What is the primary effect of deforestation on the carbon cycle?

• A. It releases stored carbon and reduces the land's capacity to absorb CO2, increasing atmospheric CO2.
• B. It increases soil carbon sequestration.
• C. It decreases atmospheric CO2 concentration.
• D. It has no effect on the carbon cycle.

Answer: (A)

Deforestation primarily shifts the carbon cycle by turning a large carbon sink into a carbon source. Forests store carbon in both living biomass and soils; when trees are cleared or burned, that stored carbon is released back into the atmosphere as CO2. At the same time, removing trees reduces the land’s capacity to remove CO2 through photosynthesis, since fewer leaves mean less uptake of atmospheric carbon. The combination of increased emissions from the cleared wood and debris and decreased ongoing uptake from reduced forest area leads to higher atmospheric CO2 levels overall. Some carbon may be re-accumulated if regrowth occurs, but the immediate and net effect of deforestation is an increase in atmospheric CO2.