Scientific American: A drop in U.S. carbon dioxide pollution in recent years stems from burning natural gas instead of coal. Or does it? Given that the U.S. bid to combat climate change through actions like the Clean Power Plan relies on more burning of gas than coal in power plants, that answer is both politically and scientifically important.
Compared with coal, burning natural gas results in roughly half the amount of CO2 per megawatt-hour of electricity. Yet even half the CO2, when spread over hundreds of power...