Coal and petroleum are two forms of carbon that are found naturally in the Lithosphere ( the solid part of the Earth that sits above the Mantle). Both coal and petroleum are considered natural resources and sources of energy, and both also originate from geologic transformation of organic material.
The burning of these forms of carbon release carbon dioxide into the atmosphere. Since it is a greenhouse gas, an increase in carbon dioxide also increases the ability of the atmosphere to retain heat. This is called the Greenhouse Effect.
