Here's the thing. Suppose we lived on a planet where we had no way of knowing whether increased temperatures caused increased carbon dioxide concentrations or vice versa? How would we ever find out? - TL Winslow, World's #1 climate scientist, amateur by choice

https://www.quora.com/Heres-the-thing-Suppose-we-lived-on-a-planet-where-we-had-no-way-of-knowing-whether-increased-temperatures-caused-increased-carbon-dioxide-concentrations-or-vice-versa-How-would-we-ever-find-out/answer/TL-Winslow