A nonpartisan group called the Environmental Integrity Project analyzed that data further and found that 2007 showed a net increase in carbon dioxide emissions nationwide. The analysis also ranked Kentucky as one of 10 states emitting the most power plant CO2. Researchers found that emissions are up for a number of reasons, but mainly because of the nation’s increasing appetite for energy. Existing plants may be emitting more CO2 because they’re operating at higher capacity. New plants have come online and more are on the way. The report also cites US Department of Energy data that CO2 lingers in the atmosphere anywhere from 50 to 200 years. So even if all plants shut down right now, the carbon dioxide they’ve already emitted will be around for years to come.