13.1 (what) and 13.2 (why) lead here to impacts — on both the environment and people. Two case studies anchor the chapter: the Great Barrier Reef and the ski industry. Green boxes are case studies you can quote in an answer.
Climate change impacts cascade through natural systems and human societies alike.
The impacts fall into two linked groups. Sorting them this way helps structure an answer.
The “other CO₂ problem” — a chemical impact separate from warming.
The fall in seawater pH as the ocean absorbs excess atmospheric CO₂, forming carbonic acid. The ocean is now about 30% more acidic than in pre-industrial times.
This is separate from warming: even without temperature rise, more CO₂ means more acidic seas — undermining marine food webs from the bottom up.
A warmer, more energetic atmosphere loads the dice toward extreme events.
Climate change increases the frequency and intensity of many natural hazards: heatwaves, droughts, heavy rainfall and floods, intense storms, and — critically for Australia — bushfires.
Driven by record drought and extreme heat, the 2019–2020 fires were among the most severe on record — huge losses of habitat and biodiversity, and serious health impacts from smoke. They are a clear example of how climate change worsens a natural hazard (explored in full in Chapter 14).
Links climate impacts to a contemporary hazard. Concepts: environment, change, interconnection, scale.
EnvironmentChangeInterconnectionHealth, food and livelihoods — the human cost.
Health: more heat-related illness and death; the spread of vector-borne diseases (e.g. dengue, malaria) as mosquito ranges expand; and respiratory harm from wildfire smoke and pollution.
Food: shifting rainfall, higher temperatures and extreme events reduce crop yields and raise pests and disease — threatening food security, especially for poorer farming communities.
Australia's flagship natural system — and a vivid environmental impact.
As sea-surface temperatures rise, heat-stressed corals expel the symbiotic algae (zooxanthellae) that give them colour and food — turning white (coral bleaching). Prolonged bleaching kills coral, cutting biodiversity and disrupting marine food webs. The Reef has suffered repeated mass bleaching events in recent years, monitored by the Australian Institute of Marine Science (AIMS). Warming, acidification, cyclones and runoff compound the stress.
A verified Australian environmental impact with clear cause–effect and management links. Concepts: environment, change, interconnection, sustainability.
EnvironmentInterconnectionSustainabilityAn economic impact — and a lesson in adaptation.
Warmer winters and reduced, less-reliable snowfall shorten ski seasons, cutting visitor numbers and revenue for resorts and the towns that depend on them. Resorts respond by investing in artificial snowmaking, moving to higher altitudes, and diversifying into year-round tourism — adaptations with their own costs and limits.
A verified economic impact with clear adaptation responses — ideal for “evaluate” questions. Concepts: environment, change, sustainability.
ChangeSustainabilityThe Reef (environmental, natural system) and the ski industry (economic, human system) show climate impacts across different systems and scales. Using both demonstrates range.
Check you can do these before moving to 13.4 (Responses).
13.3 covered the impacts. 13.4 Challenges, opportunities & responses looks at what we do about it — mitigation, adaptation and international action — with Costa Rica as the case study of a national response.
Everything in this chapter traces to a source you can check. Watch the explainer, read the primary sources, follow the news, and practise the geographical skills this chapter uses.