HSC Geography › Human–Environment Interactions › 13.2

Teacher Lesson Plan — Causes of Climate Change

NSW Stage 6 Geography (2022) · Climate change · ~70 min
Teacher copy — includes model answers

At a glance

Companion resources

Big idea

Natural causes (orbital cycles, volcanoes) can't explain the recent, rapid warming; human disruption of the carbon cycle and the enhanced greenhouse effect can — and the 800,000-year CO₂ record clinches it.

Syllabus mapping (NESA Geography 11–12, 2022)

Focus area: Human–Environment Interactions · Content: climate change — the environmental (natural) and human causes of climate change.

Outcomes addressed

GE-11-02 processes & influences across scalesGE-11-01 characteristics & patternsGE-11-05 analyses sourcesGE-11-08 mathematical techniquesGE-11-09 communicates

Outcome codes: source used GE-12-x; re-mapped to GE-11-x (Year 11 Preliminary). Verify against your scope & sequence.

Key concepts

environmentchangeinterconnectionscale

Lesson sequence & timings

TimePhaseTeacher / student activity
0–8HookDeck title (volcano vs industry). “Which of these is driving today's warming?” Activity 1 (sort causes).
8–22Rule out natureSlides 5–8: ice-age cycles & Pinatubo. Activity 2 (rule out) + Activity 3 (Pinatubo data).
22–38Carbon cycleSlide 10 + Activity 4 (label the cycle). Emphasise net rise from fossil fuels + deforestation.
38–50GreenhouseSlide 12: natural vs enhanced greenhouse. Address the misconception that “greenhouse effect” is inherently bad.
50–62The clincherSlide 14 + Activity 5 (800,000-yr graph). This is the killer evidence.
62–70ConsolidateActivity 6 essay plan. Exit ticket: one reason nature can't explain today's warming.

Activities — model answers

Activity 1 · Sort the causes

Model
Natural: orbital cycles, volcanic eruptions, solar output, ocean circulation. Human: burning coal, deforestation, enhanced greenhouse effect, fossil-fuel transport.

Activity 2 · Rule out natural

Model
Orbital cycles: far too slow and out of step with the orbital schedule. Volcanoes: cause short-term cooling, and their CO₂ is far less than human emissions. Solar output: has been roughly flat/slightly declining while temperatures rose — so it can't be the driver.

Activity 3 · Pinatubo

Model
~20 million tonnes of SO₂; cooled Earth ~0.5 °C for 1–2 years. Cooling, because SO₂ and ash reflect sunlight. Volcanic CO₂ is a small fraction of human emissions, so it can't drive sustained warming.

Activity 4 · Carbon cycle

Model
Photosynthesis; sink; fossil fuels; deforestation; net rise. Summary: humans add carbon (fossil fuels) faster than the sinks can remove it, and deforestation shrinks the sinks — so atmospheric CO₂ climbs.

Activity 5 · 800,000-year graph

Model
Naturally CO₂ stayed below ~300 ppm; today it is over 420 ppm, spiking after ~1950. It's strong evidence because current CO₂ is outside the entire natural range of 800,000 years and the spike aligns with industrialisation — natural cycles can't produce it.

Activity 6 · Essay plan

Model plan
Intro: define natural vs human causes. Rule out nature (cycles too slow; volcanoes cool & emit little CO₂; flat solar). Human causes: carbon-cycle disruption + enhanced greenhouse. Clincher: 800,000-yr CO₂ record. Conclusion: the evidence points clearly to a human cause.

Key questioning (with answers)

Differentiation & assessment

Support

  • Provide cause cards to physically sort (Activity 1).
  • Sentence frames for “rule out” explanations.

EAL/D

  • Pre-teach: orbital, sulphur dioxide, sink, sequester, enhanced.

Extension

  • Research the solar-output evidence (why the sun isn't the cause).
  • Compare methane vs CO₂ as greenhouse gases.

Assessment / homework

  • Write the Activity 6 extended response in full.

Useful resources & recent articles

Accuracy reminder: Pinatubo cooling is usually cited as ~0.5 °C; volcanic-vs-human CO₂ ratios and current CO₂ update — cite sources.
Rose Bay Secondary College · HSC Geography · Human–Environment Interactions — Teacher plan (13.2) · NESA Stage 6 (2022) · HSC 2026
Aligned to the NESA Geography Stage 6 Syllabus (2022); facts verified to public sources; figures redrawn (no textbook images reproduced).