IB Geography Option C: Extreme environments

What Option C covers

Option C covers the characteristics of extreme environments: hot and cold drylands, polar and periglacial regions and high altitudes, and what makes them hard places to live, from aridity to permafrost and hypoxia. Physical processes and landscapes: glacial erosion, such as plucking, and landforms such as corries and drumlins; periglacial processes such as freeze–thaw weathering, frost heave and solifluction, and landforms such as pingos; and desert processes such as deflation and exfoliation, with wadis and barchan dunes. Managing extreme environments: nomadic pastoralism and transhumance, desertification and overgrazing, resource frontiers, and ways of finding water, from qanats to fog harvesting. Extreme environments' futures: thawing permafrost and thermokarst, glacial lake outburst floods, new Arctic shipping routes, the Antarctic Treaty, and renewable energy such as concentrated solar power.

Where students slip

• A desert is defined by dryness, not by heat. Antarctica gets so little precipitation that it is the largest desert on Earth, and a cold one.
• Permafrost is defined by temperature, not by ice: it is ground that stays at or below 0 °C for at least two consecutive years. The active layer above it thaws every summer, so frozen ground in winter is not necessarily permafrost.
• Desertification is not deserts advancing across their edges. It is the degradation of land in arid, semi-arid and dry sub-humid areas, through climate variation and human activity such as overgrazing, and it can happen far from any desert.