Thousands of underground coal fires are burning out of control, oozing greenhouse gases through cracks in the ground.
Right now, thousands of coal fires are burning out of control around the world. The fires are heaving untold amounts of mercury, the greenhouse gas carbon dioxide (CO2) and other pollutants into the air.
The fires are notoriously hard to monitor; they tend to start at the surface but quickly scurry underground, only to ooze gases through soil and cracks in the ground. But an ambitious new study is now taking the first steps toward tallying their contribution to air pollution around the world.
Earlier this year, Allan Kolker of the United States Geological Survey in Reston, Va. and a team of scientists traveled to the Powder River Basin, a coal-rich region straddling the Wyoming-Montana border where dozens of fires are burning.
Using ground-based measurements, the team found that the Welch Ranch Fire emitted about 12 tons of CO2, and about 270 milligrams of mercury per day.
That's not much, but it's just one fire. Measuring the perhaps tens of thousands of coal blazes active in the world will be an arduous process, but the team hopes to speed things up by developing a method to fly over fires in an airplane and measure heat using an infrared camera. Carbon dioxide and mercury emissions should relate to temperature, which would allow researchers to calculate emissions from a fly-by.