Volcanic plume from Soufriere Hills on Montserrat, see from the ISS on October 11, 2009. Image: NASA.

Carbon dioxide! Little did we realize 100 years ago how this simple gas would become such a cultural lightning rod. Yet, here we are, battling what might be an existential fight that is focused on how much carbon dioxide humans pump into Earth’s atmosphere. It isn’t a little bit, either. No, humans might be now be the gold standard in carbon dioxide emissions in the history of the planet.