Which natural processes release carbon dioxide into the atmosphere?

Natural processes release carbon dioxide (CO₂) into the atmosphere as part of the global carbon cycle, maintaining a balance between sources and sinks. Key natural sources include:

• Volcanic Activity: Volcanoes release CO₂ through outgassing from magma. This occurs both during explosive eruptions and through fumaroles, which are volcanic gas vents that can leak CO₂ from underground magma chambers.123
• Respiration: Aerobic organisms, including plants and animals, release CO₂ as a waste product during respiration. This process involves the breakdown of organic fuel molecules to generate energy for life-sustaining activities.245
• Decomposition: As terrestrial vegetation and other organic matter die, they undergo natural decay. Microorganisms involved in this process break down the organic material, releasing the carbon that was previously sequestered in the organism's tissues back into the atmosphere.627
• Soil Respiration: Soils release CO₂ through the transformation of organic matter by soil microbes, a process known as soil respiration. This is a significant natural flux of carbon from the land surface to the atmosphere.7

These natural emissions are typically balanced by "sinks," such as photosynthesis in plants and oceanic processes, which remove CO₂ from the atmosphere.24