Scientists understood the climate 150 years ago better than the EPA head today

The current head of the US Environmental Protection Agency Scott Pruitt does not believe or understand long-known principles of climate science and basic physics. Recently he claimed on CNBC that carbon dioxide is not a primary contributor to global warming:

"I think that measuring with precision human activity on the climate is something very challenging to do, and there’s tremendous disagreement about the degree of impact. So, no, I would not agree that’s a primary contributor to the global warming that we see. But we don’t know that yet. We need to continue the debate and continue the review and the analysis.'

There are two undeniable ironies in this statement....
https://www.theguardian.com/environment/climate-consensus-97-per-cent/2017/mar/31/scientists-understood-the-climate-150-years-ago-better-than-the-epa-head-today