hot deserts

Question 1

what is a hot desert?

Answer 1

arid areas receiving less than 250 mm rain per year

Question 2

where are hot deserts found

Answer 2

mostly in a belt between the tropics (30 north and south), with very little along the equator

Question 3

how do hot deserts form

Answer 3

• sun heats ground at equator
• warm, moist air rises, leaving low air pressure
• air cools and condenses, forming clouds
• convectional rain occurs (trf formation)
• air moves north and south at high altitude
• dry air sinks near tropics, high pressure
• falling dry air warms and travels back to equator via trade winds, creating hot, dry conditions

Question 4

why are deserts so hot?

Answer 4

sun relatively overhead in the tropics, energy is more intense as there is a smaller area and atmosphere to be heated.
little to no clouds also means there is no protection from sun in the day and no heat is retained in the night.

Question 5

why are deserts so dry

Answer 5

prevailing winds have blow over large areas of land - no moisture.

Question 6

define diurnal range, and what it is like in a desert

Answer 6

difference between max and min temperatures over 24 hours
high diurnal range in desert due to little to no clouds

Question 7

how is a camel adapted to the desert

Answer 7

• tough, leathery mouth to eat thorny bush
• long, two layer eyelashes and closeable nostrils to stop sand
• broad, flat hooves to walk on hot sand
• hump stores fat, converts to energy when there is no food

Question 8

how is a cactus adapted to the desert

Answer 8

• some horizontal roots to maximise rare rainfall collection
• taproots 7-10m deep for groundwater
• sharp spikes to avoid being eaten
• leaves waxy and small to reduce water loss

Question 9

what do you call a plant in the desert that changes physical characteristics to survive

Answer 9

xerophytes

Question 10

what do you call a plant in the desert that changes behavioural characteristics to survive

Answer 10

ephermerals

Question 11

what are desert soils like

Answer 11

rocky and sandy, only 1m deep. lack of water and vegetation means there is little organic matter for fertile soil formation

Question 12

what is the thar desert

Answer 12

most densely populated desert in the world, stretching across north west india and into pakistan. mostly within state of rajistan

Question 13

what is climate like in the thar desert

Answer 13

little organic matter, soils not very fertile,
small clumps of vegetation e.g shrubs.
100-240mm annual rainfall
high summer temps, 53 degrees

Question 14

what are the opportunities for development in the thar desert

Answer 14

mineral extraction
tourism
energy
farming

Question 15

how is mineral extraction an opportunity for development in the thar desert

Answer 15

phosphorite - used in fertilisers
gypsum - plaster for construction, nearly all of india’s supply, improves its infrastructure
limestone - used extensively in india’s steel industry in furnaces

Question 16

how is tourism an opportunity for development in the thar desert

Answer 16

• desert safaris on camels
• annual desert festival - locals can provide food and services e.g camel nurture
• tens of thousands annual tourists

Question 17

how is energy an opportunity for development in the thar desert

Answer 17

1. solar - sunny and cloudless climate, ideal conditions for solar power. 40km solar park being built, could power rajasthan
2. wind- jaisalmer wind park, renewable (cheaper, no emissions)
3. industry can develop (electricity), living conditions improve (cooking, lights)

Question 18

how is farming and opportunity for development in the thar desert

Answer 18

• 1958 indira gandhi canal revolutionised farming - wheat and cotton now thrive, growth in commercial farming
• locals survive on their animals and crops

Question 19

what is desertification

Answer 19

process by which fertile land becomes desert, usually as a result of drought, deforestation, or inappropriate farming methods

Question 20

threats of desertification

Answer 20

not just lics - anywhere around fringes of existing deserts
loss of land
1 billion live in areas at risk

Question 21

what are drylands / marginal land

Answer 21

semi arid areas at the fringe of deserts. home to 1 in 3 people. unreliable agriculture due to dryness

Question 22

what are the causes of desertification

Answer 22

climate change
soil erosion
salinisation
population increase
overgrazing/overcultivation
deforestation

Question 23

what is soil erosion

Answer 23

overgrazing, overcultivation, and deforestation leaves soil exposed. topsoil can be blown away, leaving infertile, barren wastelands

Question 23

how does climate change cause desertification

Answer 23

hotter, drier conditions and unreliable rainfall

Question 24

what is overgrazing

Answer 24

excessive grazing by too many cattle, damage to grassland and leads to soil erosion

Question 25

what is overcultivation

Answer 25

excessive growing of crops, degrading quality and exhausting soil and making it vulnerable to soil erosion

Question 26

what are the methods of tackling desertification

Answer 26

zai pits magic stones afforestation water and soil management national parks

Question 27

what are zai pits and how do they tackle deforestation

Answer 27

growing crops in small holes with soil piled around edges to protect from wind. nutrients can also blow in and become trapped with the plant. in the sahel, the holes are filled with manure and compost to provide nutrients. the manure also attracts termites, whose holes can help break up the soil. in the sahel, yield has improved by up to 500%

Question 28

what are stone bunds and how do they tackle deforestation

Answer 28

rows of stone along contours of slopes, to prevent water and nutrients from flowing down the hillside and rather allowing them to soak into the soil. water can be used for irrigation or as local water supply. - labour intensive, small scale

Question 29

what is planting trees and how does it tackle desertification

Answer 29

reduces soil erosion as roots bind soil together. leaves provide shelter for crops and animals. some branches cut off so trees dont take too many nutrients compared to other crops, branches = local firewood

Question 30

pros and cons of water soil management with example

Answer 30

the badhia desert, jordan. used stone walls. water used for newly planted shrubs, which binds soil together. soil improves, plants grow, wildlife attrract. - salinisation

Question 31

what are the challenges of development in the thar

Answer 31

water supply extreme temperatures inaccessibility

Question 32

how is water supply a challenge in the thar desert

Answer 32

population growth + development in farming industry means increasing water demand high temps and low rainfall causes high evaporation rates, water is scarce. - health affected - farming affected - tourism affected however IGC...

Question 33

what is the indira ghandi canal and what opportunities does it have

Answer 33

indias longest canal, over 650km, and main source of irrigation in thar. - commercial farming, wheat and cotton - drinking water for many in desert - enables widespread tree planting/growing, stabilises sand, mitigates soil erosion and desertification

Question 34

how are the extreme temps a challenge in thar desert

Answer 34

- presents health issues esp for those working outdoors. killed hundreds in 51 degree 2016 heatwave - tourism becomes limited to cooler season - low rain + high temps = water shortage - dehydration of plants and animals, affecting farming and biodiversity

Question 35

how is accessibility a challenge in thar desert

Answer 35

extreme weather + vast areas of wasteland means very limited road networks - high temps melts tarmac - strong winds blow sand over road - though public transport offered, buses extremely cramped

Question 36

disadvantages of zai pits

Answer 36

labour intensive and small scale

Question 37

disadvantages of stone bunds

Answer 37

labour intensive and easily broken if not made properly, meaning smaller scale farmers who may not have money or skill to make them remain vulnerable

Question 38

disadvantages of afforestation

Answer 38

trees, especially larger ones, soak up lots of nutrients from the soil, could perhaps restrict amount available for valuable crops