Cambridge International AS & A Level Geography (9696): Topic 10 – Hot arid and semi-arid environments – Practice Questions

These are original questions written for Marlbridge, for revision and practice on this content. They are not reproduced past-paper questions, and they do not replicate the exam’s exact structure, question count or mark tariffs – examination boards hold copyright in their own papers. Use these alongside the official past papers from your board or school.

These questions cover topic 10, Hot arid and semi-arid environments (sections 10.1 to 10.4), of the Cambridge International AS & A Level Geography (9696) syllabus for examination in 2025 and 2026. The topic is one of the four Advanced Physical Geography options assessed in Paper 3. All places and data marked as fictional are invented for practice.

Revise first with the study guide and the revision notes. The Cambridge A Level Geography hub and 9696 checklist show where this option fits. For data-response practice on the AS physical core, try the physical geography practice set.

Questions

1. Define aridity using the UNEP aridity index, and state the index range for a semi-arid area. [2]

2. Explain how a cold ocean current can make a west-coast desert more arid. [4]

3. The table shows mean monthly data for Tamberet, a fictional semi-arid weather station at about 14 degrees north.

	J	F	M	A	M	J	J	A	S	O	N	D
Rainfall (mm)	0	0	1	3	12	38	96	128	54	9	1	0
Mean temperature (°C)	23	25	29	32	33	31	28	27	28	29	26	23

(a) Calculate the annual rainfall and the percentage that falls in July, August and September. Show your working. [2] (b) Describe the seasonal pattern of rainfall and temperature shown. [3] (c) Suggest why mean temperature falls in July and August even though the sun is high in the sky. [2]

4. At a fictional site in a hot desert, a rock surface measured 12 °C at 06:00 and 58 °C at 14:00.

(a) Calculate the range between these two readings. [1] (b) Explain how daily changes like this may lead to rock breakdown, and why moisture may also be needed. [4]

5. Distinguish between saltation, traction and suspension as ways that wind transports sediment. [3]

6. With the help of a labelled sketch, explain the formation of zeugen. [5]

7. Explain how episodic rainfall leads to flash floods, and how flash floods help form alluvial fans. [6]

8. Distinguish between physical and physiological drought, and explain two ways plants in hot arid areas are adapted to drought. [5]

9. The table shows changes on the fictional Qasr Nadir irrigation scheme after canal irrigation began without field drainage.

Years since irrigation began	0	5	10	15
Topsoil salinity (EC, dS/m)	1.2	2.6	4.1	5.8
Wheat yield (tonnes per hectare)	3.0	2.8	2.3	1.7

(a) Describe the changes shown, using data. [3] (b) Explain how irrigation without drainage can cause these changes. [4]

10. The fictional Saredh Basin is an enclosed desert basin with a sand sea in its centre and mountains along its edges. Using this setting and your own examples, assess how far wind, rather than water, shapes the landforms of hot arid environments. [12]

11. “Desertification in semi-arid lands is caused by people, so people can stop it.” To what extent do you agree? [12]

12. With reference to a case study of a hot arid or semi-arid environment, evaluate whether small-scale, community-led schemes have managed it more sustainably than large-scale projects. [15]

Answers

1. Aridity is a long-term water deficit, measured by the ratio of precipitation to potential evapotranspiration (P/PET) [1]. A semi-arid area has an index of 0.20 to 0.50 [1]. [2] Examiner insight: A definition based on rainfall alone, such as “under 250 mm”, is weaker because it ignores evaporation.

2. Cold currents (such as the Benguela) chill the air above the sea [1]. Cool air beneath warmer air forms a temperature inversion [1]. The inversion stops air rising, so convection clouds and rain cannot form [1]. Moisture condenses as fog or low stratus rather than rain [1]. [4] Examiner insight: The inversion is the step most answers miss; without it the chain from cold water to no rain is incomplete.

3. (a) 0+0+1+3+12+38+96+128+54+9+1+0 = 342 mm [1]. July to September = 278 mm, which is 278/342 x 100 = 81.3% [1]. [2] (b) Rainfall is concentrated in one wet season, peaking in August at 128 mm [1]. Seven months receive under 10 mm, giving a long dry season [1]. Temperature peaks before the rains, at 33 °C in May, with a range of 10 °C between the warmest and coolest months [1]. [3] (c) Thick cloud during the wet season reduces incoming solar radiation [1]. Rain and moist soils use energy for evaporation, which cools the surface [1]. [2] Examiner insight: “Using data” means quoting figures with units; a description without numbers is held at the lowest mark.

4. (a) 58 - 12 = 46 °C [1]. [1] (b) Rock heats and expands by day and cools and contracts at night [1]. Dark and light minerals expand by different amounts, so stress builds between grains (granular disintegration) [1]. The outer layer changes temperature more than the interior, so shells may peel off (exfoliation) [1]. Laboratory work suggests dry rock rarely breaks from heating alone, so dew or rain probably weakens it through chemical or salt processes [1]. [4] Examiner insight: Use the 46 °C figure in your explanation to show the fictional data has been applied, not ignored.

5. Saltation: sand grains are lifted and bounce along in short hops, mostly near the ground [1]. Traction (surface creep): larger grains are rolled or pushed along the surface, often by the impact of saltating grains [1]. Suspension: fine dust is held up in the air and can travel long distances [1]. [3] Examiner insight: “Distinguish” needs a clear difference for each term, so state particle size or movement type every time.

6. Zeugen form where horizontal bands of hard rock lie over softer rock [1]. Vertical joints in the hard cap are widened by weathering and abrasion [1]. Wind-blown sand abrades most strongly near the ground, where saltation is concentrated [1]. The softer rock beneath is undercut faster, leaving tabular ridges with a hard cap [1]. A sketch labelling the cap rock, soft rock, undercut base and wind direction [1]. [5] Examiner insight: A sketch earns credit only if its labels explain processes, not just name parts.

7. Rainfall in deserts comes in rare, intense storms [1]. Bare, crusted surfaces have low infiltration, so overland flow begins quickly [1]. Water concentrates in channels and rises rapidly as a flash flood with a high sediment load [1]. Where the channel leaves the mountain front, it loses confinement and spreads out [1]. Gradient and velocity fall and water is lost by seepage, so the load is deposited [1]. Coarse material is dropped near the apex and finer material towards the edge, building a cone-shaped fan [1]. [6] Examiner insight: Explain why energy falls at the mountain front; naming the fan without this sequence limits the mark.

8. Physical drought is an actual shortage of water in the soil [1]. Physiological drought occurs when water is present but plants cannot take it up, for example because salty soil water reverses osmosis [1]. Succulents store water in stems or leaves [1] and open their stomata at night to reduce water loss [1]. Phreatophytes grow very deep roots to reach groundwater [1]. [5] Examiner insight: Each adaptation needs both the feature and how it saves or gains water.

9. (a) Salinity rises steadily from 1.2 to 5.8 dS/m, nearly five times higher [1]. Wheat yield falls from 3.0 to 1.7 tonnes per hectare, a fall of 43.3% [1]. The yield decline speeds up after year 5 as salinity rises further [1]. [3] (b) Extra water from canals raises the water table [1]. Close to the surface, water is drawn up by capillary action [1]. High evaporation leaves dissolved salts behind in the topsoil [1]. Salty soil water causes physiological drought, so crops take up less water and yields fall [1]. [4] Examiner insight: Link the two variables; describing salinity and yield separately misses the relationship the question invites.

10. Indicative content (the real exam marks extended answers using levels of response, not point by point):

• Define aeolian (wind) and fluvial (water) processes [1].
• Strong winds and bare surfaces make deserts high wind energy environments [1].
• Wind forms dunes, such as barchans where wind is from one direction [1].
• Abrasion and deflation form yardangs, zeugen and deflation hollows [1].
• Episodic storms on bare ground produce flash floods [1].
• Water cuts wadis and arroyos and builds alluvial fans and bahadas [1].
• Sheet floods help form pediments; playas collect water in enclosed basins [1].
• One flood can move more sediment than years of wind [1].
• Many fluvial landforms are inherited from pluvials, e.g. Lake Bonneville shorelines [1].
• Weathering (salt, thermal) prepares material for both agents [1].
• Balance varies: in the Saredh Basin the central sand sea is wind-dominated, while the mountain edges are water-dominated [1].
• Reasoned conclusion answering “how far” [1]. [12] Examiner insight: High-level answers judge the balance by place and landform rather than listing wind features then water features.

11. Indicative content (marked by levels of response in the real exam):

• Define desertification as land degradation in drylands from climatic variations and human activities [1].
• Natural factor: long droughts, such as those in the Sahel in the 1970s and 1980s [1].
• Natural factor: high rainfall variability reduces plant cover [1].
• Charney’s albedo idea: less vegetation may reduce rainfall further [1].
• Human factor: overgrazing, especially around boreholes [1].
• Human factor: overcultivation and shorter fallows reduce fertility [1].
• Human factor: cutting trees for fuelwood [1].
• Human factor: poorly drained irrigation causes salinisation [1].
• Underlying causes: population growth and settled herders concentrate pressure [1].
• Counter-evidence: regreening as rainfall partly returned shows climate matters [1].
• Interaction: drought starts degradation; land use decides whether it lasts [1].
• Judgement on both halves of the claim: causes are mixed, so human action can reduce but not prevent degradation in drought [1]. [12] Examiner insight: A one-sided answer, all human or all natural, cannot reach the top level on a “to what extent” question.

12. Indicative content using the Sahel (levels of response apply in the real exam):

• Locate the case: semi-arid Sahel, Niger and Burkina Faso [1].
• Problem: low, variable rainfall and a short wet season [1].
• Problem: population growth raises demand for food and fuelwood [1].
• Problem: crusted soils and runoff; shorter fallows [1].
• FMNR began in Maradi in 1983 [1].
• About five million hectares by 2004 [1].
• FMNR is cheap and uses local knowledge [1].
• Zaï pits and stone lines in Yatenga trap water and soil [1].
• Zaï need heavy labour and scarce manure [1].
• Great Green Wall: AU, 2007, target 100 million hectares by 2030 [1].
• A 2020 UN status report found about 4% of the target reached [1].
• Funding gaps and conflict limit progress [1].
• Bottom-up schemes worked better where farmers gained directly [1].
• Sustainability judged on environmental, economic and social grounds [1].
• Supported overall judgement [1]. [15] Examiner insight: Comparing the two scales needs clear criteria for sustainability; without them, the answer stays descriptive.

Where marks are usually lost

• Quoting no figures when the question says “using data”.
• Explaining aridity with “it is hot” rather than pressure, currents or rain shadow.
• Leaving out the temperature inversion when explaining cold-current deserts.
• Confusing saltation and traction.
• Drawing sketches with labels that name features but do not explain processes.
• Ignoring water in desert landform essays.
• Treating desertification as wholly human or wholly natural.
• Describing a case study without judging success against clear criteria.

Next steps

• Check your understanding with our diagnostics.
• Revise exam technique with the 9696 exam preparation guide.
• Book a free trial class for feedback on Paper 3 essays.

Official syllabus

These questions follow the Cambridge International AS & A Level Geography (9696) syllabus for examination in 2025 and 2026, topic 10, sections 10.1 to 10.4. Check the current syllabus on the Cambridge International website.