1B - Hot Deserts

Where are hot deserts?

They line the tropics (30degrees N/S of equator)

Characteristics of Hot Deserts

- Very low rainfall

- High daytime temperature but cold nights (no clouds)

- Sandy and stony soil - infertile as limited organic matter form leafy vegetation

- Saline soil - evaporation of surface water draws up salt

- Diversity of plants and animals with adaptations

Adaptations of animals in hot deserts (3)

- Nocturnal rodents live in burrows

- Snakes and lizards have waterproof skin which retains moisture

- Camels can go days without water (humps metabolise into water etc.)

Adaptations of plants in hot deserts

- Small leaves, spines, and waxy surfaces to reduce transpiration

- Succulent plants - store water in stems/leaves

- Long taproots to reach groundwater stores and cover lots of surface area

Consequence of Desertification

Soil Erosion - vegetation destroyed leaves soil exposed to wind and rain causing infertile soil and so can't be used for farming

Causes of Desertification

- Overgrazing - population pressure means too many animals with limited vegetation

- Over cultivation - population pressure means more farming for food

- Deforestation - e.g. for fuel or logging

- Salinisation - e.g. irrigation water evaporates leaving salt or evaporation draws salty water up from underground, killing plants on the way

Reducing Desertification

- Tree planting - reduces soil erosion, provides shade, grazing for animals, and fuelwood

- Legal protection - e.g. national park in Thar Desert

- Irrigation management to ensure salinisation avoided

- Appropriate technology - like magic stones in Burkina Faso (ponding bank which encloses an area of water and soil)

Thar Desert Facts

- North-west India into Pakistan

- Most densely populated desert in the world

Thar Desert Opportunities - Mineral Extraction

- Valuable reserves:

> Gypsum

> Phosphorite

etc.

- Exported across the world --> income for development (NEE)

- Used locally in India e.g. phosphorite fertiliser to help grow crops

Thar Desert Opportunities - Tourism

- Popular destination:

> Camel riding

> Desert safaris

> Beautiful landscapes

> Indian desert festival every winter

- Locals provide:

> Food

> Accommodation

> They are tour guides

Thar Desert Opportunities - Energy

Global:

- Oil can transform local economy, can also be exported

Local:

- Wind farms (very windy) - Jaisalmer wind farm is largest in India (also city for tourism)

- Solar (no clouds) provide energy for locals

- Coal - energy plant constructed in India

Thar Desert Opportunities - Farming & Irrigation

Global:

- Irrigation makes farming possible (Indira Ghandi Canal 1958) e.g. sesame seeds

- Canal has revolutionised wheat and cotton farming

Local:

- Subsistence grazing of animals in grassy areas

- Fruit and veg cultivation

Thar Desert Challenges - Extreme Temperatures

- Can reach above 50 degrees Celsius in June

- Working as a farmer can be difficult

- High evaporation rates --> water shortages

- Plants + animals can die --> must adapt to conditions

- Livestock need shade during the day

HOWEVER:

- People work in the evening instead

- Huts designed to circulate air in a cool way

- White clothes

- Trees/barns shade livestock

Thar Desert Challenges - Water Supply

It is scarce because:

- Low rainfall

- High wind and temperatures so more evaporation

- Increase in population has developed farming and industry which increases demand (and for the people)

Few sources:

- Natural/man made ponds

- Few intermittent rivers/streams

- Underground aquifers requiring wells although usually saline (salty) and bad quality anyway

HOWEVER:

-Canal supplies water

- Settlements built along rivers/streams

Thar Desert Challenges - Accessibility

- Extreme weather and dry areas limit road networks

- High temperatures melt road tarmac

- High wind speed blows sand over the roads

- Many places are only accessible by camel

- Public transport often overpacked

HOWEVER:

- Roads constantly resurfaced

- 4x4 buses used