by Judith Curry

An academic feud swirls around how best or even whether to express the scientific consensus around climate change.

I’ve written several previous posts about the Cook et al. paper Quantifying the consensus on anthropogenic global warming in the scientific literature. See my previous posts on the paper:

The paper went viral when President Obama tweeted about it, and I saw somewhere that the paper had been downloaded 200,000 times.

Yesterday, I was motivated to reread the Cook et al. paper by this article in the Scientific American How to Determine the Scientific Consensus on Global Warming. The article originates from E&E Greenwire Profile of an academic feud: What do 97% of scientists believe about climate change? Excerpts from the SciAm article:

Academic disputes are different from bar fights. The point of contention is a peer-reviewed study published last year [by John Cook and coauthors] . The scientists examined 4,014 abstracts on climate change and found 97.2 percent of the papers assumed humans play a role in global warming.

That statement quickly got boiled down in the popular media to a much simpler message: that 97 percent of scientists believe climate change is caused by humans.

Predictably, climate change skeptics challenged the study. Lately, the [paper’s authors] have been battling a rear guard attack from within the climate science community itself. Some social scientists, political scientists, climate change communicators question whether informing people of a scientific consensus serves any purpose.

Cook thinks that politicians are not acting because the public is not pressuring them enough. If people realize that the majority of scientists agree on human-caused climate change, they will absorb that knowledge like empty vessels and become more convinced of the threat, he said. They will then be more amenable to picking up their phones and calling their legislators.

And yet the chain of events Cook mentioned, where people hear of the scientific consensus and call their lawmakers, has not happened. In fact, consensus messaging over the past decade has not convinced any more or any fewer Americans to believe in global warming.

“There’s no point in doing scientific research if you are not looking to publicize it,” he said. “A part of what we were doing was closing that consensus gap, and the consensus gap is delaying climate action. We wanted it to have a tangible impact.”

The blowback began soon enough from the climate skeptic community. Soon after came challenges from the scientific community. Tol, the economics professor at the University of Sussex, was among the most vehement.

Tol dislikes, in principle, the idea of a consensus. After all, the point of science is to challenge accepted wisdom and refine it, a process that runs somewhat counter to the idea of a consensus.

“I’m a hopeless romantic for the Enlightenment: I’d rather convince people with arguments than with an appeal to authority or consensus,” Tol said via email.

“I expected the criticism from climate deniers because they’ve been attacking the consensus for 20 years,” Cook said. “I’m a bit disappointed that scientists who accept the consensus and who are trying to work towards climate action are criticizing this method of communication because the reason why we did it was based on a lot of social science research.”

Kahan of Yale University disagreed with Cook that people, even in the middle, will change their minds when exposed to consensus messaging. In fact, most people are already broadly aware of the scientific consensus on climate change, he said.

A new question arises: ‘So what?’ Even assuming the consensus message does work, it will not necessarily lead to climate action by policymakers, said Mike Hulme, professor of climate and culture at King’s College London.

JC reflections

What triggered me to read the Cook et al. paper again was this statement in the SciAm article:

The scientists examined 4,014 abstracts on climate change and found 97.2 percent of the papers assumed humans play a role in global warming.

That statement quickly got boiled down in the popular media to a much simpler message: that 97 percent of scientists believe climate change is caused by humans.

Assumed? This comes across rather differently than my interpretation of the paper. The main concluding statement is this:

Among papers expressing a position on AGW, an overwhelming percentage (97.2% based on self-ratings, 97.1% based on abstract ratings) endorses the scientific consensus on AGW.

In my mind, there is a pretty big difference between ‘assume’ and ‘endorse’. The SciAm article makes the Cook et al. paper come across more soberly and scholarly than it actually is. This paper is a prime example of motivated scientific reasoning. As far as I can tell, here is what Cook et al. measured:

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Apart from the Cook et al. paper itself, I think the SciAm article is interesting in terms of highlighting the dissent on this topic, and raising the question as to how best or even whether to express the scientific consensus around climate change. This is a pretty heretical statement (a welcome one, IMO). And kudos to Richard Tol for his statements about consensus.

I have written numerous posts and one published paper on the problems with trying to manufacture a scientific consensus around the complex, poorly understood topic of climate change, for the purpose of motivating ‘action’ via speaking consensus to power:

From my paper No consensus on consensus:

When applied to a wicked and/or messy problem, the ‘speaking consensus to power’ approach underexposes scientific uncertainties and dissent, making the chosen policy vulnerable to scientific errors; and it limits the political playing field in which players can present different policy perspectives.

The climate community has worked for more than 20 years to establish a scientific consensus on anthropogenic climate change. The IPCC consensus building process arguably played a useful role in the early synthesis of the scientific knowledge and in building political will to act. We have presented perspectives from multiple disciplines that support the inference that the scientific consensus seeking process used by the IPCC has had the unintended consequence of introducing biases into the both the science and related decision making processes, elevating the voices of scientists that dispute the consensus, and motivating actions by some consensus scientists and their supporters that have diminished the public’s trust in the IPCC.

And finally, how are academic disputes (about climate change) different from bar fights? Rather than throwing physical punches, the consensus defenders throw their punches with inane tweets using pejorative hashtags, e.g. #denier #antiscience

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