> The earth hasn't had those level of CO2 and methane (in the air) since the Eocene (~2000 CO2 ppm). It's hard to imagine industry and agriculture functioning i

> The earth hasn't had those level of CO2 and methane (in the air) since the Eocene (~2000 CO2 ppm). It's hard to imagine industry and agriculture functioning in that context. Not to mention our brains. Cognitive ability declines significantly as CO2 concentration rises.