IB Geography Extreme Environments

• High latitudes and altitudes

• Polar environments at north and south poles

• Periglacial area before polar environment

• Also cold environments in high altitude, mountainous areas.

• Around the tropics

• Stable low pressure conditions and large distance from the sea needed for these areas to form

• Also proximity to cold, upwelling currents to limit moisture in the air

The distance of land from the sea. Deserts require a high continentality

• Mountains are steep, so difficult to build on

• This also limits transport

• They also usually have thin, infertile soils which experience high levels or erosion

• Periglacial areas usually have waterlogged soils and low levels of evaporation

• Also a short growing season due to temperatures being high enough for only a small proportion of the year

• Lack of water

• Therefore, as well as high temperatures, agriculture is made difficult

• Deserts are at risk of flash floods.

The temperature and humidity range for human habitation. Although may be culturally bias as some indigenous populations are better able to deal with the cold than some other populations

• Migratory patterns(moving north during the summer and south in the winter to avoid extreme cold)

• The use of fishing in lakes and the sea for food as agriculture and livestock is difficult

• In the middle of the day they take a rest and avoid direct sunlight

• They travel in early morning and late night

• They wear lose fitting, thin garments to reduce sweating and overheating.

• Reducing the size of herds

• Exchange of livestock and products to suit drier conditions

• Greater use of drought-tolerant species

• Use of wild species and crops

• Windbreaks to reduce wind erosion of bare soil

• Herd diversification

Inputs - Accumulation of snow, avalanches, debris and meltwater

Outputs- Ablation, sublimation of ice to vapour and sublimation of ice

If accumulation is greater than ablation, glacier advances

If ablation is greater than accumulation, glacier retreats

If they are equal, the glacier is steady

Pollen from oaks and cedars, and small crocodiles found in the mountains

Ancient civilisations leaving cave paintings

Wadis left over from dried up rivers

A method of glacial erosion

• Occurs at the base or the glacier, and sometimes at the sides

• It is most effective in weakened rocks by joints/weathering

• As ice moves, meltwater seeps into the joints, freezes onto the rock, and then is ripped out by the moving glacier

A method of glacial erosion

• Debris carried by the glacier scrapes and scratches rock, leaving striations

• The amount/rate of erosion depends on, local geology, velocity of the glacier, weight and thickness of the ice, and the amount of load carried

• A pre-glacial hollow is enlarged by freeze-thaw and removal of snow melt

• Ice accumulates in the hollow

• After a critical weight and depth, the ice moves out in a rotational manner, and erodes the floor by plucking and abrasion

• Meltwater trickling down allows the cirque to grow by freeze-thaw.

• This leaves an armchair shaped hollow, which is usually filled with a lake

The recession (cutting back) of 2+ cirques.

From a pre glacial valley

They have steep sides and flat floors, and the interlocking spurs from the pre-glacial valley have been shortened

Tributary glaciers which do not cut down to the level of the main valley, but are left suspended above. They usually have a waterfall

Drift- glacial and meltwater deposits left after the ice has melted

Till- Angular, unsorted glacial deposits

• Poor sorting- it contains a large range of rock sizes

• Poor stratification- No regular sorting by size

• Mixture of rick types

• Many particles have striations

Large boulders, foreign to the local geology

Lines of loose rock

At the snout of the glacier there is a crescent shaped mound called terminal moraine

Lateral moraine is a ride of material found on the edge of a glacier

Where two glaciers merge and the two lateral moraines flow in the middle of the enlarged glacier, it is medial moraine

A process in which water freezes at 0 degrees and expands by 10%. It puts great pressure on jointed rocks. The more freeze thaw cycles a year, the greater the impact.

Where water which freezes in soil lifts individual particles of soil towards the surface. The stones in turn protect the ice from melting initially, so when the ice under stones finally melts, other particles have fallen back to their original levels, and the stones do not fall back as much

In winter water freezes in the soil causing expansion of the soil and segregation of individual soil particles. In spring the ice melts and water flows downhill. It cannot infiltrate the soil because of the impermeable permafrost. As it moves over the permafrost the soil becomes separated and are spread downslope

A general term describing the stone circles, polygons and stripes which are found in soils which are subjected to intense frost action.

Their exact mode of formation is unclear however frost heave, solifluction and vegetation are all believed to be mostly responsible

An isolated, conical hill which is found in periglacial environments. They are formed by the movement and freezing of water under pressure.

Open system- Formed when the source of water is from a distant, elevated source.

Closed system- Formed when the water is local, and the pingo is formed due to the expansion of permafrost

Depressions caused by subsidence due to the melting of permafrost. This can be due to

• cyclic changes in vegetation which may affect albedo

• Shifting of stream channels which may affect the amount of heat affecting permafrost

• Fire

Continuous, discontinuous and sporadic

The active layer of permafrost is found at the surface and it thaws out seasonally

Causes the breakdown of rock by solutions of salt. When water on rock evaporates, salt is left behind. As temperatures rise, salts expand and exert pressure on the rock

Found where there is a large diurnal temperature range. Rocks heat up during the day, and contract at night. This causes exfoliation of the outer layers of the rock, moisture is essential for this process.

Exotic- comes from a different climate zone

Endoreic- Flows to an inland basin

Ephemeral- seasonal

The progressive removal of small material, leaving behind larger materials. Forms a stony desert

Erosion carried out by wind borne particles. They act like sandpaper, smoothing surfaces.

Using drought-tolerant crops/fodder for livestock

Reducing herd size to reduce pressure on vegetation

Using animal dung as fertiliser

Building small scale dams

• Low organic content due to limited biomass

• Being thin

• Lacking in clay

• Salinisation which reduces water uptake of plants

• Most areas are very remote so transport is difficult and expensive

• Housing and basic utilities need to be provided

• Water shortages may require desalination

1. The ecosystem is highly susceptible to human impact due to the limited species involved

2. The very low temperatures reduce decomposition

3. Pollution has a very long lasting effect

4. Permafrost is disrupted by heat

The spread of desert like conditions into previously productive areas. Can be caused by overgrazing and deforestation

Environmental

• Loss of soil nutrients through wind and water erosion

• Changes in composition of vegetation and loss of biodiversity as vegetation is removed

• Reduction in land available for crop growth

Economic

• Reduced income from pastoralism and food crops

• Decreased availability of firewood, necessitating the purchase of oil

• Increased rural poverty

Social and cultural

• Loss of traditional knowledge and skills

• Forced migration due to food scarcity

• Social tensions in reception areas for migrants

• Reducing overgrazing by improving stock quality using vaccination, and better yield varieties

• Overgrazing can also be managed by better management and reduced herd sizes

• Reducing over cultivation can be achieved by using higher yield varieties, fertilisers, and irrigation.

• Finally reducing deforestation is done by social foresting, alternative fuels instead of using firewood, and agroforestry (where farmers continue cropping but use trees to provide shade and fertilise the soil.

Falling crop yields and rising food insecurity, increased water stress, flooding of low lying areas. Spread of diseases eg. Malaria

Conflict over resources eg. water and pasture. Loss of territory and border disputes, forced migration causing urban overcrowding. Tension over energy supplies

• Improving soil fertility by the careful use of fertilisers

• Using indigenous plant species

• Improving efficiency of irrigation systems and pest control

• Adopting water and soil conservation techniques using stone rows to reduce run-off on slopes

Disadvantages

• Unpredictable sea ice provides issues for Inuits

• More shipping mining and oil and gas exploration may threaten the environment

Advantages

• Farming may become more productive as the growing season will extend

• Forestry in some areas may become possible

• Tourism in cold environments may become more popular