Outline two physical causes of aridity in hot, arid environments.

Explain two processes of weathering commonly found in hot, arid environments.

“Human activity within periglacial environments is unsustainable.” Discuss this statement.

Sub-tropical high pressure [1] brings dry, descending air [1].

Continentality / interior has higher temperatures than coastal margins [1] due to lack of proximity to the sea [1].

Cold offshore currents [1] mean air does not rise / limits potential precipitation over land [1].

Rain shadow effect [1] means a lack of moisture/rain/water for places on lee side/far side/downwind of relief features/mountains [1].

[4 marks]

Possibilities include:

• exfoliation (involves layers of rock peeling off)
• granular and block disintegration (rock breaks down into grains/blocks)
• freeze-thaw (blocks break off due to ice expansion)
• salt crystal growth (crystals in pores create stress).

Do not credit erosion processes such as sand abrasion.

Award [1] for each process outlined (not simply named) and a further [2] for the brief explanation offered.

For example: Exfoliation involves layers of rock peeling off [1] due to expansion/contraction due to (large) temperature range/changes [1] in the presence of some moisture/water [1].

[6 marks]

Sustainability has been defined in a number of ways. One common one is using resources wisely without compromising the needs of future users. Within an extreme environment the resource base is quite fragile. There are a variety of approaches to analysing the question based on sustainable activities.

Indigenous people have generally lived sustainably in these environments. More recent activity by newer arrivals has not been as sustainable. Human activity includes settlement, infrastructure, communications, and resource development, including tourism. This more recent development has had adverse effects not only on the environment, eg degradation of soil or fauna within ecosystems, but perhaps on the culture of indigenous people.

Good answers may discuss the concept of sustainability and the degree to which environmental, social and economic needs can all be met in periglacial environments. Good answers might be carefully structured around different periglacial environments/places/levels of development and may discuss the extent to which sustainable goals can be met in each.

At band D, two human activities should be described and their sustainability commented on.

At band E, expect either more detailed explanation of different activities, or some discussion of the concept of sustainability in relation to periglacial environments.

At band F, expect both.

Marks should be allocated according to the markbands.

[10 marks]