The world is on fire, and not just from forest fires or...

The world is on fire, and not just from forest fires or volcanoes. Across the globe hundreds of fires burn low and slow on dirty fuel beneath the earth, smoldering for decades or even centuries.These fires are known as coal seam fires. They occur underground when a layer of coal in the earth’s crust is ignited. Due to the out-of-sight nature of the fires, they are often hard to detect at first, and even harder to extinguish. At any given moment there are hundreds of coal seam fires burning anywhere large coal deposits exist, from Pennsylvania to China to Germany. Due to their virtually endless supply of fuel and oxygen, many coal seam fires are expected to keep burning well into the next century.