IB Geography Extreme Environments

Where are cold environments found and what are the common characteristics

• High latitudes and altitudes

• Polar environments at north and south poles

• Periglacial area before polar environment

• Also cold environments in high altitude, mountainous areas.

Where are desert and semi-arid environments found and what are the common characteristics

• Around the tropics

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

• Arid receive less than 250ml a day, and semi arid between 250 and 500 mm rainfall

What is continentality

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

Why is it difficult to develop and settle in cold and high altitude environments

• 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

Why is it difficult to develop and settle in desert and semi-arid environments

• Lack of water

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

• Deserts are at risk of flash floods.

What is the comfort zone

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

How do indigenous people cope with cold environments

• 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

How do indigenous people cope with desert and semi-arid

• 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.

How can farmers cope with water shortages in dry areas

• 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

What affects a glacial system

a glacial system is the balance between inputs and output storage

• accumulation > ablation = glacier advances (postive regime)

• accumulation < ablation = glacier retreats (negative regime)

• accumulation = ablation = is steady

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

wadis

Wadis left over from dried up rivers, they have been eroded through flash floods

• river channels steep sided and flat bottomed

What is plucking

A method of glacial erosion, found at the base of the glacier

• As a glacier moves through a valley, pressure is exerted on the sides and bottom of the valley

• This generates friction and heat, causing the edges of the glacier to melt a bit \

• This meltwater freezes around rocks and stones under the glacier

• As the glacier moves forward, it 'plucks' this ice, pulling the rock away 

once rock moved out, and apart of ice can be used for abrasion now

What is abrasion

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

How are cirques/corries formed

an amphyteatre shaped valley, scooped out by erosion

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

• Ice accumulates in the hollow

• ice moves through gravity, rotational slip, eroding the floor though plucking and abrasion

• Freeze-thaw, plucking and abrasion further erode the hollow into a rounded, steep-sided 'armchair' shape with a lip at the bottom end

How are aretes formed

An arête is a knife-edge ridge. It is formed when two corries run back to back. As each glacier erodes either side of the ridge, the edge becomes steeper and the ridge becomes narrower.

What is the different between glacial drift and till

and what is glacial deposits

deposits are dropped by retreating or stagnant glaciers

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

Till- Angular, unsorted glacial deposits

What are the characteristics of Till

• 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

What are erratics

a form of glacial deposition

random rocks of different sizes and types from the area where they are found, thsu the material can be used to trace back origin

What is moraine

Lines of loose rock

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

Lateral moraine is at the ridge or 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

What is freeze thaw weathering

Freeze-thaw occurs when water continually seeps into cracks, freezes and expands, eventually breaking the rock apart.

happens over a long time

What is frost heave

When ground ice forces soil or small stones to the surface, frost heave occurs

What is solifluction

flowing of soil.

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

creates solifluction lobes and terracettes, forcing soil to heave upwards towards surface

What is patterned ground and how is it formed

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

the result of frost heave, solliflcuction, and vegetation

What is a pingo

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

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

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

What is thermokarst

Wet hollows 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

What are the 3 types of permafrost

must be frozen in the ground for at least 2 years

Continuous, large, unbroken stretches of permafrost

discontinuous, mostly permafrost, with some small, unfrozen ground (talik)

sporadic, where small patches of frozen ground occur

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

What is salt crystallisation in hot arid environments

1. In areas with diurnal temperatures, salt expands in rock, outwards pressure and rock cracks.

2. when water evaporates, leaving behind salt crystals, as temp rises slat expands exerting pressure, and rock cracks

What is disintegration in hot arid environments

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

What are the 3 types of river in hot arid environments

Exotic- comes from a different climate zone

Endoreic- Flows to an inland basin

Ephemeral- seasonal

What is deflation as a mode of wind erosion in hot arid environments

The progressive removal of small material, leaving behind larger materials. Forms a stony desert. In some cases, defaltion may remove sand to form a deflation hollows

rocks too heavy to be transported are called ventifacts

What is abrasion as a mode of wind erosion in hot arid environments

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

if rocks are homogenous - wind smooths surface

if rocks are heterogenous, weakend by faults, forming natural rock pedestals as rock face is etched

How can agriculture in hot, arid areas become more sustainable

Using drought-tolerant crops/fodder for livestock

Reducing herd size to reduce pressure on vegetation

Using animal dung as fertiliser

Building small scale dams

Using efficient forms of irrigation, such as drip irrigation

What causes soil infertility in hot arid environments

• Low organic content due to limited biomass

• Being thin

• Lacking in clay

• Salinisation which reduces water uptake of plants

Why is mineral extraction in hot arid environments difficult

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

• Housing and basic utilities need to be provided

• Water shortages may require desalination

Why are periglacial areas or tundra areas fragile

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. soils are frequentlyw aterlogged, as low temp thsu low evaporation rates

5. Permafrost is disrupted by heat

What is desertification

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

What are the consequences of desertification

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

What are the strategies for preventing desertification

• 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.

• through water management, of drip irrigation, earth dams used in wet seasonto store water

• eduactaion about sustainable farming techniques, agroforesty and crop rotation

What are the environmental effects of climate change in extreme environments

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

What are some coping strategies for climate change in extreme environments

• 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

What are some advantages and disadvantages of climate change in extreme environments

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

how are pyramidal peaks formed

a three-sided, pointed mountain peak

A pyramidal peak is formed where three or more corries and arêtes meet. Glaciers erode backwards towards each other, carving out the rocks by plucking and abrasion. Freeze thaw weathers the top of the mountain, creating a sharply pointed peak.

natural causes of desertification

• Soil erosion leads to the loss of nutrients. Plants are unable to establish and grow

• Rainfall patterns have become less predictable, leading to drought and any vegetation dying due to lack of water

• Reduced vegetation means that nutrients are not added to the soil through the decomposition of dead organic matter

• Any rain that does fall is often in short, intense bursts, leading to increased surface run off and soil erosion

human causes for desertification

• Population growth puts increased pressure on the land as people raise more animals and grow more crops

• Deforestation removes shade for the soil and means there are no roots which bind the soil together. This increases soil erosion, whilst decreasing infiltration and interception

• Over-cultivation leads to all the nutrients being taken up by crops, leaving none for future vegetation to grow

• Overgrazing means the vegetation has all gone due to the numbers of animals or the land does not have chance to recover

case study of desertifcation in kenya

in Kenya

• Nomadic Masai farmers have been forced to use smaller and smaller areas of land for grazing. This results in overgrazing, which removes the vegetation. The soil no longer has protection from the wind and rain, which leads to soil erosion and desertification

• Population growth increases the demand for food and fuelwood. This leads to over-cultivation and deforestation, reducing the amount of nutrients returned to the soil.

• Exposes the soil to wind and rain This further increases soil erosion, leading to desertification

• In Kenya increasing temperatures and more irregular rainfall are natural causes of desertification. However, these could be the result of the enhanced greenhouse effect (human cause) leading to climate change

land degredation

Land degradation indirectly affects about 350 million people in the developing world

Land degradation occurs through changes in soil character, wind erosion, or water shortages (droughts), which leaves the land unproductive or lost

what is affroforestry

Tree planting, such as the Great Green Wall across the Sahel, helps to reverse desertification in several ways:

• The roots help to bind the soil together, reducing soil erosion

• The canopy offers shade, helping to prevent the soil from drying out and also reducing soil erosion from rainfall landing directly on the soil

• Falling leaves and branches replace nutrients in the soil

• The trees increase animal and insect activity, which helps improve soil quality

example of indigenous displacement Siberia

In northern Siberia, the Yamal Peninsula is a remote, windblown tundra region, with largest natural gas reserve.

The Indigenous Nenets are nomadic reindeer herders that have used the Yamal Peninsula for over 1 000 years. They graze reindeer in the north during the summer and migrate south for the winter Due to climate change and oil and gas exploration, the Nenets are under threat Russia intends to exploit the region, putting the future of nomadic herding at considerable risk

role of TNC’s

In places such as Sudan, Egypt, Mali, and Uzbekistan, there are financial pressures because big companies are willing to pay large sums of money to buy land to grow cotton to sell abroad

what is desalitantion

the process of removing salt from seawater to make it drinkable, through reverse osmosis or distillation. It is very expensive to build and maintain

example of sustainable housing

in New Mexico, Earth-ship homes, they are passive solar homes made from natural and recyclable materials that are designed to be 'off-the-grid' and consume no fossil fuels or energy.

they are natuarally insulated through walls made of thick mud bricks.

The homes are oddly shaped to maximise solar energy In winter, sun-facing windows provide heat, while in summer they are shaded.

case study sweden

Sweden is a heavy consumer of energy due to its development and cold climate, however, it has some of the lowest carbon emissions of any developed country.

Sweden has invested money into renewable energy sources like solar and wind power, more than half of its energy from clean sources such as wind, sun, and water 95% of these green energy sources come from hydroelectricity, but solar and wind power are becoming more important 

irrigation in hot arid environments

Irrigation is typically used to support natural rain fall, but a regular water supply is hard to come by in hot, arid areas

high temperatures and strong sunlight cause water to evaporate quickly, adding to water scarcity

salinisation

Salinisation is where intense evaporation at the soil's surface encourages soil moisture and minerals to rise 

This leaves the soil with a high pH value

When irrigation water is added to the land and allowed to evaporate, this increases the effect of salinisation

Increased soil salinity restricts most plant growth by reducing water uptake by plant roots Some crops are more salt-tolerant than others and are called halophytes 

• Palm dates and cotton are halophytic

land owenership

Land ownership disputes can arise between indigenous populations, government entities, and private companies. For areas that rely on farming as their main source of income, land ownership is important for families to succeed and survive

benefits in cold environments

• Valuable minerals are found in many cold environments, such as nickel, gold, iron ore and diamonds in northern Canada and coal, tin and uranium in Russia

• abaundance of gas and oil

• Wilderness and adventure tourism to extreme cold environments is a growing industry for countries and local communities

  • however, does increase polltuion and demand fro energy and resources

challenges in cold environments

• Building roads, railways and pipelines for water and electricity supplies is very difficult on frozen ground that is liable to melt

• Homes are raised on stilts to prevent their heat from melting the permafrost, which can cause the land to sink and subside)

• The rugged and mountainous terrain make these areas inaccessible for vehicles to deliver goods and materials for development and day-to-day living

resource nationalism

thee assertion of control by people and governments, for strategic and economic reasons, over natural resources located on their territory

opportunities in hot arid environments

energy:

• Solar energy in areas such as the Mojave, Desert

• Wind, including the Tarfaya complex in the Sahara Desert

• Coal mining, such as the Thar coalfield

Reserves of a range of minerals include copper, uranium, and coal in

large tourism, however can disturb local cultures, such as drinking, pressure on resources

challenges in hot arid environments

the lack of available water, also due to extreme temperatures reaching 50 degrees

The abundant stores of natural resources can lead to political tensions over contested land or borders

case study Thar desert

between Pakistan and India

opportunities:

• The construction of the Indira Gandhi canal allows irrigation

• Tourists are attracted to seeing the different species found in the deserts on desert safaris 

• extraction of minerlas such as limestone and phosporus

• The Jaisalmer Wind Park is the world's fourth-largest wind farm

Challenges

• hot temperatures of 50 degrees

• precipitation very low and high evaporation

• low road accessibility, and tarmac may melt due to temp

rotational slip

Ice advances in a circular motion called rotational slip, which hollows and deepens the landscape

glacial till

Any material carried or moved by the glacier

U shaped valley

Glacial troughs are steep-sided valleys with a flat floor 

They start as V-shaped river valleys but due to the size and weight of the glacial ice, it changes to a U shape as the glacier erodes the sides and bottom, making the valley deeper and wider

Hanging Valley

These are small tributary glaciers found 'hanging' above the main valley floor When melting occurs, there are waterfalls onto the valley floor

ribbon lake

As a glacier flows, it travels over hard and soft rock Softer rock is less resistant to erosion, so a glacier will carve a deeper trough over this type of rock When the glacier has melted, water collects in these deeper areas This creates a long, thin lake called a ribbon lake

Truncated spur

Truncated spurs are past interlocking spur edges of past river action that have been cut-off forming cliff-like edges on the valley side

Found between hanging valleys and are an inverted 'V' shape  formed when the lower valley glacier cuts off previous ridges or spurs as it passes by

drumlins

Drumlins are elongated, egg-shaped hills made of glacial till

they are deposited as a result of friction between the ice and the underlying geology, causing the glacier to drop it’s deposits. as the glacier continues to advance the shape os formed, lee side is direction of ice

what is the difference between periglacial and glacial environment

altered by ice

• periglacial; within the ground

• glacial; above the ground

landforms are created through

• periglacial: freeze-thaw weathering and mass movement

• erosion and deposition

found

• periglacial:outer margins of cold environments

• glacial: high altitudes and latitudes

thaw lakes

meltwater cannot drain through the impermeable permafrost below and sits on the surface as thaw lakes

Thaw lakes are common in these poorly drained areas and as the water continues to absorb solar radiation, so the depth and size of these lakes increase in size

pressure exfoliation

This is where overburden is removed through weathering and erosion and the rock beneath is gradually exposed

The removal of the weight of the overburden releases the pressure on the rock beneath and the outer layer splits/fractures apart

Once fractures develop, water enters and chemical weathering takes place, leading to the formation of new low-density minerals

wind transportation 3 types

• Creep occurs when sand grains slide and roll across the surface

• Saltation occurs when the wind is strong enough to bounce particles close to the ground

  • Material moved by saltation may move around and push bigger particles that are too heavy to lift. They do not travel too far because tehy are heavy

• Suspension occurs when high-speed winds carry small dust particles (fine silt and clay) into the atmosphere

  • main cause of dust storms

water action in hot arid environments

Rainfall is sporadic:

• from flash floods, although short-lived, huge amounts of sediment are washed down from the mountains and deposited on alluvial lowland plains 

• Rain is able to hit the surface hard, moving small particles around and covering soil pores, which slows the rate of infiltration even further

sheetwash processes

Sheetwash erosion is a form of surface runoff critical in the transportation of soil sediments. This thin layer of water flows over the ground surface, rather than a distinct chanel

• The flow possesses enough force to detach soil particles and transport them.

• Sheetwash can move finer particles, including silt and clay, over considerable distances, depending on the flow's intensity.

yardangs

created through wind erosion

• looks like an upturned boat

• the softer rock strata is removed , leaving more resistant rock layer

• long ridges where the strata is vertical

zeugens

formed through wind erosion

• Zeugens form in the same way as yardangs, but the layers of resistant and less resistant rock lie horizontally 

• mushroom shaped

pedestal rocks

Thought to be the final remains of a zeugen, they are again primarily formed as a result of abrasion

It can also be found in areas where isolated rock peaks are exposed to the surface

Winds carrying fine sand particles act as an abrasive and start cutting and polishing the exposed rock 

Continued erosion leads to the eventual collapse of the pedestal

sand dunes

• They are the consequence of saltation

  • hte transport of hard particles over an uneven surface in a turbulent flow of air or water.

• Dunes grow as sand particles move up the gentle, windward slope, by the processes of saltation and surface creep

• The sand particles continually fall over the crest of the dune, onto the steeper, slightly concaved, leeward slope/slip face

• The top of the slip face is steep because it is made of fine-grained sand and it is kept steep by wind eddies

• The bottom of the slip face is gentle, contains coarse-grained sand and may have further sand ripples

canyons

• Canyons are deep gorges that usually have a river running through them

• Canyons are formed over millions of years when water rushes through any kind of rock, but especially sandstone and limestone

formed through DUDE

• D: deposition of sediment from rivers builds up layers of sedimentary rock

• U: uplift, the newly formed rock layers undergo uplift, where they rise up and form large plateaus

• D: downcutting, hydraulic action deepens the channel of a stream or valley by removing material from the stream's bed or the valley's floor

• E: erosion (not wind), erosion wears away at the sides of the plateaus and forms steeper gradients

rain shadow effect

A rain shadow is a patch of land that has been forced to become a desert because mountain ranges blocked all plant-growing, rainy weather. On one side of the mountain, wet weather systems drop rain and snow (windward side). On the other side of the mountain—the rain shadow side—all that precipitation is blocked (leeward side)

whata re factors effecting glacial abrasion

• ice thickness, more thick greater pressure, more effective abrasion

• hardness of bedrock, harder = better

• sliding of ice, the faster the better

frost creep

it is a type of solifluction, occurs because of frost heaving and thawing.

• the freezing of the surface lifts particles up at right angles to slope,

• as ice thaws the particles drop in elevation with the surface

• some partciles move slightly downslope due to gravity

Alluvial fan

cones of sediment deposited by rivers

different types of river flow in desserts

Exotic/ exogenous

• the source is another wetter environment, nile

Endorheic

• rivers that drain into an inland lake or sea

Ephemeral

• rivers that flow seasonally or after storms

butte

isolated peak, remnant of mesa or plateau, water has eroded most of rock

Mesa

quite large plateau with steep sides, isolated from plateau due to erosion or slope retreat

salt pans, playas

sites of formal or occasional lakes

oasis

formed when the water-bearing rocks are exposed at the surface, done by deflation

barchan or crescent dunes

sand dunes formed when wind speed is high and constant and limited supply of sand

they are u shaped

pediment

shallow slopes formed at the base of a cliff or a steep hill

arroys

channels that ave been enlarged by repeating floods

ANWR

Artcitic National Wildlife Refuge,

largest protected wildlife area in USA, 9 million hectares in north east Alaska

oil companies want to drill for oil

Greenland case study

in 2014, at the cusp of resource boom due to melting ice, discovering traces of oil underneath their ice.

many companies wanted to take over, but harsh waters and isolated living. Further the oil collapse in 2014, restricted countries development, still dependent on Denmark