There are people who don't believe that human beings are causing any global warming at all. Some people refer to them as "global warming deniers." No amount of persuasion or browbeating will change the mind of these so-called global warming deniers. As far as they're concerned, there isn't any conclusive evidence that it's real, or it's a hoax.
There's actually a plausible reason for why these individuals won't believe that global warming is happening, or that humans are causing global warming to happen. The rationale is that there's no way to know for certain that the
evidence that shows that global warming is happening isn't being
tampered with or manipulated to personally benefit someone, somehow. This should not be ignored or dismissed, because it's the same kind of argument that's used against scientists who argue that there is no conclusive evidence of global
warming or that humans are the cause of global warming. This conflict-of-interest controversy goes both ways.
The next question that might come to someone's mind is how to get around this dilemma. As long as we live in a society based on trade and money, there is practically no way to resolve it. We would all have to become experts on climate science, make direct observations ourselves, and come to a conclusion on global warming and the role that humans play in causing global warming. The problem is that this isn't a feasible solution.
The only other option that I can think of is to eliminate the conflict of interest itself. Fortunately there might be a way to do this; but right now it's not possible, and no one knows when (if ever) it will become possible. In order to eliminate the conflict of interest, we're going to have to transition to a post-scarcity society. There's a bonus to transitioning to a post-scarcity society when it comes to the issue of anthropogenic global warming, which is that in such a society we will be able to better manage, more efficiently improve, and even eliminate the need for some of the activities that are responsible for producing pollution in general.