Just as it took us too long to arrive at common knowledge that smoking kills people, so we are taking too long to arrive at common knowledge that people kill the Earth. But why? Paid pundits, that’s why! Or, as Merchants of Doubt calls them, merchants of doubt. First this was a book by Naomi Oreskes and Erik M. Conway, who surely thought it a public service to pat down the deep pockets of disinformation. Now Food, Inc. director Robert Kenner has turned it into a redundant, formally uninventive, Food, Inc.-like documentary. This is at least well-timed, and maybe most useful as a swift, swallowable backgrounder on how snowballs wind up on the Senate floor. Kenner likens media savvy experts-for-hire to three-card monte shills who play and win to sucker you into thinking you can too. Including such charlatans among his talking heads, along with investigative journalists who gloatingly expose them, his presentation unwittingly underscores the unfortunate fact that these amoral pundits have more camera-ready charisma, albeit negative, than the average upstanding climate scientist. More problematically, Kenner fails to investigate, or even to address, the vast human capacity for being entertained by deception. It helps that his cast includes climate-change converts like Skeptic magazine editor Michael Shermer and former South Carolina Republican Rep. Bob Inglis — the latter owning up to “a legacy of people who failed to lead” and being the movie’s resident voice of reason. Only he seems sincerely interested in why deniers deny.