Emissions by Uncontrolled Coal Fires

Thousands of self-ignited coal fires, naturally occurring coal fires, and coal fires resulting from human activities persist for decades in underground coal mines, coal waste piles, and un-mined coal beds. These uncontrolled coal fires occur in all coal-bearing parts of the world and pose multiple threats to the global environment due to emission of greenhouse gases (GHG) such as CO2, CO, CH4, and other toxic substances such as mercury (Hg). Estimates of the amount of coal that is involved globally range between 20 and 600 Mt sing simple calculations, the only published peer-reviewed estimate of CO2 and Hg emissions from coal-fires in the United States (U.S.) are between 14 to 290 Mt/yr and 0.1 to 11.5 t/yr, respectively. In comparison, the U.S. coal-fired power plant fleet -the largest known anthropogenic source of CO2 and Hg to the atmosphere in the U.S.- emits ~2.4 Gt, and ~45 t annually, respectively. This paper builds on these results and will present result of a first-of-a-kind U.S.-based field campaign combining airborne remote sensing using thermal infrared technique and ground based measurements as a first step to constraining and scaling-up the emission factors, nature and extent of coal-fire emissions of CO2 and Hg to a global scale, which will allow for these emission sources to be better accounted for in global atmospheric models.