(i) Define the term desertification.

(ii) Describe the pattern of areas with a high risk of desertification shown on the map.

Suggest three reasons why some rainstorms in hot, arid environments result in flash floods.

Examine how human activity may be affected by global climate change in one named extreme environment.

(i) The spread/intensification of desert/arid conditions. Credit alternative phrasing which implies change, such as turning/becoming eg “the desert has expanded”.

(ii) Award [1 mark] for each of the following to a maximum of [3 marks]:

• adjacent to existing deserts
• identification of anomalies eg, Western Australia 
• limited to central and western Australia (not east)
• reference to place names/tropics/latitude.

Award [1 mark] for each reason and [1 mark] for a suggested link with flooding.

Reasons could include:

• torrential precipitation [1 mark] leads to overland flow/surface water [1 mark]
• precipitation exceeds infiltration rate [1 mark] thereby causing overland flow [1 mark]
• sparse vegetation leads to less interception [1 mark] and rapid run-off/less storage [1 mark]
• run-off may be rapidly concentrated in wadis and canyons [1 mark] which overflow [1 mark]
• nature of desert surfaces (crusts, rocky, impermeable) [1 mark] also causing rapid run-off [1 mark].

Award a maximum of [4 marks] if the reasons do not clearly relate to flash floods in an arid environment, as opposed to generic flooding.

Candidates may choose to approach this question in terms of current observable changes or predicted change. Either approach is acceptable.

In cold environments, melting permafrost may give benefits or costs. Benefits could include longer growing seasons, potential for sedentary agriculture, potential for commercial forestry, more rainfall in cold environments, more potential for tourism, and increased accessibility of minerals. There may also be less, but unpredictable sea ice making sea routes more accessible but potentially more hazardous/increased fish availability due to changing sea conditions (increasing fishing potential).

Problems could include traditional ways of life based on hunting and fishing are threatened; out-migration of the younger people, unstable buildings and infrastructure.

Possible loss of snow and its impact on ski resorts in mountainous areas, and the loss of water supply from retreating glaciers, impacting on a range of human activities, is also a valid response.

In hot environments: changes in rainfall patterns may give benefits or costs, benefits may lead to better grazing potential, more food production and more reliable water supplies. Lower rainfall could make marginal land impossible to live on as grass disappears and fuel wood becomes limited. Rainfall patterns could become more extreme, either more flash floods or extreme droughts. Food shortages may become more frequent/intense leading to environmental migration.

Award credit for an evaluation that takes a considered view of how wealthy people in extreme environments may be in a better position to adapt to change eg, water management in Dubai.

Do not credit tropical rainforests.

At band D, expect some description of two ways in which human activity may be affected by climate change in a recognizable extreme environment.

At band E expect either a more detailed account of a greater range of impacts, or some explicit evaluation of a variety of different kinds of impact (positive/negative or short-term/long-term).

At band F, expect both.

Marks should be allocated according to the markbands.

There was little difficulty in defining the term desertification. The map question was generally well answered, although weaker candidates did not refer to places on the map, or refer to latitude, longitude and the Tropic of Capricorn.

This question was generally well done, with good knowledge and understanding of the causes of flash floods in deserts.

This question did not cause significant problems, as long as candidates related the human activity to a specific extreme environment. There were some good case studies, such as the loss of snow/glaciers in Switzerland and a change in economic focus. Permafrost or cold areas were done better than the rather repetitive attempt to relate the question to arid areas. Weaker responses tried to look at climate change as a whole and were not related to a named extreme environment.