Hydrocarbon/ˌhaɪdrəˈkɑːrbən/ Definition 1 of 2Pro Tip 1/3Energy Source Hydrocarbons are important in daily life as major energy sources for transportation and heating. Hydrocarbons in gasoline power our cars. Pro Tip 2/3Environmental Impact Burning hydrocarbons contributes to air pollution and climate change. Reducing hydrocarbon use can lower carbon emissions. Pro Tip 3/3Variety of Forms Hydrocarbons vary from gases like methane to solid forms like coal. Natural gas is a gaseous hydrocarbon used for cooking.