One of the climate-related memes that has tended to induce yawns in yours truly over the years concerns the so-called "deficit model" of climate communication. This is the idea that on the subject of climate the public are at best ill-informed and at worst pig ignorant and that they need better information about climate change in order to bring them round to the idea that we need to tear down the economy and build the new socialist future together.
Or something like that.
I thought the idea had been largely debunked - certainly for a number of years almost everybody from the sci-comms community seems to have been poo-poohing the idea and studies have shown that the scientifically literate are slightly more sceptical of global warming than the norm. So I was surprised to read this draft paper by Jesse Shapiro of the Booth School of Business at the University of Chicago, which almost seems to want to resurrect the idea:
On most topics, competition among special interests is innocuous and may even benefit the voter. Because it is easier to affiliate an expert when experts are divided, there can be a separating equilibrium in which parties have affiliates only when experts are divided. In such an equilibrium, the journalist reports both sides of the issue only when the science is indeed uncertain, and the voter always chooses the optimal policy given the distribution of expert opinion.
On high-stakes topics with a high likelihood of expert consensus, competition among special interests leads to a breakdown of informative communication. High policy stakes mean that changing the voter’s beliefs is very valuable, so the parties want to affiliate an expert even when there is an opposing scientific consensus. A high likelihood of expert consensus similarly encourages investment by the parties, because when consensus is likely, the unchallenged opinion of a random expert conveys a lot of information to the voter. If the parties’ incentives are strong enough, then both parties have affiliates regardless of the distribution of expert opinion, the journalist’s report always says that the issue has two sides, and the voter learns nothing.
According to the model, then, persistent public ignorance on climate change arises because, not in spite of, the issue’s importance and its amenability to empirical science. Perversely, greater scientific ambiguity would help the public, by dampening special interests’ incentives to challenge expert opinion.
I'm struggling with several of the ideas here. Firstly the suggestion that climate change is "amenable to empirical science". Given that the climate is a coupled non-linear chaotic system, I'm not sure that amenable is the right word. And the idea that there is a high likelihood of expert consensus is certainly highly questionable. Yes, most people involved agree on the greenhouse effect, but that may only be 30% of of the total effect with which some people say we are threatened. We are almost completely ignorant of even the sign of some the components of the remaining 70%. The IPCC's estimates of climate sensitivity go from 1 to 6°C for Pete's sake! To say that there is a high likelihood of expert consensus here is preposterous.
The other thing to say is that Kahan has advanced the idea that the public are somewhat immune to the opinions of experts anyway because everyone engages in motivated reasoning. It's odd that Kahan's work isn't discussed in Shapiro's paper.
The paper is rather mathematical and it is clear that Shapiro has put a lot of work into it. It's too bad that he didn't scratch the surface of what the climate debate is all about before he put pen to paper.
(Shapiro is lecturing in London on Monday week if any readers are interested).