Food and water security
Big idea: Climate change threatens food security and water security through changing rainfall, temperatures, and extreme events.
Impacts on agriculture
- Changed growing conditions: Some crops may fail; growing zones shift poleward
- Water stress: Drought reduces yields; changed monsoon patterns affect irrigation
- Extreme weather damage: Floods, storms, heatwaves destroy crops
- New pests and diseases: Warmer temperatures allow expansion to new areas
- Soil degradation: Increased erosion from intense rainfall; desertification
Impacts are uneven — some regions may benefit (longer growing seasons), but most will face challenges. LEDCs are often most vulnerable.
Water resources
- Glacier melt: Initially more water, then less as glaciers disappear
- Changed precipitation: Some regions drier, others wetter; more flooding
- Groundwater depletion: Increased demand during droughts
- Saltwater intrusion: Sea level rise contaminates coastal aquifers
- Water quality: Higher temperatures increase algal blooms
Exam tip: Essay questions often ask about impacts on societies. Structure your answer by sector: food, water, health, infrastructure, economy.
Health, infrastructure and displacement
Big idea: Climate change affects human health directly (heat, disasters) and indirectly (disease, nutrition). It also threatens infrastructure and may force millions to relocate.
Health impacts
- Heat-related illness: Heatstroke, dehydration, cardiovascular stress
- Vector-borne diseases: Malaria, dengue expanding to new areas
- Waterborne diseases: Flooding spreads cholera, typhoid
- Air quality: Higher temperatures increase ground-level ozone; wildfire smoke
- Malnutrition: Reduced crop yields affect food availability
- Mental health: Climate anxiety, trauma from disasters, displacement stress
Infrastructure and displacement
- Coastal flooding: Threatens ports, cities, roads in low-lying areas
- Permafrost thaw: Damages buildings, roads, pipelines in Arctic regions
- Storm damage: More intense hurricanes/cyclones destroy infrastructure
- Climate refugees: People forced to move due to sea level rise, drought, or disasters
- Economic costs: Damage repair, lost productivity, insurance costs
Climate justice issue: Those who contributed least to climate change (LEDCs, small island nations) often face the worst impacts and have the fewest resources to adapt.
Exam tip: In discuss or evaluate questions, consider who is affected and discuss equity issues.
Know your predicted grade
Take timed mock exams and get detailed feedback on every answer. See exactly where you're losing marks.
Try Mock Exams Free7-day free trial • No card required
IB-style question — climate impacts on people [3]
A low-lying coastal country is preparing for the effects of climate change. Outline three ways climate change could affect its human population. [3]
How to answer it, step by step
- Pick different human systems
• Sea-level rise floods homes and displaces people (climate refugees)
• Saltwater ruins farmland, lowering food production - Vary the system you choose
• More storms/heatwaves damage infrastructure and harm health
• Or: damage to fishing/tourism hits the economy
Final answer
Spread your three points across different human systems (food, health, economy) — not three kinds of flooding.
IB-style question — to what extent are impacts shared equally [4]
"Climate change harms all countries equally." To what extent do you agree with this statement? [4]
How to answer it, step by step
- Some impacts are global
• Warming, sea-level rise and extreme weather reach every country
• No nation fully escapes the changing climate - Vulnerability differs — reach a verdict
• Poorer/low-lying nations are hit hardest yet emit least; rich nations can adapt
• So harm is not shared equally — impacts are real for all but unevenly felt
Final answer
For 'to what extent', give both sides and a clear judgement — a one-sided answer caps your marks.