The theory of CO2-induced climate change is older and better-established than Relativity. It was also considered completely disproved for fifty years, by multiple independent lines of evidence. Clearly something happened to change everyone's mind, and it would probably do you some good to know about that, but the point is, it's not like there's some contradictory line of evidence that has gone unexamined. We've been trying to disprove this theory for twelve decades, and the actual scientific controversy ended at latest in the early 90s. At this point, the list of observations which would invalidate AGW is both very short and very nonsensical.

I am not sure why you are discussing a film. I would caution you against assuming that most people, particularly in this forum, are deriving their knowledge from a single film, as opposed to peer-reviewed articles, textbooks, or the IPCC reports. Personally, I consider this topic to be fairly important, especially given that I grew up in Alaska: climate change is an undeniable feature of the landscape there. I would agree that a lack of high-quality information on this subject is a problem. This is a resource that I would recommend:

  The Discovery of Global Warming
  https://history.aip.org/climate/index.htm