FILE – In this May, 29, 2012, file photo, a train hauling coal from an Arch Coal Inc. mine in the Powder River basin of Montana and Wyoming heads north out of downtown Seattle. A 10 percent reduction in carbon dioxide emissions will mean a decline of 180 million tons, or 18 percent, in U.S. coal production, according to Bernstein Research. That would hurt miners such as Peabody Energy, Alpha Natural Resources and Arch Coal. (AP Photo/Elaine Thompson, File)