Perhaps one aspect is that people can see an eclipse. It happens in real-time in front of them. The knowledge they need is simple observation in the moment. Lots of science does not show up that way (nor do many other things). Climate change occurs over long periods of time. People cannot connect cause and effect for such things based on their own (limited) scientific knowledge and reliance on immediate observation.

Once some people question scientific information, claiming one individual's opinion is as good as anyone else's facts, it isn't hard to confuse everything and question what is and isn't "true" overall. Then people make up their own "truth" to match either what they want to be true or want to be false about someone else's "truth."

This isn't some new phenomenon. It was going on when I was in school decades ago. It has been the case over time that people in positions of authority have promoted the idea of "alternate truth" as valid to appeal to masses of people for political purposes. We still see arguments that the American Civil War was not primarily about the right to own slaves regardless of this being stated in the constitutions of all the Confederate States.

Another tactic for argument against facts is simple deflection through the "but what about..." challenge to simply change the subject of the discussion.