Hot deserts: water, adaptation and development
Explain aridity and ecological adaptations, then compare development choices and desertification pressures.
Explain aridity and adaptation
Low rainfall defines aridity, though deserts also differ in temperature and seasonality. Descending subtropical air, rain shadows and distance from moisture sources can contribute.
Plants may limit water loss, store water or use extensive roots. Animals may avoid daytime heat. Explain an adaptation through the water or energy problem it addresses.
Worked example
A fictional climate record has 120 mm rainfall and 900 mm potential evapotranspiration annually. The 780 mm difference indicates strong atmospheric demand, not a direct measured groundwater loss.
Common mistake: Every desert is not permanently hot, and rainfall can be highly variable.
Compare development opportunities
Solar energy, minerals, tourism and irrigated farming can generate work and income. Water demand, extreme heat, distance and infrastructure costs constrain projects.
Evaluate the activity’s location, resource needs and users. A solar plant’s installed capacity is not its annual energy production.
Worked example
A fictional farm needs 500 m³ water per hectare for a stated period. Expanding from 20 to 30 ha adds 5,000 m³ demand; supply reliability must be assessed separately.
Common mistake: An economic opportunity can create pressure on a scarce water source.
Explain desertification mechanisms
Land degradation in drylands can involve loss of vegetation, soil structure and productive capacity. Drought interacts with grazing, cultivation, fuelwood demand and institutions.
Less vegetation can expose soil to erosion and reduce infiltration, increasing runoff. Management must suit land users and rainfall conditions.
Worked example
Fictional vegetation cover falls from 40% to 25%: −15 percentage points, a 37.5% relative reduction. The record needs season and survey consistency before linking it to degradation.
Common mistake: Desertification is not simply a desert advancing as a uniform wall.
Try a different resource
Climate graphs
Use the accompanying exact monthly values for calculations. Both axes begin at zero.
Scroll the diagram sideways to see the full resource.
| Month | Rainfall (mm) | Temperature (°C) |
|---|---|---|
| Jan | 83 | 7 |
| Feb | 79 | 8 |
| Mar | 113 | 11 |
| Apr | 89 | 14 |
| May | 29 | 18 |
| Jun | 21 | 21 |
| Jul | 32 | 23 |
| Aug | 35 | 22 |
| Sep | 22 | 19 |
| Oct | 21 | 15 |
| Nov | 85 | 11 |
| Dec | 107 | 8 |
Resource description
Jan: 83 mm, 7°C; Feb: 79 mm, 8°C; Mar: 113 mm, 11°C; Apr: 89 mm, 14°C; May: 29 mm, 18°C; Jun: 21 mm, 21°C; Jul: 32 mm, 23°C; Aug: 35 mm, 22°C; Sep: 22 mm, 19°C; Oct: 21 mm, 15°C; Nov: 85 mm, 11°C; Dec: 107 mm, 8°C
Write an explanation
Check your answer
- Connect each opportunity to the physical setting.
- Explain water and access constraints.
- Evaluate environmental and social distribution of outcomes.
- Identify evidence still needed for a full named desert case.
Practise and review a written answer
Case studies
Desert springs in Death Valley · Concentrated solar power at Noor Ouarzazate · Desert conditions at Joshua Tree
These pages provide selected evidence. Check the whole case requirement with your teacher.
Read further
- www.aqa.org.uk — source or course reference
- www.aqa.org.uk — source or course reference
- qualifications.pearson.com — source or course reference
- www.sqa.org.uk — source or course reference
Ecosystem interdependence · Water security and competing uses · Adaptation to changing conditions
Course links
AQA GCSE Geography · Higher Geography
Next topics
Water resources: reliable supply and competing uses · Energy resources: demand, generation and decisions
Selected teaching sequence with fictional worked data. The linked case records supply bounded evidence; they do not satisfy every course case requirement.
Scottish links identify reusable parts of the topic. Scottish landforms, soil, weather and disease requirements need additional course-specific teaching.