It was compared to holding a hearing about whether “the Earth orbits the Sun”.

But the attempt by the Republican-controlled US House of Representatives’ Science Committee to challenge the science behind climate change appears to have, somewhat, backfired.

At the outset, Lamar Smith, who chairs the committee, made his views clear: the “alarmist theories” of climatologists had “no hard proof”, he claimed.

And anyone who even tried to predict what would happen to the Earth’s climate by 2100 was “not credible”.

One commentator suggested the "insane" hearing was a form of gaslighting, with the "cavalcade of falsehoods" designed to make people question their mental health.

Just one renowned climate scientist, Professor Michael Mann, appeared at the hearing, flanked by three academics described as being “very much in the minority” on the issue.

But one of them, Dr Roger Pielke, a climate science policy writer at Colorado University, clearly disappointed some committee members when he said climate science had consistently shown there was a “fundamental risk” since the 1980s.

He even advocated imposing a carbon tax on petrol to “raise billions” for climate-related projects.

That suggestion prompted a telling response from one Republican committee member, Randy Weber, who described it as “blasphemy”.

Professor Mann, whose work on the famous ‘hockey stick’ graph demonstrated the world has been getting unnaturally warm, told the hearing: “We find ourselves at this hearing today, with three individuals who represent that tiny minority that reject this consensus or downplay its significance, and only one – myself – who is in the mainstream.”

As someone who has received hate mail and death threats over his research, he spoke with passion about the anti-science campaign against climatologists in the US.

“The attacks against scientists by individuals and groups, many of which allied with fossil fuel interests and fossil fuel front groups, have a lot of goals. One of which is to silence researchers,” said Professor Mann, of Pennsylvania State University.

“If every time you publish something you are worried about having to respond to endless FOIA [Freedom of Information Act] requests and receiving thousands of emails and being called to testify, obviously that’s very stifling.

“The intention is to cause scientists to retreat. It’s meant to send a chilling signal to the entire research community.

“That is: if you, too, publish and speak out on the threat of human-caused climate change, we're going to come after you.”

He said Republicans had been “going after scientists simply because you don't like their publications of their research – not because the science is bad, but because you find the research inconvenient to the special interests who fund your campaigns”.

“I would hope we could all agree that is completely inappropriate,” Professor Mann said.

However a colleague at Pennsylvania State University suggested Professor Mann was being “the sucker at the climate hearing poker table” just by going to talk to the Science Committee – a startling indication of the gap between the politicians and scientists.

Professor David Titley, a retired US Navy admiral, wrote in The Washington Post ahead of the hearing: “This hearing, whose witnesses consist of one mainstream climate scientist and three other witnesses whose views are very much in the minority, is remarkably similar in structure and scope to the climate hearing Senator Ted Cruz conducted in December 2015 titled ‘Data or Dogma?’ So similar that two of the five witnesses from the Cruz hearing will also testify.

“In the past, the science community has participated in these hearings, even though questioning the basics of climate change is akin to holding a hearing to examine whether the Earth orbits the Sun. Enough!

“We should no longer be duped into playing along with this strategy.

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“A better response would be to simply boycott future hearings of this kind and to call out these hearings for what they are: a tactic to distract the public from a serious policy debate over how to manage both the short- and long-term risks of climate change.

“These hearings are designed to provide theatrics, question knowledge that has been well understood for more than 150 years, and leave the public with a false sense that significant uncertainty and contention exist within the science community on this issue.”

Professor Mann was at pains to thank leading Republicans like John McCain, James Baker and George Shultz for their support for the scientific evidence.

But Mr Smith appeared to speak for many of his fellow party members on the committee.

“Far too often, alarmist theories on climate science originate with scientists who operate outside the principles of the scientific method,” he said in his opening statement.

“The [scientific method] avoids speculation about distant events for which there is no hard proof.

“Alarmist predictions amount to nothing more than wild guesses.

“The ability to predict far into the future is impossible. Anyone stating they know what the climate will be in 500 years or even at the end of the century is not credible.

“All too often scientists ignore the basic tenets of science in order to justify their claims.

“Their ultimate goal is to promote a personal agenda, even if the evidence doesn't support it.”

Eddie Bernice Johnson, the ranking Democrat on the committee, expressed dismay.

“Even in this committee on science, Republican members have postulated unique theories about climate change,” he said.

“It saddens me really that the majority members of Congress and of this committee in particular, consistently ignore the thousands of scientists around the world who maintain mainstream science views and instead repeatedly call in a handful of preferred witnesses —who are here today — over and over again to testify.”

Noting that the consensus on climate change is supported by 97 per cent of scientists in the field, Suzanne Bonamici, another Democrat, pointed to the discrepancy on the panel.

“The witness panel does not really represent the vast majority of climate scientists,” she said. “We'd need 96 more Dr Manns.”

Commenting on the hearing, Rush Holt, chief executive of the American Association for the Advancement of Science, told AFP that Congress should try to speak to a broader range of scientists.

"There is much our nation can do to address the risks that climate change poses to human health and safety, but disregarding scientific evidence puts our communities in danger," he said.

In the past, he has compared disputing climate science to denying the theory of gravity.

Emily Atkin, writing in New Republic, suggested Republican climate sceptics had been emboldened by the presence of Donald Trump in the White House.

"House Republicans held an insane hearing just to attack climate science," she said.

"The Trump administration has been nothing if not a master class in gaslighting — the art of manipulating people, often through lies, into questioning their own sanity — and its pupils on Capitol Hill have clearly been taking notes.