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Chimie

Secondaire 4 • 6 juin 2025

I am in Secondary 4 and studying for the ST exam, but I am confused about something in the carbon cycle: I know that deforestation is a disruption in the carbon cycle and reduces the flow of carbon from the atmosphere to the biosphere, but how does a larger quantity of carbon dioxide remain in the atmosphere if its being reduced?

Explication (1)

Explication d’Alloprof

6 juin 2025

Hi ZombieLambda2833,
Thank you for your question :)
If we examine the interaction between trees and the atmosphere in the carbon cycle, we can see that there are two main processes at play: photosynthesis and respiration. At first, these two processes might seem like they cancel each other out, but in reality, a healthy tree absorbs more CO₂ than it releases. So, deforestation reduces the number of trees that can absorb and store CO₂, which disrupts the balance of the cycle. On top of that, when trees are cut down, they often decompose or are burned, which releases the carbon they had stored back into the atmosphere. That adds even more CO₂ to the air.
Here is a page that can help you with this concept: https://www.alloprof.qc.ca/en/students/vl/sciences/carbon-cycle-s1335
Don’t hesitate if you have any more questions :)
Sandrine