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.
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.
How this is tested: Paper 2, Section A opens with a data table or graph of climate-health figures (e.g. the rise in deaths during a heatwave). You Outline or Describe features of the data -- read carefully and quote the figures and units.
Section B ends with a [10] 'to what extent' essay -- e.g. how far climate change is the chief cause of human migration.
| 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.