How does the author describe the speakers at the Heartland Institute’s Sixth International Conference on Climate Change in June 2011 as noted in the nonfiction book, This Changes Everything?

Klein described Heartland as a right-wing think tank that opposes taking climate action; many members, in fact, are non-believers and think that the entire climate control matter is a hoax. Klein notes that one speaker at the conference offered the possibility that the movement was a Trojan horse to sabotage democracy with the establishment of Marxist socioeconomic doctrine.