O Level Geography: The Natural Environment — Revision Notes (Cambridge 2217)

Related: Theme 2 study guide

Condensed, exam-focused notes for Theme 2 of Cambridge O Level Geography (2217), 2026 series.

2.1 Earthquakes and volcanoes

• Caused by plate movement at boundaries (diverging, converging, sliding past).
• Earthquakes: stress builds along a fault and releases suddenly; effects include ground shaking, tsunamis, building collapse.
• Volcanoes: magma reaches the surface, at constructive (diverging) and destructive (converging) boundaries; effects include lava flows, ash fall, pyroclastic flows.
• Management: building codes, early-warning systems, evacuation planning — always separate the physical cause (plate boundary type) from the human response (management).
• Volcanoes present hazards and offer opportunities for people (e.g. fertile volcanic soils, geothermal energy, tourism) — the syllabus requires both sides.

2.2 Rivers

Course	Dominant process	Typical landform
Upper	Vertical erosion	V-shaped valley, waterfall
Middle	Lateral erosion	Meander
Lower	Deposition	Floodplain, delta

• Hazards: flooding and river erosion. Opportunities of living on a flood plain, a delta or near a river (e.g. fertile alluvial soil, flat land, water supply, transport).
• Flood management: hard engineering (dams, levees, channel straightening) vs soft engineering (floodplain zoning, upstream afforestation) — always state which category a named strategy belongs to.

2.3 Coasts

• The work of the sea and wind in eroding, transporting and depositing.
• Erosion processes: hydraulic action, abrasion, attrition, solution.
• Erosional landforms, by mechanism:
  • Bay and headland coastlines: differential erosion — softer rock is cut back into bays, harder rock is left as headlands.
  • Cliffs and wave-cut platforms: waves cut a notch at the cliff base between the tides, the rock above collapses and the cliff retreats, leaving a gently sloping platform exposed at low tide.
  • Caves → arches → stacks → stumps: waves attack lines of weakness in a single resistant headland; the arch roof collapses to leave a stack, which is worn down to a stump.
• Transport: longshore drift moves sediment along the coast where waves approach at an angle.
• Depositional landforms: beaches; spits (longshore drift carries sediment past a change in coastline direction); coastal sand dunes (wind blows dry sand inland from the beach).
• Hazards (including coastal erosion and tropical storms) and opportunities (e.g. fishing, ports, tourism); management of coastal erosion.
• Coral reefs and mangrove swamps: distinct ecosystems valued for biodiversity and natural coastal protection against erosion/storm surges.

2.4 Weather

• Weather = short-term, day-to-day state of the atmosphere. Climate = long-term average pattern.
• Stevenson Screen: characteristics (white, louvred, raised on legs), siting (open space away from buildings and trees) and use (houses thermometers in shade with free air circulation).
• Instruments: rain gauge (rainfall), maximum-minimum thermometer (highest and lowest temperature), wet-and-dry bulb thermometer or hygrometer (humidity), sunshine recorder (hours of sunshine), barometer (air pressure), anemometer (wind speed), wind vane (wind direction); simple digital instruments; observations of cloud type and amount.
• Make calculations from instrument readings (e.g. temperature range = maximum − minimum; mean or total rainfall).
• Use and interpret graphs and other diagrams showing weather and climate data.

2.5 Climate and natural vegetation

• Two climates: equatorial and hot desert. Two ecosystems: tropical rainforest and hot desert.
• Describe each climate by temperature (mean of hottest month, mean of coolest month, annual range) and precipitation (amount and seasonal distribution; convection and relief rainfall), including from climatic graphs.
• Factors: latitude, pressure systems, winds, distance from the sea, altitude, ocean currents (e.g. equatorial: low latitude, low pressure and rising air, convection rain all year; hot desert: subtropical high pressure and sinking air, distance from the sea, cold offshore currents).
• Equatorial climate / tropical rainforest ecosystem: high, consistent rainfall and temperature; dense, layered canopy vegetation competing for light. Threat: deforestation (causes and effects required).
• Hot desert: very low rainfall, wide diurnal temperature range; vegetation (e.g. cacti) stores water, reduces leaf surface area to limit water loss. Threat: overgrazing, irrigation-driven degradation.
• Always link climate → vegetation adaptation → human impact as one connected chain, not three separate facts.

Exam technique for this theme

Treat this theme as a set of process-then-landform pairs rather than a list of features to memorise in isolation. For both rivers and coasts, always state the formative process (erosion, transportation or deposition) before naming the landform it produces, since Paper questions consistently ask candidates to explain a labelled landform by its process, not simply name it — a landform named without its process earns partial credit at best. Practise sketching and annotating a labelled river long profile and a labelled coastal cross-section from memory, since diagram-based recall is directly examined. For earthquakes and volcanoes, keep the physical cause (plate boundary type) and the human response (hazard management) as two separate mental categories, because exam questions frequently ask for one without the other, and blending them together in an answer costs marks even when both parts are individually correct.

Case study preparation

Every sub-topic in this theme is more securely revised with at least one named, real-world case study attached, since exam questions frequently ask candidates to “describe the impacts of a named earthquake, volcanic eruption, or flood event” rather than only testing generic process knowledge. For each of earthquakes, volcanic eruptions, river flooding, and coastal management, prepare one specific named example with a handful of concrete facts (location, date, scale, and the specific management response used) rather than relying on generic process description alone — a generic answer about “an earthquake” without any named location or date will not access the marks reserved for case-study detail even if the process explanation itself is accurate.

Comparing the two climate zones directly

Because 2.5 is often examined by asking candidates to compare the equatorial and hot desert climates and the tropical rainforest and hot desert ecosystems rather than describe each separately, practise building direct comparison statements rather than two separate descriptions. For instance: rainforest vegetation forms a dense, multi-layered canopy competing for light in conditions of abundant water, while desert vegetation such as cacti reduces leaf surface area and stores water internally in conditions of severe water scarcity — both adaptations respond to the dominant environmental stress of their climate, but that stress is opposite in each case (excess resource competition versus resource scarcity). Human impact follows the same comparative logic: deforestation removes rainforest’s protective canopy and accelerates soil erosion and biodiversity loss, while overgrazing and irrigation-driven degradation in deserts can trigger desertification of already marginal vegetation cover.

Sketching diagrams from memory

Because this theme is examined partly through labelled diagram recall, practise sketching a river’s long profile and a coastal cross-section entirely from memory, then checking your sketch against the study guide’s version and correcting any missing label. Repeating this until the sketch is accurate without reference builds a genuinely reliable exam skill, since a candidate who can label a diagram when shown one but cannot reproduce it unprompted is more exposed than a candidate who has practised the recall itself.

Self-test

1. Name the three ways plates can interact at a boundary.
2. What is the dominant process and typical landform in a river’s middle course?
3. Name two coastal erosional landforms and one depositional landform.
4. Give two features of a Stevenson Screen and explain why each matters.
5. Give one specific vegetation adaptation for hot desert climates and the stress it responds to.

Answers: 1. Diverging, converging, sliding past (transform). 2. Lateral erosion; meander. 3. Erosional: headland/bay, cliff, wave-cut platform, cave/arch/stack (any two). Depositional: beach or spit. 4. Any two of: painted white to reflect the sun’s heat; louvred sides so air circulates freely while direct sunlight is kept off the thermometers; raised on legs so readings are not affected by heat from the ground; sited in the open away from buildings and trees so readings are representative. 5. Reduced leaf surface area (e.g. cacti spines) — responds to water scarcity/heat stress.