Key Idea: Most marks in topic 7.3 come from waste disposal options and preventing waste rather than cleaning it up. There are no extra HL statements here, so learn the same content as SL.
1. Disposal options (most marks)
- Landfill: cheap, but uses land, leaks leachate and gives off methane.
- Incineration: cuts volume by about 90% and makes energy, but emits gases and ash.
- Recycling saves resources; composting turns food waste into soil. CopenHill burns waste for heat.
2. Prevent rather than clean up
- Preventing waste stops it being made; restoring cleans up after harm.
- Ireland's 2002 bag charge cut plastic bag use by over 90%.
- Kamikatsu, Japan, sorts waste into about 45 types and recycles about 80%.
3. How waste varies
- The world made 2.01 billion tonnes in 2016, heading for 3.40 billion by 2050.
- Richer societies make more waste and more dry waste: paper, plastic, metal, glass.
- Poorer societies throw away more food waste and dump most of it in the open.
How it is examined:
| Question | How to score |
|---|---|
| [1] to [2] Describe waste data | Direction, values and units; compare countries or years. |
| [2] Outline a disposal option | One advantage and one disadvantage, with a reason each. |
| [4] Explain why waste differs between societies | Income, lifestyle, packaging, then the effect. |
| [4] to [7] Evaluate a waste strategy | Strengths, limits, named example, judgement. |
| [9] Discuss prevention v cleaning up | Both sides with named examples, then a judgement. |
Key terms, one line each:
| Term | In one line |
|---|---|
| Solid domestic waste (SDW) | rubbish from homes: food, paper, plastic, glass, metal |
| Leachate | polluted liquid that drains out of a landfill |
| Incineration | burning waste, often to make electricity or heat |
| Waste hierarchy | reduce first, then reuse, recycle, recover energy, and landfill last |
| Circular economy | keeping materials in use by design, so little becomes waste |
Last-minute check: answer, then tap to see.
Which greenhouse gas comes from landfills? Methane, from food rotting without oxygen.
By how much does incineration cut waste volume? About 90%.
Is a plastic bag charge preventative or restorative? Preventative: fewer bags are made and used.
Why did waste exports change after 2018? China's National Sword policy banned most plastic imports.
Some towns aim for zero waste, while others spend money cleaning litter from rivers and beaches. Explain why preventing waste is more sustainable than cleaning it up.
Model answer plan
See the mark-by-mark plan — for / against / judgement, with marking guidance — in study mode.
Exam tips
- For a disposal option, give an advantage and a disadvantage with a reason.
- Say whether a strategy is preventative or restorative.
- Use named examples: Kamikatsu, Ireland's bag charge, CopenHill.
- Topic 7.3 is the same at SL and HL, so practise the [9] on prevention v clean-up.