Skeptic is the wrong word, being skeptical is a component of critical thinking. Climate deniers are engaged in denialism. Other examples are flat earthers, and

Skeptic is the wrong word, being skeptical is a component of critical thinking. Climate deniers are engaged in denialism. Other examples are flat earthers, and alt-right. They're not exploring alternatives critically, they're attached to the rejection of established reasoning for no discernible reason, and it's the opposite of critical thinking, a rejection of epistemology. There is a distinction between "belief in" things that are not falsifiable, such as religious beliefs; and "belief that" which is knowable and evidence based. And denialists conflate these things, and become emotionally attached to belief in rejection of facts. So they spend a lot of brain cycles on myriad conspiracy theories to deny the conventional wisdom. What they claim to believe in as an alternative is more of a "by default" position rather than a sincere belief. e.g. if you ask flat earthers if they really think a person falls off the disk if they walk to the edge of the earth, or if there really is a giant wall of ice that mankind has never figured out how to climb, if we've never really been able to find out what's on the other side of the flat earth, they totally get stuck. They spend way way more time trying to disprove the convention, than the prove their position. It's a negative position, not one of advocacy. It is denialism.