What is the difference between carbon sink and carbon source?

A carbon sink is a natural or artificial reservoir that absorbs and stores carbon dioxide from the atmosphere, helping to reduce greenhouse gas concentrations. Examples include forests, oceans, and soil. In contrast, a carbon source releases more carbon dioxide than it absorbs, contributing to increased atmospheric CO2 levels; common examples are fossil fuel combustion and deforestation. Essentially, carbon sinks help mitigate climate change, while carbon sources exacerbate it.