>>508800702
>Graph starts from 1960, with a ceiling of 440ppm
it's solid data straight atmospheric readings from an observatory at mouna loa everything else comes from ice and rocks
https://gml.noaa.gov/ccgg/trends/
you're also implying that human society could remain unchanged in a climate similar to the cambrian (even now we're just coming out of an ice age) which is silly
>>508801352
>>508800977
you seem miss-informed
most atmospheric oxygen is produced by oceanic plankton (plant are kinda shit at making oxygen)