CO2 in Earth's atmosphere nearing levels of 15m years ago

Last time CO2 was at similar level temperatures were 3C to 4C hotter and sea levels were 20 metres higher

The amount of carbon dioxide in the Earth's atmosphere is approaching a level not seen in 15m years and perhaps never previously experienced by a hominoid, according to the authors of a study.

At pre-lockdown rates of increase, within five years atmospheric CO2 will pass 427 parts per million, which was the probable peak of the mid-Pliocene warming period 3.3m years ago, when temperatures were 3C to 4C hotter and sea levels were 20 metres higher than today.