That's not really the question. We know the global climate is currently changing at an unusual rate, and with a specific warming trend. The question is whether or not that change is at least partially due to man-made causes. We call this "human-caused global climate change", and according to over 90% of the world's scientists, the Pentagon, and the U.S House of Representatives as of 3 weeks ago, no it's not fake at all. As far as those who claim that the evidence for human-caused climate change is insubstantial, most of them tend to have a economic or political reason for claiming that. This is not to say that some of those economic reasons aren't valid concerns, but claiming that a thing is fake simply because it doesn't suit a particular agenda is not only dishonest, it's also short-thinking, dangerous, and possibly catastrophic.