Greenhouse gas emissions by the United States of Energy's Energy Information Administration (EIA). Electricity generation increased by 2.5%, and carbon dioxide emissions from the power sector increased even more, at 3%, indicating that U.S. utilities shifted towards energy sources that emitted more carbon. That shift was partially caused by a 40 billion kilowatt-hour decrease in hydropower production causing a greater reliance on fossil fuels like natural gas and coal. Carbon dioxide emissions from power plants fueled with natural gas increased by 10.5%, while coal-burning power plants increased their emissions by 1.8%. Paper is the fourth largest contributor to greenhouse gas emissions in the United States and one
Carbon in the Earth's atmosphere (approximately 810 gigatonnes of carbon) and dissolved in all water bodies (approximately 36,000 gigatonnes of carbon). Around 1,900 gigatonnes of carbon are present in the biosphere. Hydrocarbons (such as coal, petroleum, and natural gas) contain carbon as well. Coal "reserves" (not "resources") amount to around 900 gigatonnes with perhaps 18,000 Gt of resources. Oil reserves are around 150 gigatonnes. Proven sources of natural gas are about (containing about 105 gigatonnes of carbon), but studies estimate another of "unconventional" deposits such as shale gas, representing about 540 gigatonnes of carbon. Carbon is also found in methane hydrates