Sceptical of climate change or just sceptical of the solution?
Those denying the science are more likely just opposed to the remedies
It is often said that people who don't want to solve the problem of climate change reject the underlying science, and hence don't think there's any problem to solve. But consider a different possibility: because they reject the proposed solution, they dismiss the science. If this is right, our whole picture of the politics of climate change is off.
Here's an analogy. Say your doctor tells you that you must undergo a year of gruelling treatment for a serious illness. You might question the diagnosis and insist on getting a second opinion. But if the doctor says you can cure the same problem simply by taking a pill, you might just take the pill without asking further questions.
Troy Campbell and Aaron Kay of Duke University's business school call this phenomenon "solution aversion". And they have found compelling evidence for it in the context of climate change.
In the most important of several experiments, they presented a large number of participants, both Republicans and Democrats, with this description of the current science of climate change: "The Intergovernmental Panel on Climate Change reported that there would be an increase of 3.2 degrees Fahrenheit [1.8 degrees Celsius] in worldwide temperatures in the 21st century and that humans are responsible for global climate change patterns." This statement was placed alongside a recommendation that the US impose restrictive regulations to reduce greenhouse gas emissions. The researchers also presented a similar group of people with the same description of the science, but alongside a recommendation that the US profit by leading the world in green technology.
In both instances, Campbell and Kay asked the participants whether they agreed with the IPCC. And in both, about 80 per cent of Democrats did agree; the policy solutions made no difference.
Republicans, in contrast, were far more likely to agree with the IPCC when the proposed solution didn't involve regulatory restrictions. Given the prospect of regulation, only 17 per cent of Republicans agreed with the IPCC. Given the prospect of profit from green technology, however, 64 per cent of Republicans agreed.
Here, then, is powerful evidence that many people (of course not all) who purport to be sceptical about climate science are motivated by their hostility to costly regulation.
Liberals are hardly immune to solution aversion. Consider this question: should Americans be very worried about "intruder violence", committed by criminals who come into people's homes? You might think that the answer wouldn't depend on the respondent's attitude towards gun control. But it turns out that liberals express much more concern about intruder violence when they're told gun control would reduce such violence than when they're told gun control would increase it.
For decades, social psychologists have emphasised the pervasiveness of "motivated reasoning": if people really don't want to believe something, they will work hard to find a way not to believe it. People's willingness to believe a diagnosis often turns on the proposed treatment.
It follows that, for politics in general, it may not be enough for reformers to argue that society faces a serious problem. People will be more receptive to such a claim if the proposed solution is consistent with their deepest commitments. If any kind of bipartisan agreement is to emerge on the science of climate change, it will be because it can be demonstrated that efforts to reduce greenhouse gas emissions are broadly compatible with the operation of free markets - and high levels of economic growth.
Cass Sunstein is the Robert Walmsley University professor at Harvard Law School