Scientists are sceptical and questioning by their very nature. They love to poke and prod everything to see if it withstands scrutiny. So when scientists agree this is a sign that a question was investigated thoroughly and based on the evidence scientists then have an answer they can agree on.

This makes a scientific consensus the biggest threat to the denial of any scientific fact. Hence you see the “there’s no consensus” mantra on subjects like evolution, GMO safety, and of course global warming and climate change. That’s why studies like Oreskes 2004, Doran 2009, Anderegg 2010, Cook 2013, and Verheggen 2014 are targets for climate science deniers:

Like Oreskes said spreading doubt is the most effective strategy a science denier has. As long as there is a gap between what scientists agree on and what the public thinks scientists agree on you’ll delay action. This tactic is why the tobacco industry successfully delayed action against the harmful effects of smoking for decades.

Recent social-science research shows that accepting the consensus on climate change is a gateway belief. No matter what someone’s political beliefs are they are more likely to support taking action to solve the problem when they’re aware of the expert consensus on human-caused global warming.

This is why the following points by Naomi Oreskes from her AGU 2014 Fall Meeting presentation From Disinformation to Wishful Thinking are so important:

1. Don’t debate skeptics:
   You cannot win a debate with someone who cannot be convinced. It also gives the impression that there’s a debate where there is none. This then also can create the impression that there’s controversy.
2. Don’t emphasize uncertainty
   Bit of a delicate point, as all science is uncertain to a certain extent. Discuss these uncertainties honesty and openly, but don’t focus on them. You need to focus on what we know.
3. Don’t play fetch:
   Just because a so-called sceptic makes a claim it doesn’t mean you need to go after it. Pick your battles and go after those that matter.

I’ve always agreed with these points as following them will help reducing the confusion about global warming. If only the misinformation spread by contrarians and pseudo-sceptics weren’t amplified by the media it would reduce this consensus gap.

That’s why I’m critical of anyone who actually debates pseudo-sceptics as this is in most cases counter-productive. When you’re debating a subject in front of a lay audience sounding correct and giving a good performance almost always matters more than accuracy and sound reasoning.

The only chance you have at winning such a debate is if your opponent messes up, like in the Ken Ham vs Bill Nye debate. But my stance on this shifted slightly when Scott Denning shared his story about engaging contrarians and pseudo-sceptics at Heartland Institute conferences:

His story reminded me of a point Ben Santer raised in his AGU Fall Meeting presentation After the storm: Lessons learned from the IPCC’s “discernible human influence” finding. In it he said that you should “Engage audiences who mistrust or deny scientific findings of a ‘discernible human influence’ on global climate. Give them pause for thought.”

At the time I only saw it as advice to selectively engage pseudo-sceptics to counter important pieces of misinformation. So that you give those that accept the consensus the information to counter the misinformation, in essence inoculating them against it. Plus it also helps if you break through the echo-chamber you often see among pseudo-sceptics . But keep in mind,  you don’t want to “play fetch” as Oreskes put it.

What Denning did is take this a step further and held a presentation and debate in front of a hostile audience. They vehemently reject any research that shows global warming is real and a threat, but are quite uncritical about research or opinions that state otherwise (misrepresenting research and articles is also common among pseudo-sceptics ).

This is also why what Denning did was so effective. There’s a ‘consensus’ among pseudo-sceptics that the science is wrong that says that humanity is changing the climate and that this is a threat. But this is ideologically motivated, not based on evidence. There’s no coherent case or argument among pseudo-sceptics , they’re all over the place with their ‘evidence’ and reasoning why this is the case.

Denning demonstrated  how easy it is to undermine the ‘consensus’ of pseudo-sceptics . Most of what you hear at Heartland Institute conferences is already on the Global Warming & Climate Change Myths page of Skeptical Science. Knowing how to answer those should be easy for any climate scientist.

But the most effective thing Denning did is highlighting how incoherent the arguments of pseudo-sceptics are. At one point during the debate Scott heard the following remark aimed at him from Fred Singer: “Well Scott we know that the CO₂ absorption lines are completely saturated and that adding CO₂ will not change the [infrared] absorption of the atmosphere.” Before Scott could even respond to this Spencer jumped in and said “Fred, no. That’s just not right. Our research, spectroscopy, is based on those lines and I can tell you that that’s not correct.”

Spencer certainly has his issues with making inflammatory remarks and strange positions on science subjects, but in this case the scientist in him won and he had to respond to something that was incorrect. This infighting is easy to trigger among pseudo-sceptics as their position is based on ideology and not evidence, so when evidence is discussed you get some very strange responses and conflicts. Which is in stark contrast to how scientists normally debate as they are led by the data and evidence they have. To quote John Reisman, “Science is not a democracy. It is a dictatorship. It is evidence that does the dictating.”

Engaging pseudo-sceptics like this is of course not for everyone, you need to know how to handle hostile audiences and how to debate in front of them. You also shouldn’t let it be more important than addressing larger audiences, after all these vocal pseudo-sceptics are just a small group no matter how loud they are. You also won’t convince most of them, but you can reach those that were misinformed because they were surrounded by pseudo-sceptics . These are the dozens of people who admitted to Denning that he had changed their minds.

Even though this is a small group it can be a battle worth fighting. There are multiple angles of attack you can use to introduce cracks into the ideological armour of pseudo-skeptics. And I’ll gladly support anyone who manages to do just that. Though in this case it’s even more fun to see what happens as Denning is introducing doubt among those that listened to the Merchants of Doubt.