Hot, arid and semi-arid environments
Practice Flashcards
Flip to reveal answersWhat is an extreme environment?
Track your progress — Sign up free to save your progress and get smart review reminders based on spaced repetition.
All 12 Flashcards — Hot, arid and semi-arid environments
Sign up free to track progress and get spaced-repetition review schedules.
Question
What is an extreme environment?
Answer
A place whose **harsh physical conditions** make life and human activity very difficult (e.g. hot deserts).
Question
Define a hot desert (rainfall).
Answer
A hot, **arid** environment receiving **under ~250 mm** of rain a year, with far more evaporation than rainfall.
Question
Define a semi-arid environment.
Answer
The drier **margins** of deserts, ~**250-500 mm** of rain a year, sparse grass/scrub and prone to drought.
Question
What is aridity?
Answer
A **permanent water deficit** - potential evaporation exceeds rainfall, so water is always scarce.
Question
What is the diurnal temperature range in deserts?
Answer
The **large gap** between hot days and cold nights - clear skies and bare ground lose heat fast at night.
Question
Sub-tropical high pressure - why does it dry deserts?
Answer
Air that rose at the equator **sinks** at ~20-30 degrees; sinking air **warms and dries**, so rain cannot form.
Question
Rain shadow - how does it cause aridity?
Answer
Mountains force air to rise and drop rain on the windward side, leaving the **leeward side dry** (e.g. the Atacama behind the Andes).
Question
Cold ocean current - effect on rainfall?
Answer
It **chills the air**, so little moisture evaporates onto the land - keeping coasts like the Atacama and Namib arid.
Question
What is continentality?
Answer
Being **far from the sea**, so moist air rarely reaches the interior (e.g. the Gobi, central Australia).
Question
Two named hot deserts and what dries each?
Answer
**Sahara** - sub-tropical high pressure + continentality; **Atacama** - rain shadow of the Andes + a cold current.
Question
Why is the Sahel an extreme environment?
Answer
Its rainfall is **low, seasonal and unreliable**, bringing **drought, flash flooding and water scarcity**.
Question
Name one response to desert water scarcity.
Answer
**Desalination** - removing salt from seawater (e.g. Saudi Arabia, the UAE), where there are almost no rivers.
Read the notes
Full study notes for Hot, arid and semi-arid environments
Topic 9.1 hub
The characteristics of extreme environments
More from Topic 9.1
All flashcards in this topic
Geography exam skills
Paper structures & tips
Track your progress with spaced repetition
Sign up free — Aimnova tells you exactly which cards to review and when, so you remember everything before your IB exam.
Start Free