Carbon Dioxide Passes 400 PPM Milestone, NOAA Finds

Carbon Dioxide Passes 400 PPM Milestone, NOAA Finds (via Climate Central)

By Andrew Freedman Follow @afreedma 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…