Environment Report series on coal - Part 5 COLUMBUS, OH (WCBE) - Carbon dioxide emissions that cause global warming are driving power companies to a decision. They can move away from burning coal altogether...or they can work on technology to eliminate their C-O-2 emissions...someday. While they're making that decision, some of the nation's oldest, dirtiest coal-burning power plants still run. In the final part of our series on the future of coal, Shawn Allee looks at why they billow dangerous air pollution...stuff most people think we cleaned up long ago. © Copyright 2012, WCBE