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.
⚙️ How Increased CO₂ Drives Climate Change
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.
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]