The big idea: Climate change does not only reshape the environment -- it directly threatens human health and wellbeing.
Higher temperatures, extreme weather and shifting conditions create health hazards: heat illness, the spread of disease, dirty water, food and air problems, and the stress of being forced to move.
The harm is uneven -- the old, the very young, the sick and the poor suffer most.
Key terms
- Health hazard -- something in the environment that can cause illness, injury or death.
- Heat stress -- the body overheating; it can cause heatstroke, dehydration and heart strain.
- Vector-borne disease -- an illness spread by an animal carrier (a vector), such as malaria spread by mosquitoes.
- Climate migrant -- a person forced to move because climate change makes their home unlivable.
How heat turns into a health hazard
- Direct heat stress -- hotter days cause heatstroke, dehydration and extra strain on the heart, especially during heatwaves.
- Disease spreads further -- warmth lets mosquitoes and other vectors survive in new, cooler areas, spreading malaria and dengue.
- Dirtier water and food -- heat speeds the growth of bacteria, so diarrhoeal disease and food poisoning rise.
- Worse air quality -- heat helps form ground-level ozone and smog, harming people with asthma and heart disease.
Explain two ways in which higher temperatures could increase health hazards for people.
Model answer plan
See the mark-by-mark plan — for / against / judgement, with marking guidance — in study mode.
Develop the link: Explain needs a chain, not a label: hotter air -> mosquitoes survive higher up -> malaria spreads to new people. A named hazard with no mechanism scores low.
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Distinct health hazards from climate change
- Heat illness -- the 2003 European heatwave is linked to tens of thousands of extra deaths, mostly elderly.
- Spreading disease -- as East African highlands warm, malaria has appeared at altitudes once too cool for mosquitoes.
- Water and food insecurity -- repeated droughts in the Horn of Africa cut harvests, raising malnutrition.
- Mental health and displacement -- families forced from flooded land in Bangladesh face stress, lost livelihoods and crowded resettlement.
Suggest two distinct health hazards that could result from climate change, developing each one.
Model answer plan
See the mark-by-mark plan — for / against / judgement, with marking guidance — in study mode.
How this is tested: A bar chart of heatwave deaths -- the percentage rise in mortality broken down by age and district -- is a classic climate-health stimulus. Your job is to Outline [2] features of the data: read the key, then state who was hit hardest and quote the figures and units.
Later the same topic returns as a [10] 'to what extent' essay on whether climate change will become the chief cause of human migration.
Read the axis units first. Which group has the tallest bar, and which the shortest?
Interactive diagram
Explore the labelled diagram, charts and maps for this topic in full study mode.
Outline two features of how deaths changed during the heatwave, using the chart.
Model answer plan
See the mark-by-mark plan — for / against / judgement, with marking guidance — in study mode.
| City group | Increase in deaths during the heatwave (%) |
|---|---|
| Over-65s, low-income districts | +38 |
| Over-65s, high-income districts | +15 |
| Working-age adults, all districts | +9 |
| Children under 5, all districts | +12 |
IB-style question -- read the heatwave table
Using the table, outline two features of how deaths changed during the heatwave. [2]
How to answer each feature
- Feature 1 -- who suffered most. Deaths rose most for over-65s in low-income districts (+38%) -- the largest increase in the table.
- Feature 2 -- the gap between groups. The increase was far smaller for working-age adults (+9%), so the elderly and the poor were hit hardest.
Final answer
2 marks: 1 per valid feature read from the data, with the figure quoted (e.g. +38% for poor over-65s; the much smaller +9% for working-age adults).
The [10] essay: climate change and migration: A common [10] asks: to what extent will climate change be the chief cause of human migration?
Use a For / Against / Judgement structure anchored to named examples -- the answer-plan in the summary shows the full shape.