The first time readings crossed 410 at all occurred on April 18, 2017, or just about a year ago. Carbon dioxide concentrations — whose “greenhouse gas effect” traps heat and drives climate change — were around 280 parts per million circa 1880, at the dawn of the industrial revolution. Planetary carbon dioxide levels have been this high or even higher in the planet’s history — but it has been a long time. And scientists are concerned that the rate of change now is far faster than what Earth has previously been used to. Even farther back, in the Miocene era between 14 million and 23 million years ago, carbon dioxide concentrations in the atmosphere are believed to have reached 500 parts per million.

Source: Washington Post May 03, 2018 17:49 UTC