The United States is the biggest contributor to global warming, according to new research by a University of Maryland researcher.
But a mining company could have been the biggest carbon sink, said a study published in the journal Nature Climate Change.
Researchers analyzed emissions from mines in the United States and Canada and calculated that each ton of carbon emitted by the United Mine Workers Association is equivalent to about a million tons of carbon dioxide released into the atmosphere.
The UMWA is an organized labor union representing thousands of American mining and logging companies.
Its members have to pay $7.50 an hour and work a 12-hour day, and some workers have been forced to join the union to avoid being fired.
The UMWAs largest mine in Kentucky is located in Custer, Kentucky.
The mine emits nearly 50 percent of UMWAA emissions.
Researchers from the University of Washington, with funding from the U.S. Geological Survey, analyzed data from coal-fired power plants and power stations in the U