AtmosphereTopic Summary
Topic Summary: The Greenhouse Effect
Part of Greenhouse Effect — GCSE Chemistry
This topic summary covers Topic Summary: The Greenhouse Effect within Greenhouse Effect for GCSE Chemistry. Revise Greenhouse Effect in Atmosphere for GCSE Chemistry with 20 exam-style questions and 12 flashcards. This topic appears less often, but it can still be a useful differentiator on mixed-topic papers. It is section 13 of 13 in this topic. Use this topic summary to connect the idea to the wider topic before moving on to questions and flashcards.
Topic position
Section 13 of 13
Practice
20 questions
Recall
12 flashcards
Topic Summary: The Greenhouse Effect
Greenhouse Gases
- Carbon dioxide (CO₂)
- Methane (CH₄)
- Water vapour (H₂O)
- N₂O (nitrous oxide)
- NOT N₂ or O₂
The Mechanism
- Short-wave solar radiation passes through atmosphere
- Earth's surface absorbs and warms
- Long-wave infrared emitted by surface
- Greenhouse gases absorb and re-emit IR
- Some IR returns to surface → warming
Natural vs Enhanced
- Natural: keeps Earth at +15°C (essential)
- Without it: -18°C (frozen)
- Enhanced: extra warming from human activities
- CO₂: 280 ppm → 420+ ppm (human era)
Sources of Greenhouse Gases
- CO₂: fossil fuels, deforestation, cement
- CH₄: cattle, rice paddies, landfill, gas leaks
- N₂O: fertilisers, agriculture
- H₂O: natural (feedback mechanism)