Who remembers that climate change was a top priority early in George W Bush’s first term as US president? Merchants of Doubt, a new documentary film released in US cinemas this week, reminds us that in June 2001 Bush and the Republican party were 100% committed to curbing carbon emissions causing global warming.

Six months later everything changed. The film shows Republican party leader John Boehner calling the idea of global warming “laughable”, said Merchants of Doubt director Robert Kenner.

With the 9/11 attacks on the World Trade Center occupying attention, Americans For Prosperity, a powerful, fossil-fuel lobby group founded by the billionaire Koch Brothers, launched a decade-long, multi-pronged campaign to sow doubt about the reality of climate change.

By equating the findings of climate scientists as an attack on personal freedoms, they cleverly shifted the focus away from science to political opinion. “Creating a focus point away from what is actually going on is how magicians pull off their tricks,” said Kenner who directed the Oscar-nominated documentary Food Inc.

The deception has worked well. Few Americans know 97% of scientists agree climate change is caused by human activity and is happening now.

Inspired by the 2010 book of the same name, Kenner’s film is about deception and profiles many of the charming and always smiling professional deceivers who work for the tobacco, chemical, pharmaceutical, and fossil fuel industries. The tobacco industry knowingly and successfully deceived the public for 50 years about the connection between smoking and cancer, the 1988 tobacco lawsuit settlement revealed.

In a pattern of manipulation clearly evident today in the manufactured ‘debate’ over climate change, the tobacco industry used media-friendly pseudo-experts, doctored ‘science’ studies and attacked the credibility of scientists or experts who said otherwise, Kenner said.

Peter Sparber, one the tobacco industry’s most successful deceivers, told Kenner that he could get the public to believe a garbage man knew more about science than prominent climate scientist James Hansen.

“If you can sell tobacco you can sell anything,” Sparber tells Kenner.

Selling confusion and doubt around a complex issue like climate change was far easier than selling tobacco. Nearly all of those well-paid climate misinformers have no science background and often clear ties to industry lobby groups and yet are treated as expert commentators on climate science by media. It’s not just Fox News. Serious news outlets like CNN and the New York Times are complicit by featuring misinformers in news articles and on discussion panels, he said.

The film also focuses on the many self-described “grassroots” organisations that are actually promoting specific corporate and political interests. These organisations are often aided by, and passionately supported by, ordinary citizens who believe they are fighting for personal freedoms and libertarian or conservative values.

Kenner is hoping audiences “will realise they’ve been lied to” and develop better “bullshit detectors”.