419 parts per million.
— NOAA Research (@NOAAResearch) June 7, 2021
That's the 2021 peak for atmospheric carbon dioxide measured at NOAA’s Mauna Loa Atmospheric Baseline Observatory - the highest level in 63 years, according to scientists from NOAA, @Scripps_Ocean & @UCSanDiego. https://t.co/MrBh0UEHaY pic.twitter.com/xFbZElaCue