Hot deserts · GCSE Geography

Physical characteristics

Hot deserts get less than 250 mm of rain a year. Days are very hot, often over 40 °C in summer, but nights can be cold because clear skies let the heat escape.
Soils are thin, sandy or stony and low in nutrients. Plants and animals are spread thinly.
Most hot deserts are around 30° north and south of the Equator, where sinking air creates high pressure, such as the Sahara, the Arabian Desert and the Thar Desert.

Plants: cacti store water in their stems, have spines instead of leaves (so they lose less water) and have long or widespread roots. Some plants' seeds lie dormant until it rains.
Animals: camels store fat in their humps and have wide feet for walking on sand and long eyelashes against blowing sand. Fennec foxes lose heat through their large ears. Many animals are nocturnal, avoiding the daytime heat.

Opportunities: mineral extraction, such as gypsum and limestone; energy, especially wind and solar power (such as the Jaisalmer Wind Park, one of India's largest); farming, made possible by irrigation from the Indira Gandhi Canal; and tourism, such as desert safaris and the fort city of Jaisalmer.
Challenges: extreme temperatures (over 50 °C has been recorded); water supply (low, unreliable rainfall, high evaporation and overused groundwater); and inaccessibility (few roads, and shifting sand dunes).

Desertification is when land on the edge of a desert, in semi-arid areas such as the Sahel, turns into desert.
Causes: climate change (less rain and higher temperatures), population growth, removal of fuel wood, overgrazing, over-cultivation and soil erosion.
Reducing the risk: water and soil management, such as lines of stones ('magic stones') that slow rainwater and trap soil; tree planting, such as Africa's Great Green Wall; and appropriate technology, such as solar cookers that don't need firewood.

Hot desert: An area with less than 250 mm of rain a year and high temperatures.
Nocturnal: Active at night and resting during the day.
Desertification: Land on the edge of a desert becoming desert.
Overgrazing: Too many animals eating the plants, leaving the soil bare.
Over-cultivation: Farming land so intensively that the soil loses its nutrients.
Irrigation: Supplying land with water for crops.
Appropriate technology: Simple, affordable technology suited to local people's needs.