Final answer:
Carbon dioxide is emitted into the atmosphere via cellular respiration by living organisms and the burning of fossil fuels. It is removed by photosynthesis in plants and dissolution in ocean waters. Human activities, including deforestation and industrial processes, have disrupted the natural balance, increasing atmospheric CO₂ levels and contributing to climate change.
Step-by-step explanation:
Carbon is added to the atmosphere primarily through the processes of cellular respiration and the burning of fossil fuels. Organisms, including humans, release carbon dioxide during cellular respiration as they convert food into energy. The combustion of fossil fuels, such as coal, oil, and natural gas, for energy and transportation represents a substantial contribution to atmospheric carbon dioxide levels. Deforestation also plays a role, as it reduces the number of trees available to absorb carbon dioxide.
Conversely, carbon is removed from the atmosphere through photosynthesis, wherein plants convert carbon dioxide and water into glucose and oxygen, using energy from sunlight. This process not only supports the growth of plants but also helps mitigate the effects of carbon in the atmosphere by storing it in plant tissues. Oceans also act as carbon sinks, absorbing carbon dioxide from the atmosphere. When ocean waters cool, they can dissolve more carbon dioxide, which is then used by marine life or can form carbonate minerals on the seafloor.
Additional mechanisms of carbon exchange include the release of carbon dioxide from the decomposition of organic matter, geological activities like volcanic eruptions, and anthropogenic sources such as the production of cement. Each of these processes contributes to the dynamic balance of carbon between the atmosphere and the biosphere, but human activities have been shifting this balance, leading to increased atmospheric carbon dioxide levels and contributing to climate change.