This deep dive covers Deep Dive: Why CO₂ is Increasing within Carbon Cycle for GCSE Biology. Topic 3: Carbon Cycle It is section 4 of 11 in this topic. Use this deep dive to connect the idea to the wider topic before moving on to questions and flashcards.
🔬 Deep Dive: Why CO₂ is Increasing
Atmospheric CO₂ has increased by 50% since pre-industrial times (280 → 420 ppm). Why?
- Burning fossil fuels — releases carbon stored for millions of years
- Deforestation — fewer trees to absorb CO₂ + burning releases more
- Draining peat bogs — exposes peat to oxygen, speeding decomposition
This extra CO₂ strengthens the greenhouse effect → global warming → climate change!
Practice questions for Carbon Cycle
Which process removes CO₂ from the atmosphere?
Explain how decomposers return carbon to the atmosphere.
Quick recall flashcards
How does decomposition return carbon to the atmosphere?
Decomposers (bacteria and fungi) break down dead organisms.
They respire, releasing CO₂ back into the atmosphere.
Without decomposers, carbon would be locked in dead material forever.
What does the carbon cycle do?
The carbon cycle continuously moves carbon between the atmosphere (as CO₂), living organisms, the soil, and fossil fuels.
Carbon is never created or destroyed — it is recycled.