• Honest skeptics (ordinary folks who genuinely and sincerely don’t understand the science, and raise questions accordingly)
• Independent deniers (ordinary people who just don’t understand the science, and choose to be very noisy about their ignorance)
• Astroturfers, as described by George Monbiot (these are apparently ordinary members of the public, in fact paid by PR companies to swamp websites with misinformation and inaccuracies, they hide behind anonymity and post furiously in comment threads, and only on climate change issues)
• Media deniers (Fox News, even though Rupert Murdoch himself is not a denialist; Melanie Philips, etc)
• Scientific deniers (almost invariably, denialist scientists are not climate scientists; some are no doubt paid to be sceptical, and others are sincere; the overwhelming majority of working climate scientists do not doubt the fundamentals of human-induced climate change science)
• Proxy interests (Think tanks: Cato Institute, Heartland Institute, George C. Marshall Institute, Senator James Imhoffe, etc)
• Industry associations (American Chamber of Commerce, American Petroleum Institute)
• Vested interests (Big oil, big coal: the likes of Exxon Mobil, BP, Shell, and possibly the Russian intelligence services)

More, here: Lepageblog