Natural gas is a naturally occurring hydrocarbon gas mixture consisting of methane and commonly also including varying amounts of other hydrocarbon gases, and sometimes a small percentage of carbon dioxide, nitrogen, hydrogen sulfide, and/or helium. Because it is colorless, odorless, and explosive, a sulfur odor is usually added for early detection of leaks.
Natural gas is formed when layers of decomposing organic matter are exposed to intense heat and pressure under the surface of the earth over millions of years. The chemical bonds in the gas molecules store the energy that the plants originally obtained from the sun.
Natural gas is widely used as a source of energy for heating, cooking, and electric power generation as well as for a fuel for vehicles and as a chemical feedstock in the manufacturing of plastics and other organic chemicals. Although it can create less waste and toxins at the point of use than other fossil and biomass fuels, its extraction and consumption can still result in a similar carbon footprint and are a major factor in climate change. This is because it is a potent greenhouse gas when released into the atmosphere, because it creates carbon dioxide when burned, because of gas venting and flaring during extraction, and because of unintended emissions throughout its distribution chain.