Clearing forests tends to increase atmospheric CO2 and flood risk. Which option reflects this effect?

• A. Decreases CO2
• B. Increases CO2
• C. No effect
• D. Only affects biodiversity

Answer: (B)

Clearing forests changes the carbon balance: forests store a lot of carbon in trees, soils, and litter. When trees are cleared or burned, that stored carbon is released back into the atmosphere as CO2, and with fewer trees to absorb CO2 through photosynthesis, the area becomes less effective at taking CO2 out of the air. The combination of releasing carbon and reducing uptake leads to higher atmospheric CO2. The mention of flood risk is about another consequence of deforestation, but for the CO2 part the effect is an increase.