https://www.scientificamerican.com/article/we-just-breached-the-410-ppm-threshold-for-co2/
"The world just passed another round-numbered climate milestone. Scientists predicted it would happen this year and lo and behold, it has. On Tuesday, the Mauna Loa Observatory recorded its first-ever carbon dioxide reading in excess of 410 parts per million (it was 410.28 ppm in case you want the full deal). Carbon dioxide hasn’t reached that height in millions of years. It’s a new atmosphere that humanity will have to contend with, one that’s trapping more heat and causing the climate to change at a quickening rate."
