For anyone who wants to dig further on this, http://ponce.sdsu.edu/global_warming_science.html explains the actual reasoning of the paper that came closest, which was an 1896 paper that laid out all of the actual facts behind global warming, minus the prediction that a rapid increase in usage of fossil fuels actually WOULD cause global warming. The author of that paper did come to the correct conclusion not long after, but I'm not aware of any record of his doing so before the year 1900.