Carbon is one of the most common elements found in living organisms. Chains of carbon molecules form the backbones of many organic molecules, such as carbohydrates, proteins, and lipids. Carbon is constantly cycling between living organisms and the atmosphere. The cycling of carbon occurs through the carbon cycle.
We breathe out carbon dioxide. This carbon dioxide is generated through the process of cellular respiration, which has the reverse chemical reaction as photosynthesis. That means when our cells burn food (glucose) for energy, carbon dioxide is released.
There is more carbon dioxide entering the atmosphere than is coming out of it. Carbon dioxide is known as a greenhouse gas, since it lets in light energy but does not let heat escape, much like the panes of a greenhouse. The increase of greenhouse gasses in the atmosphere is contributing to a global rise in Earth’s temperature, known as global warming or global climate change.
During the carbon cycle, animals and plants add carbon dioxide to the atmosphere through cellular respiration, and plants remove carbon dioxide through photosynthesis.
The burning of fossil fuels releases more carbon dioxide into the atmosphere, contributing to global warming.