G7 · Hot deserts | AQA GCSE Geography

Revise the key ideas

Hot deserts are very dry environments, often receiving less than 250 mm of rain a year. Many lie around 30° north and south where air sinks in subtropical high-pressure belts.
Rainfall is low and unreliable, and evaporation can exceed precipitation. Daytime temperatures may be very high, but clear skies allow rapid cooling at night.
Soils often contain little organic matter because vegetation is sparse. Water loss by evaporation can leave salts near the surface; irrigation can worsen salt build-up if drainage is poor.
Water controls the links between soil, plants, animals and people. Rain can trigger rapid plant growth, but long dry periods limit food and reduce farming reliability.
Some plants store water in fleshy stems, have waxy surfaces or small leaves/spines that reduce water loss. Shallow spreading roots capture brief rainfall; deep roots can reach groundwater in some species.
Some animals shelter in burrows or are active at night to avoid daytime heat. Conserving water through concentrated urine or obtaining water from food helps certain species survive.
Biodiversity is often lower than in rainforests but is still important. Desert organisms have specialised adaptations, and trampling or vehicle damage can take a long time to recover.

Mineral extraction can provide jobs and export income, but needs roads, energy and water and can damage habitats. Deposits and economic opportunities vary between deserts.
Strong sunshine can support solar energy projects. Oil and gas extraction occurs in some deserts, but brings pollution risks and does not provide renewable energy.
Farming may use irrigation or follow seasonal rainfall. Reliable water can increase food production, but excessive groundwater pumping depletes supplies and poor irrigation can cause salinisation.
Tourism can provide income through desert scenery, wildlife and cultural heritage. It also needs water and waste management; vehicles and large developments can damage fragile habitats.
Extreme heat can make outdoor work dangerous and increase cooling demand. Large distances, sparse roads and shifting sand can make access and transport expensive.
Scarce water creates competing demands between homes, farming, tourism and industry. Sustainable development considers both present use and whether supplies can recover.

Desertification is land degradation in drylands, reducing soil quality and biological productivity. It does not simply mean sand dunes spreading over fertile land.
Climate change can increase heat and drought stress in some drylands. When vegetation dies back, bare soil is more exposed to wind and water erosion.
Population growth can increase demand for crops, grazing land and fuel wood. Removing trees and shrubs exposes soil and reduces roots that bind it together.
Overgrazing removes plants faster than they regrow and livestock can compact soil. Less infiltration and more runoff can increase erosion.
Over-cultivation can exhaust nutrients and damage soil structure. Shorter fallow periods may leave soil less fertile, reducing plant cover and yields.
Erosion removes fertile topsoil, making plant growth harder. This creates a feedback: less vegetation leads to more erosion, which further reduces vegetation.
A land-degradation feedback. The final stage reinforces vegetation loss. Keeping soil covered and managing water can interrupt this feedback.
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Water management includes rainwater harvesting, drip irrigation and using crops suited to local rainfall. Efficient irrigation needs drainage to reduce salt accumulation.
Soil management includes keeping vegetation cover, adding organic matter and contour barriers that slow runoff. Stone lines or small planting pits can trap water and sediment where suitable.
Tree planting can stabilise soil, provide shade and reduce wind erosion. Native or locally suitable species and long-term care matter more than planting large numbers without survival checks.
Appropriate technology is affordable, maintainable and suited to local needs. Small water-harvesting systems or efficient cooking stoves can reduce pressure on water and fuel wood.
Rotational grazing and limits on herd pressure allow vegetation to recover. Measures work best when communities help plan them and have secure access to land and alternative livelihoods.

The Thar Desert stretches across northwest India and southeast Pakistan. This case study focuses on western Rajasthan in India, around places such as Jaisalmer, where rainfall is limited and summer temperatures can exceed 45°C.
Mineral and energy resources provide opportunities: gypsum and building stone support mining, while petroleum extraction around Barmer creates jobs and income. These activities need transport and can disturb land and use scarce water.
High sunshine levels support solar power, including large developments in western Rajasthan. Electricity and jobs are benefits, while land use, transmission lines and habitat disturbance need management.
Rain-fed crops and livestock depend on variable rainfall. The Indira Gandhi Canal supplies water to northwest Rajasthan, enabling irrigated farming; water distribution, maintenance and soil salinity remain challenges.
Tourists visit Jaisalmer's heritage sites and desert dunes. Guides, accommodation and local crafts earn income, but camps, vehicles and water demand can pressure the environment.
Extreme heat limits outdoor work and raises cooling needs. Water scarcity constrains households and farms, while scattered settlements, sand and long distances make some desert areas expensive to serve even though towns have developed transport links.
Development opportunities are not spread equally across the whole Thar. A clear answer connects each named activity to its benefit and a specific environmental or practical challenge.

50 questions · Random sets of 10. These quick checks support revision; practise longer explanations and justified judgements too.