What is it
This topic covers the evolution of the Earth's atmosphere over geological time, the current composition of the atmosphere, human contributions to greenhouse gases and climate change, and atmospheric pollutants from fuel combustion.
Why it matters
This is GCSE chemistry's most directly real-world, current-affairs topic, and exam questions increasingly test the ability to evaluate evidence about climate change, not just recall facts.
Exam tip
Be ready to explain the greenhouse effect mechanism (short-wave radiation in, long-wave radiation trapped) in your own words — 'explain' questions on this topic expect the mechanism, not just naming 'CO₂ causes warming'.
Related topics
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