In the sciences, denialism is the rejection of basic facts and concepts that are undisputed, well-supported parts of the scientific consensus on a subject, in favor of radical and controversial ideas.[3] The terms Holocaust denialism and AIDS denialism describe the denial of the facts and the reality of the subject matters,[4] and the term climate change denial describes denial of the scientific consensus that the climate change of planet Earth is a real and occurring event primarily caused by human activity.[5] The forms of denialism present the common feature of the person rejecting overwhelming evidence and the generation of political controversy with attempts to deny the existence of consensus.[6][7]