The last time the planet saw upwards of 400 PPM CO2 was 20-60 million years ago. I am pretty sure such a change will ruffle a few feathers. https://en.wikiped

The last time the planet saw upwards of 400 PPM CO2 was 20-60 million years ago. I am pretty sure such a change will ruffle a few feathers. https://en.wikipedia.org/wiki/Paleocene%E2%80%93Eocene_Thermal_Maximum https://en.wikipedia.org/wiki/Paleocene%E2%80%93Eocene_Therm...