They knew in 1912. 💀
[ http://www.snopes.com/1912-article-global-warming/ ]
1912 called
Said we told you 100 years ago
you are screwing with the climate with your coal.
the Snopes article is well worth reading. People were discussing this stuff back in 1896.
So it was known and yet…
105 years later, people are still shoving their fingers in their ears and screaming “NO I CAN’T HEAR YOU”