Extreme Environments is a core part of IB Geography. Revise the key concepts and common mistakes below, then lock them in with the free games.
Hot desertRegion receiving less than 250 mm precipitation per year, with high diurnal temperature range.
SaharaWorld's largest hot desert at approximately 9.2 million km², stretching across North Africa.
WadiDry channel that experiences flash floods during rare rainfall events.
XerophytePlant adapted to arid conditions through deep roots, small leaves or water storage.
SahelSemi-arid transition zone south of the Sahara, particularly vulnerable to desertification.
Great Green WallAfrican initiative since 2007 to plant trees across the Sahel to combat desertification.
Antarctic Treaty (1959)Agreement designating Antarctica for peaceful, scientific use; in force from 1961.
PermafrostPermanently frozen ground, ranging from continuous to sporadic, that thaws in surface 'active layer'.
Katabatic windCold dense air flowing downhill from ice plateaux, often reaching destructive speeds.
Ice shelfFloating extension of glacier ice over the ocean.
KrillSmall crustacean that anchors the Antarctic food web supporting whales, seals and penguins.
Madrid Protocol (1991)Environmental protocol to the Antarctic Treaty designating the continent a 'natural reserve devoted to peace and science'.
OrogenyProcess of mountain building through tectonic collision, e.g. Himalayan orogeny from ~50 Ma.
Altitude sicknessAcute mountain sickness from low oxygen, beginning above ~2,500 m.
Questions where students often pick the tempting wrong answer — make sure you know the right one: