study See handout from
Waugh p110-115
Make notes on deposition and key depositional features. See handout from Waugh p116-120
Vid 20 mins Landforms Ice
If time – do triplets worksheet. Match each feature to its description. (NB there are two
descriptions for some and three for others, see answer sheet)
Exam qu 20 marks 40 mins
Usually short answer qu at first then a 6 mark qu then a 10 mark qu. (2mins a mark)
USE maps and figs from mapskills book.
Glaciation Test
Use examples and diagrams to help
1. What is the mass balance of a glacier (2 marks)
2. Using figure 1 (map extract of Cairngorm Mountains taken from p54 Essential Mapskills), give
the 6 figure grid ref of a tarn (1 mark)
3. When was the last glacial maximum? (1 mark)
4. Using figure 2 (photo taken from p55 Essential Mapskills) explain how glacial processes led to
the formation of features X, Y & Z (6 marks)
5. Explain the role of deposition in the formation of glacial features (10 marks)
OR
6.
Glacial deposition has a more significant impact on the landscape than glacial erosion. Discuss.
(10 marks)
Test Mark Scheme
1. What is the mass balance of a glacier (2 marks)
Mass balance = accumulation – ablation (1 mark) further explanation (1 mark)
2. Using figure 1 (map extract of cairngorm mountains taken from p54 Essential Mapwork Skills),
give the 6 figure grid ref of a tarn (1 mark)
960980 (or near) 943005 (or near) 982029 (others possible? ½ mark?)
3. When was the last glacial maximum? (1 mark)
15000 - 20000 years ago
4. Using figure 2 explain how glacial processes led to the formation of features X, Y & Z (6 marks)
X = Corrie, Y = arête / pyramidal peak, Z = tarn (1 mark if at least 2 correct)
For full marks must refer to different types of erosion; plucking, abrasion, rotational slip, freeze
thaw. Time.
5. Explain the role of deposition in the formation of glacial features (10 marks)
Answers should discuss both glacial deposits and fluvio glacial deposits and should explain the
difference between them and give egs of associated features.
Answers should make reference to the process of deposition – ie ice melt or velocity of
meltwater. Clear reference to different depositional features should be made. Where features
are a combination of erosion and deposition, (eg push moraine, drumlins, roche moutenee) this
should be referred to.
Reference to moraine should refer to different types of moraine.
There could be some overview and reference to the landscape on a larger scale
Periglaciation
Syllabus Ref: Periglacial environment Explain permafrost, patterned ground, solifluction, thermokarst,
pingos. (3 hours)
Intro to periglacial environments: See Climate classification map
Periglaciation is a term which refers to environments on the edge of ice sheets. Today the most
extensive periglacial environments lie in the arctic regions of Canada, The USA and Russia. These areas,
which have a tundra climate, soils and vegetation exhibit their own characteristic landforms.
What is periglaciation?
http://www.guardian.co.uk/environment/2009/oct/20/arctic-tundra article about melting permafrost in
Siberia
Use Chapter 5 of Waugh & Chapter 8 from Landform Systems to make notes on
Permafrost p159 LS
Currently, around 1/5 of the world’s land is underlain by permafrost. Most of this is in the Northern
hemisphere. The thickness of the permafrost layer varies, according to the type of permafrost. This is
regulated by the average annual temperature.
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Continuous Permafrost;
Temperatures very low in winter, summer very short.
Annual average temp >-5°C.
Can be up to 600m thick.
· Discontinuous Permafrost;
Þ Annual average temperature approx. between -5 and -1.5°C
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Sporadic Permafrost;
Annual temperature between -1.5 - 0°C.
found in small isolated patches, where local climate is relatively cold for the latitude.
Extends further due to effect of continent.
Active Layer
Solifluction (p167 LS)
http://www.fettes.com/Cairngorms/images/solifluction_siberia.jpg
Copy diag 8.21 from p 167 Landform Systems
Frost heave = gradual downslope movement of particles through the operation of each freeze thaw
cycle
Solifluction = downslope creep caused as the active layer thaws during the summer. Movement
decreases rapidly with depth and generally ceases by 2m below surface.
Rates of movement are related to the angle of slope, the amount of surface snow melt and
infiltration, the ice content of the active layer and veg cover.
The unsorted footslope deposits are known as head and may occur as sheets, benches or lobes.
Patterned Ground p164 LS
Repeated freeze thaw cycles gradually rearrange soil – surface sediments into a variety of patterned
shapes; stripes, lobes and polygons. A range of different sized sediments in the active layer are sorted
by the process of freeze thaw. The type of patterning is influenced by the thickness of the active
layer, the particle dimensions and the slope angle.
See fig 8.15 on p164 LS & fig 8.13 p 163 LS
Thermokarst (p166 LS)
http://images.google.com.hk/imgres?imgurl=http://ougseurope.org/rockon/surface/img/thermok
arst.jpg&imgrefurl=http://ougseurope.org/rockon/surface/thermokarst.asp&usg=__-gqnTHvA0Z2KxeuARbU58Ca0DU=&h=338&w=500&sz=33&hl=en&start=1&um=1&tbnid=7TqIqQUe06NQM:&tbnh=88&tbnw=130&prev=/images%3Fq%3Dthermokarst%26hl%3Den%26client%
3Dfirefox-a%26rls%3Dorg.mozilla:en-US:official%26sa%3DG%26um%3D1
The most widespread result of thawing ice-rich discontinuous permafrost is irregular ground
subsidence. This uneven land surface, pitted with depressions is called thermokarst.
Key feature is the presence of lots of pools and lakes.
Pingos
Pingos are large mounds with perennial ice cores. They are roughly circular 30 -600m in diameter
and 3 – 70 m high.
Open system pingos are where there is thin or discontinuous permafrost. Water can infiltrate and
refreeze, the pingo grows up from the bottom.
Closed system pingos are where continuous permafrost is found. They often form on the site of
small lakes where water becomes trapped and freezes.
Collapsed Pingo http://www.arctic.uoguelph.ca/cpe/environments/land/landforms/pingo.jpg
http://content.answers.com/main/content/img/oxford/Oxford_Geography/0198606737.pingo.2.jpg
See pingo pic for formation of open & closed system pingos from
http://science.jrank.org/pages/46464/pingo.html
Difference between aggradational landforms and degradational landforms
Aggradational = regular freeze thaw, expansion – contraction, eg patterned ground, pingos
Degradational = contraction & shrinkage eg thermokarst