The chain of causation from fossil fuel burning to climate change is well understood:
- Burning fossil fuels releases CO₂ that has been stored underground for millions of years
- Atmospheric CO₂ concentration rises (from 280 ppm pre-industrial to 420+ ppm today)
- Higher CO₂ concentration means more infrared radiation is absorbed by the atmosphere
- More infrared is re-emitted back towards Earth's surface
- Earth's surface temperature rises — the enhanced greenhouse effect
- Warmer oceans evaporate more water vapour (another greenhouse gas) — this acts as a positive feedback, amplifying the initial warming
- Melting ice reduces Earth's albedo (reflectivity): darker ocean surface absorbs more radiation than white ice — another positive feedback
These feedback mechanisms mean that even a modest initial increase in CO₂ can lead to a much larger total warming effect. This is why scientists are concerned about "tipping points" — thresholds beyond which feedbacks become self-sustaining.
This how it works covers How Increased CO₂ Drives Climate Change within Climate Change for GCSE Chemistry. Revise Climate Change in Atmosphere for GCSE Chemistry with 20 exam-style questions and 15 flashcards. This topic appears regularly enough that it should still be part of a steady revision cycle. It is section 6 of 17 in this topic. Use this how it works to connect the idea to the wider topic before moving on to questions and flashcards.
Practice questions for Climate Change
Which statement correctly describes the difference between weather and climate?
Explain three consequences of climate change for the environment or human populations. [3 marks]