HSC Geography · Teaching presentation

13.3 Impacts of Climate Change

Environmental & human · the Great Barrier Reef & the ski industry
Laptops down · copy the ✍️ notebook boxes as we go

What we're doing today ✍️ Copy into your notebook

Chapters 13.1 (what the data shows) and 13.2 (why it's happening) lead directly here: the impacts. Climate change is not one problem but a cascade of them, and geographers sort them into two linked groups — effects on the environment (reefs, oceans, ice, weather) and effects on people (health, food, water, livelihoods). This lesson works through both, anchored by two contrasting case studies — the Great Barrier Reef and the global ski industry — so you can write with specific, real-world detail rather than generalities.

By the end you can:

  • split impacts into environmental & human;
  • explain ocean acidification;
  • link climate change to worse disasters;
  • describe human impacts & equity;
  • detail the GBR & ski-industry cases.
Environmental impact — bleached reef
Human impact — flooded homes

Two linked groups ✍️ Copy into your notebook

Impacts divide into environmental and human — but the two are tightly coupled, and the strongest answers show that coupling. A bleached reef (environmental) guts the tourism jobs that depend on it (human); heat and drought stressing crops (environmental) drive hunger and price spikes (human). Keep the categories separate when you list impacts, but link them when you explain.

Environmental

Acidification, coral bleaching, worse storms/floods/fire, rising seas.

Human

Health, falling crop yields, damaged industries, displacement.

They interconnect — a bleached reef hits tourism; failed crops hit health.
Reefs under heat stress
Heat & drought hit people
📘 Syllabus: Human–Environment Interactions · climate change🧭 Skill: Organising impacts
Environmental

Ocean acidification

The “other CO₂ problem” ✍️ Copy into your notebook

Extra CO₂in the air Absorbed by seacarbonic acid pH fallsmore acidic Shells & coralstruggle / dissolve

Separate from warming, but from the same cause: the ocean has absorbed roughly a quarter of all human CO₂ emissions, and that dissolved gas forms carbonic acid. Surface seawater is now about 30% more acidic than in pre-industrial times — a fall of about 0.1 pH units. Lower pH makes it harder for corals, shellfish and plankton to build their calcium-carbonate shells and skeletons, threatening the base of marine food webs. The IPCC rates this as a major, worsening impact.

Acidification, in numbers
  • Ocean absorbs ~25% of human CO₂ emissions.
  • Surface water ~30% more acidic than pre-industrial.
  • pH has fallen ~0.1 units (about 8.2 → 8.1).
  • Harms shell-builders: coral, shellfish, plankton.
  • Threatens the base of marine food webs.
📘 Syllabus: Human–Environment Interactions · climate change🧭 Skill: Reading a process flow
Environmental

More intense disasters

Case study: Black Summer (2019–20)

~24 million hectares burnt · ~3 billion animals killed or displaced (WWF)

An unprecedented drought and Australia's hottest, driest year on record (2019) primed the landscape, and the 2019–20 “Black Summer” bushfires became among the worst ever: roughly 24 million hectares burnt, 33 people killed directly, hundreds more deaths linked to smoke, and an estimated 3 billion animals killed or displaced. Climate change didn't start the fires, but it amplified the natural hazard — hotter, drier, more dangerous fire weather (full detail in Chapter 14).

A compound disaster — climate change amplifying a natural hazard.
Record drought primed the landscape
…and extremes swing both ways
📘 Syllabus: Human–Environment Interactions · climate change🧭 Skill: Interpreting a case study
Human

Impacts on people

Health, food & livelihoods ✍️ Copy into your notebook

The human toll runs across four fronts — and it lands unevenly. The IPCC finds that the people and places that did least to cause climate change are often hit hardest by it, a gap it calls a matter of climate justice.

Health

Heat illness, disease spread, smoke.

Food

Lower yields; food insecurity.

Water

Scarcity & drought.

Economy

Damaged industries; displacement.

🤔 Reflect & discuss

Why do the poorest communities often suffer most, though they emit least?

The equity problem
  • They depend on climate-sensitive livelihoods.
  • They live in exposed places (floodplains, drylands).
  • They have fewer resources to adapt.
  • So harm and responsibility are mismatched.
📘 Syllabus: Human–Environment Interactions · climate change🧭 Skill: Environmental & social equity
Case study

The Great Barrier Reef

Coral bleaching ✍️ Copy into your notebook

Healthyalgae give colour& food Heat stresscoral expelsits algae Bleachedwhite; starves ifstress persists

Coral lives in symbiosis with tiny algae (zooxanthellae) that give it both colour and food. When water stays too warm for too long, the coral expels the algae, turns bone-white — bleaches — and starves if the heat persists. The Great Barrier Reef has suffered repeated mass bleaching events — 2016, 2017, 2020, 2022 and 2024 — monitored by AIMS. 2024 formed part of the fourth-ever global bleaching event.

Bleaching, in numbers
  • GBR mass bleaching: 2016, 2017, 2020, 2022, 2024.
  • The 2016 event killed ~29% of shallow-water coral.
  • 2024 = the fourth-ever global bleaching event.
  • Trigger: sea temps ~1°C above the summer max for weeks.
  • Bleached coral can recover if the heat stress eases.
📘 Syllabus: Human–Environment Interactions · climate change🧭 Skill: Cause & consequence
Case study

The ski industry

Warming winters ✍️ Copy into your notebook

Mountain regions warm faster than the global average — the European Alps have warmed about 2°C since the late 1800s, roughly double the global figure. Less snow, and less reliable snow, means shorter seasons, fewer visitors and lost revenue across resorts in the USA and Europe. The industry adapts — artificial snowmaking, moving lifts to higher altitudes, and pivoting to year-round mountain tourism — but each fix carries real costs (snowmaking is water- and energy-hungry) and hard limits: you cannot make snow in warm air.

  • Adaptations: snowmaking, higher altitudes, year-round tourism.
  • Each has real costs & limits.
An economic impact — contrast with the GBR (environmental).
Shorter, less-reliable seasons
Warmer winters shrink the snowpack
📘 Syllabus: Human–Environment Interactions · climate change🧭 Skill: Evaluating adaptation

Watch: the reef under stress ✍️ Copy into your notebook

This ABC News report covers scientists' warnings of catastrophic mass bleaching on the Great Barrier Reef. It puts footage and faces to the process in the diagram — heat stress, the loss of colour, and what repeated bleaching means for a reef that supports thousands of species and a multi-billion-dollar tourism industry.

▶ Watch: Scientists warn of catastrophic coral bleaching on Great Barrier Reef | ABC News — ABC News (Australia) (click → opens on YouTube)

As you watch, note: (1) what sea-temperature trigger the scientists point to; (2) how they describe the scale of the bleaching; (3) one human consequence (tourism, jobs) they raise.

📘 Syllabus: Human–Environment Interactions · climate change🧭 Skill: Synthesising evidence

Sources & explore further ✍️ Copy into your notebook

Every claim about the reef and the climate here traces back to a primary source — a monitoring agency, a management authority or an assessment report. Use them to check the data and to build your case study. Naming and citing a source is exactly what lifts a Band 5–6 response above a Band 3–4 one.

Primary source — original monitoring data or an official report, not someone's summary of it. Cite these, not a random blog.
📘 Syllabus: Human–Environment Interactions · climate change🧭 Skill: Referencing sources

Extended response ✍️ Copy into your notebook

“Examine the environmental and human impacts of climate change, using specific examples.”
Intro — impacts on environment + people, interconnected.
Environmental — acidification; coral bleaching (GBR).
Human — health, food; the ski industry.
Interconnection & equity — who is hit hardest.
Conclusion — wide-ranging, uneven; needs response (→ 13.4).
Marks come from
  • Both environmental AND human impacts.
  • Specific case studies (GBR, ski, Black Summer).
  • Showing interconnection between impacts.
  • Naming the mechanism (heat → bleaching).
📘 Syllabus: Human–Environment Interactions · climate change🧭 Skill: Extended response

Glossary recap ✍️ Copy into your notebook

Ocean acidification — falling seawater pH as it absorbs CO₂ — harms shell-builders.
Coral bleaching — heat-stressed coral expels its algae, turning white and starving.
Zooxanthellae — the symbiotic algae that give coral colour & food.
Food security — reliable access to enough safe, nutritious food.
Adaptation — adjusting to reduce harm from climate impacts (e.g. snowmaking).
Vector-borne disease — illness spread by organisms (e.g. mosquitoes) whose range warming expands.
Equity — fairness — here, the mismatch between who causes and who suffers harm.
Natural hazard — an extreme natural event (fire, flood, storm) that can harm people & environments.
Biodiversity — the variety of living things — lost when reefs bleach or forests burn.
Next lesson

13.4 — Challenges, opportunities & responses

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