While environmentalists were busy applauding the decline in carbon emissions in the wake of pandemic-induced lockdown in most parts of the world, the Mauna Loa Observatory in the US posted a peak of 417 parts per million of atmospheric CO2 for several days in early 2021. The only time carbon levels exceeded 400 parts per million before this was during the Pliocene era—four million years ago when the average surface temperature was warmer and sea levels were 33-82 feet higher than now—long before man’s entry on the scene.
