UK Progressive: In May 2013, the carbon dioxide monitoring station at Mauna Loa, Hawaii, recorded a major milestone the concentration of atmospheric carbon dioxide had crossed the symbolic red line of 400 parts per million for the first time since record-keeping began. Now, three years and several record-breaking months later, the last station on Earth without a 400 ppm reading has finally reached it. In a statement released Wednesday, the National Oceanic and Atmospheric Administration (NOAA) revealed that,...