Extreme Environments

What are hot deserts like? Physical features Barchan Dunes

Hot Deserts

Cross section

There are lots of different types of Sand Dune. They will differ according to the strength/direction of the wind, amount of vegetation, amount and type of sand. As the sand is loose, many types of sand dunes will migrate (move), due to the wind. Sand dunes mostly form when there is an obstacle – the sand builds around the obstacle – e.g. vegetation.

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Prevailing Wind

Sand deposited

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Extreme Environments

What are hot deserts like? Physical features Barchan Dunes

Hot Deserts

A Barchan Dune has a particular shape. It is a crescent shape with ‘horns’ pointing downwind. The upwind slope is approx 340 & the downwind slope is approx 150. Barchan dunes occur where there’s a limited supply of sand, thereforethey may by up to 100m apart. They form around an obstruction. The obstruction causes the wind to lose speed & then deposits, which causes a greater obstruction & more material is deposited. They will move over time

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Extreme Environments

How do people use hot deserts? Oil and Gas

Hot Deserts

General Beneath the Sahara are layers of sedimentary rock. Oil and gas is trapped beneath after is was formed from the remains of microscopic organisms millions of years ago.

Positives Exporting oil and gas can make a lot of money for countries.

Negatives The money isn’t distributed equally in the country & companies are often owned by overseas companies.

Oilfield drilling rig

It is very expensive to find oil and gas. Many of the larger, easy to find oil wells have now been used up. Transport oil and gas through pipelines is very expensive. Oil & gas are non-renewable resources – one day they’ll run out & burning these releases CO2.

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Tourism Many people find deserts to be fascinating and like the idea of visiting a desert. There are many tour companies that offer desert holidays, catering for different experiences – e.g. self drive, buggies, Bedouin tents/camel treks.

Extreme Environments

How do people use hot deserts?Tourism intro

Hot Deserts

Positives People are able to find out about different cultures. Some money from tourism will go to locals. Negatives Some areas may have delicate environments which could be damaged by tourism. Some tours companies are foreign owned, meaning that not all money goes to the locals.

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Extreme Environments

How do people use hot deserts?Tourism examples

Hot Deserts

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Extreme Environments

How do people use hot deserts?Tourism examples

Hot Deserts

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You need to know: examples of different activities.The scale of each activityThe impact upon the environments (+ or -)The impact upon different groups of people (+ or -)

Extreme Environments

How do people use hot deserts?Agriculture

Hot Deserts

In deserts, there is lots of flat, cheap land which makes it ideal for agriculture. Of course, water is needed for crops to grow. This can either come from irrigation channels which take water from rivers, or from well which takes water from under-ground aquifers (water holding rocks).

Positives – allows greater areas of desert to be used. Creates employment e.g Egyptian potato farming

Negatives – River levels affects, aquifers will run out of water. Lots of chemicals are needed to feed the plants, as desert sand/soil has v few nutrients.

Desert

Agriculture

Irrigation channel

Water pumped up from aquifer

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The Bedouin The Bedouin are pastoral (raise animals) nomads (they move around from place to place). They overcome problems in the following ways:Water – They plan routes from water source to another. Also, use other indicators such as lines of plants and insects to find hidden underground water.Transport – Bedouins traditionally use camels as transport as they are able to carry large loads.

Extreme Environments

How do people use Hot Deserts?

Hot Deserts

Lighting a fire

Clothing - They traditionally wear woollen, loose fitting clothes, from their animals. These insulate against the heat of the day & provide warmth at night. Covering their bodies means that the amount of sweating is reduced, therefore reducing dehydration.Shelter–They need to be able to carry their shelter with them & pack up quickly. Their tents are made from Goat hair cloth as it is warm & waterproof. They are long/narrow allowing breeze to blow

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Extreme Environments

How do people use Hot Deserts?

Hot Deserts

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The Bedouin are mostly located in the Arabian Peninsula. The largest group is in Saudi Arabia.

Extreme Environments

How do people use Hot Deserts?

Hot Deserts

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Their culture is under threat due to:

Country boundaries. Many countries such as Israel & Jordan have strict border controls which stop the Bedouin from travelling

Climate Change. A number of ‘dry years’ have meant that grazing lands have become barren

Political systems. Some countries do not recognise the Bedouin unless they are permanent residents

Tourism. Some Bedouin routes have been developed for tourists – creating a conflict

Clash of cultures. Increased global communication have meant that many Bedouin have chosen to live in cities meaning that traditions are not passed through the generations

DesertificationThis is the process by which land turns into desert. After a ‘dry period’ land will often recover. Desertification is when the land is so damaged that it can’t recover.

The damage can be caused by physical (Natural) processes, or by Human (due to people) processes

One of the areas at risk of desertification is the Sahel, in Africa. It is on the southern edge of the Sahara. It is an area where some farming occurs & is mainly grassland

Extreme Environments

What Challenges do hot deserts pose? Desertification 1

Hot Deserts

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Desertification - Physical Causes:Less Rainfall – Overall, there has been a reduction in the amount of rain for the Sahel over the last few yearsLess Reliable Rainfall – Also, the rain is less reliable – it may be many years before its rains properly in an areaHigher Temps–This increases the amount of moisture/water lots through evaporation & transpiration (water from plants)Desertification - Human Causes:Irrigation–water for growing crops is quickly evaporated, salt in the water is left on the ground=unsuitable for future farming Over grazing – Herds of animals eat lots of vegetation. Too many animals means that the vegetation cannot recoverOver farming – Soil can’t recover from lots of farming. It loses it nutrients and loss of vegetation means that it blows away.More people - Many people in the Sahel use firewood. More people means too much may be collected-plants cannot recover.

Extreme Environments

What Challenges do hot deserts pose? Desertification 2

Hot Deserts

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Desertification – Some possible solutions

Afforestation – replanting trees in areas where they’ve been cut down.

Reduce the amount of urbanisation is ‘fringe’ areas close to the edge of deserts.

Change farming techniques so that less water is extracted from the ground.

Reduce the amount of over cultivation to allow the ground to recover

Extreme Environments

What Challenges do hot deserts pose? Desertification 3

Hot Deserts

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Some of the other challenges that Hot Deserts Pose:

Drought – This is caused by lack of water of a long period of times causes drought - Crops may fail.

Famine – This is caused by drought. Large numbers of people are not able to access food/water.

Cultures – Over time, cultures change. The Bedouin for example, find it more and more difficult to maintain their traditional way of life. Many cultures have dies out. This is sometimes due to desertification, there are not enough resources to support the Bedouin.

Extreme Environments

What Challenges do hot deserts pose?

Hot Deserts

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