How is carbon returned back into the atmosphere?

Carbon is returned to the atmosphere primarily through processes such as respiration, decomposition, and combustion. During respiration, animals and plants release carbon dioxide (CO2) as they convert glucose and oxygen into energy. Decomposition of organic matter by microbes also releases CO2 as they break down dead plants and animals. Additionally, the burning of fossil fuels and biomass for energy contributes significantly to the release of carbon back into the atmosphere.