Atmospheric CO2 levels just hit a scary new milestone

Scientists in the United States have detected the highest levels of planet-warming carbon dioxide in Earth's atmosphere since records began, sounding new alarm over the relentless rise of man-made greenhouse gas emissions. The Mauna Loa Observatory in Hawaii, which has tracked atmospheric CO2 levels since the late 1950s, on Saturday morning detected 415.26 parts per million (ppm). It was also the first time on record that the observatory measured a daily baseline above 415 ppm.