What are ways that carbon can enter the atmosphere?

Carbon can enter the atmosphere through several processes, primarily the combustion of fossil fuels such as coal, oil, and natural gas, which releases carbon dioxide (CO2) during energy production and transportation. Deforestation also contributes by reducing the number of trees that can absorb CO2, while decomposition of organic matter and respiration by plants and animals release carbon in the form of CO2 and methane (CH4). Additionally, volcanic eruptions can emit carbon dioxide and other greenhouse gases directly into the atmosphere.