Climate Central: On May 9, the amount of carbon dioxide in the air exceeded 400 parts per million (ppm) for the first time in the observational record since 1958, and very likely for the first time in at least 800,000 years, the National Oceanic and Atmospheric Administration (NOAA) announced on Friday. This marks the first time the daily average CO2 concentration has risen past 400 ppm in the iconic record kept by the Mauna Loa Observatory in Hawaii, where daily observations go back to 1958,
Climate scientists...