The combustion of coal, however, adds a significant amount of carbon dioxide to the atmosphere per unit of heat energy, more than does the combustion of other fossil fuels. (eia.gov)
Of course oil producers and other fossil fuel interests do not want to help the state transition away from their products and the harm they cause. (ucsusa.org)
Small - scale gold production and residential heating from other fossil fuels are other major sources. (scientificamerican.com)