What is the principal effect of deforestation on climate change?

Deforestation plays a significant role in climate change primarily because it reduces the capacity of forests to absorb carbon dioxide (CO2) from the atmosphere. Trees and plants naturally absorb CO2 during the process of photosynthesis, acting as carbon sinks. When forests are cut down, not only is this absorption capacity diminished, but the carbon stored in the trees is often released back into the atmosphere, especially if the wood is burned or decomposes. This contributes to higher CO2 levels, a major greenhouse gas that drives global warming.

The other options do not accurately represent the principal effect of deforestation on climate change. For instance, the notion that deforestation increases biodiversity is misleading; the removal of forests typically leads to habitat loss, resulting in decreased biodiversity. Similarly, while soil quality may be affected by various factors, deforestation often leads to soil degradation, rather than improvement. Lastly, deforestation does not decrease carbon dioxide levels; in fact, it has the opposite effect, as described. Thus, the answer highlighting the reduction of CO2 absorption capacity is the most aligned with the realities of how deforestation impacts climate dynamics.