Please Stop Talking About the Global Warming Consensus

Here’s a thought provoking blog entry by George Musser over at Scientific American:

Last year, I started a thread on this blog to discuss doubts about global warming and humanity’s role in it. I tried to catalog the misgivings in as even-handed as way as possible and conducted a simple poll to see which broad category of doubts people found most persuasive. The top two results were:

• II. The present warming could be a natural uptick.
• VII. People who argue that human activity causes global warming cannot be trusted.

I offered a partial reply to the first of these last year. To summarize: different influences on the climate produce distinct patterns — for example, of spatial variation in temperature — and the observed patterns match what greenhouse gases should produce. They do not match what intrinsic climate variability or other natural causes would bring about.

But the climate debate that my colleague Dave Biello and I went to last night reminded me that the second of these concerns is still very much alive. Most of the arguments raised by the debaters and by audience members seemed to stem from the feeling that climate scientists and activists are haughty, sanctimonious, and hypocritical.

Like the climate itself, this is a very complex issue, having to do with attitudes toward intellectuals in our society and the way scientific findings can enter a meat grinder of politics and ideology. Let me bite off just one piece: what I see as overuse of the term “scientific consensus.”

When scientists use this term, they mean it to say that certain scientific questions have been settled to most people’s satisfaction and that it’s time to move on to other questions. But when non-scientists see this term, it sounds like a case of groupthink.

There’s no doubt that the term is useful. A consensus view in any field of science represents humanity’s best guess as to what’s going on. The guess might well be wrong, but what else is there to go on? It’s not as though there are answers in the back of the book to look at. People often say that science isn’t a democracy; scientific questions aren’t decided by majority rule. Well, then, what are they decided by? Experiments and observations, surely. But who runs the experiments and makes the observations? Who interprets the outcome? Who double-checks them? It is a social process.

If as a scientist I disagree with the consensus, I have to be very sure of myself to put my own judgment up against the collective wisdom. And if there’s one thing scientists learn very early in their careers, it is that such supreme self-confidence is usually misplaced. Nearly all scientists have painful memories of being pounced on in an oral exam for giving a sketchy answer, or presenting a paper before hundreds of people that turned out to be dead wrong. Most experts in a field realize that the more you know, the more you realize you don’t know. They learn to doubt their own judgment. If I get one answer and everyone else gets a different one, my first inclination should be that I’m wrong, not that everyone else is.

Sometimes, the individual is right and the community is wrong. It happens in times of scientific revolution, which by definition involve the overturning of a consensus view. But such revolutions are rare. We remember Einstein because he was unusual. Climate science shows no signs of being in a revolutionary phase. Evidence for anthropogenic warming is getting stronger with time. Discrepancies are diminishing rather than increasing. Technically, scientists are correct to assert that their field has reached consensus.

So the invocations of consensus are seen, by scientists, as expressions of humility. Yet the general public sees them as expressions of arrogance. To the man in the street, all the talk about scientific consensus sounds like: “Trust us, folks. Don’t worry your pretty little heads about it. Just think what we tell you to think.”

That rubs Americans, in particular, the wrong way. America wouldn’t be America without its suspicion of establishments of every kind. Hollywood valorizes the lone outsider fighting the powers than be. I think this romantic view is a healthy part of our country’s culture — it’s a safeguard against tyranny and an incentive for individuals to get involved in public life. But scientists can find themselves on the wrong side of the stick. They may see themselves as lone outsiders, but much of the rest of the country sees them as part of the machine. The British, for their part, really get off on puncturing pretentiousness — god help you if you walk into a pub and act full of yourself, as many climate scientists do.

The term “scientific consensus” is counterproductive in other ways, too. It sounds like asking people to take things on faith, which is contrary to the whole point of science. It also lets skeptical scientists claim they are being muzzled. They can argue that they are estranged from mainstream science for what they say, when in fact the problem is how they say it — their incomplete arguments or their unwillingness to apply the same skepticism to their own results that they apply to others’. Talking about consensus shifts the responsibility for their estrangement from them to the faceless wall of the powers that be.

So while I think there’s a role for mentioning scientific consensus, it should be used very sparingly. Telling people that there is a consensus cannot substitute for explaining why there is a consensus. As much as climate scientists may be wearying of debate, they need to press onward and treat each question as though it was the first time they had ever heard it.