Which of the following best describes one effect of deforestation on the carbon cycle?

• A. Deforestation reduces carbon sequestration and releases stored carbon as CO2; less vegetation also lowers evapotranspiration and can alter albedo and local climate.
• B. Deforestation increases carbon storage in soils and reduces atmospheric CO2.
• C. Deforestation mostly affects soil nutrients with no climate impact.
• D. Deforestation only affects biodiversity, not the carbon cycle.

Answer: (A)

Deforestation disrupts how carbon moves between living things, the atmosphere, and the land surface. Forests act as major carbon sinks because trees and soil store large amounts of carbon and continuously remove CO2 from the air through photosynthesis. When forests are cleared or burned, that stored carbon is released back into the atmosphere as CO2 (and sometimes methane), while the removal of trees reduces the ongoing uptake of CO2. Disturbing the soil during clearing also exposes soil organic carbon to oxidation, further increasing atmospheric CO2.

Less vegetation means less evapotranspiration, so there is less water vapor added to the air and weaker latent heat transfer. This can reduce local rainfall and alter the local climate. The change in surface cover can also change albedo; bare ground or crops often reflects more sunlight than a dark forest, which can affect the energy balance locally. Taken together, deforestation lowers carbon sequestration and increases atmospheric carbon, with knock-on effects on local climate and hydrology.