The simple carbon cycle can be broken down into three main processes: photosynthesis, respiration and combustion. These processes combine to recycle carbon in the atmosphere and synthesize new carbon sources.
Carbon is constantly moving through the atmosphere. Every living thing on Earth is comprised of a small percentage of carbon. The element can also be found in the air, ocean and throughout the Earth’s crust. To keep the carbon levels relatively equal throughout the entire Earth, carbon must constantly be cycled. The carbon cycle can start with plants. Plants utilize carbon dioxide from the atmosphere to undergo photosynthesis and make their own energy. The carbon from the atmosphere becomes a part of the plant, and when the plant dies it will decompose into the Earth. Decomposition of these dead plants creates fossil fuels such as oil and coal. These fuels can then be combusted to release carbon into the atmosphere. Once in the atmosphere, the carbon can bind to oxygen to form carbon dioxide, and plants can once again utilize the carbon dioxide for photosynthesis. Humans and animals also contribute to the carbon cycle through respiration. Each time mammals exhale, they release carbon dioxide into the atmosphere that can then be cycled into the air.