If we add up all of the carbon in carbonate rocks, we get an atmospheric pressure similar to Venus. Venus probably had water and a less dense atmosphere. Carbon dioxide and water vapour are very good infrared absorbers. Mechanisms which control these gases control atmospheric temperature. Rain from the clouds falls back to the ground, where the water then runs back into the oceans.
Carbon dioxide is controlled by the carbon cycle.
Carbon in the rocks is expelled by volcanoes in the form carbon dioxide. Rain dissolves atmospheric CO 2 and washes it into the ocean. Now, on the Earth, shelled animals use disolved carbon to make their shells. Green plants also take in CO 2 gas. When they die, some of this material gets buried and forms rocks like coal.