Science communication is an evolving art, backed by some interesting research. However, my overall take on the state of the research is that it is mostly telling us the various ways in which we fail, rather than how to succeed. The latest target if scicomm handwringing is “consensus messaging.” How do we, and should we, communicate the scientific consensus to the public?

This issue is probably most salient to communication about global warming. Those who deny the scientific consensus on AGW frequently deny that there is a consensus and/or deny that a scientific consensus is even meaningful. How should we address this situation. In 2018 Russil argued that consensus messaging is generally ineffective. Instead we should focus on the victims of climate change:

“If we recognize that climate change danger will be mediated by questions of migration, dislocation and refuge, and if climate change communication abandons the legacy of consensus messaging to involve those affected by danger, how might our work unfold differently?”

It’s fine to try new approaches, but my problem with this argument is that essentially nothing works when it comes to changing minds on AGW, and so the fact that any one strategy does not work doesn’t really tell us anything about that strategy, or favor any other.

The concept of consensus does, in fact, exist in science. I wrote about it previously here and here. If the vast majority of scientists agree on some scientific conclusion, that is a consensus. That much is historically undeniable, so the strategy is often to switch to the position that a consensus is meaningless. That’s not how science works. To bolster this position often an example of when a scientific consensus was wrong is brought up. These examples, however, never work to establish the anti-consensus position.

There are several reasons these examples fail. The first is that they are cherry picked, and not representative. Consensus in science is all about probability. The real question is – does the degree of scientific consensus predict the probability of being overturned? Of course it does. In fact, I challenge anyone to find an example in modern times of a solid (>99%) scientific consensus being overturned. You have to go back to the early days of any particular science, when the “consensus” was really just an assumption or guess at the time, not built on mature scientific research. Once a strong consensus is established by evidence, it tends to be sticky.

The other reason the examples fail is that they are almost always problematic, meaning they are simply wrong in some critical detail. The role of H. pylori in gastric ulcers, in fact, garnered early interest and rose steadily as more and more evidence emerged, for example. Often the examples are too far back in time to be relevant. Or the change really represents the evolution of scientific theory as new evidence and models come into play. But learning new stuff is not the same as overturning existing knowledge. Newton’s mechanics still mostly work, even though we now know they are a special case of relativity. DNA is still, and will forever be, the molecule of inheritance, despite recent advances in epigenetics. The standard model of particle physics may be incomplete, but it’s not going anywhere, and neither is the periodic table.

So when it comes to AGW the question is – how solid is the scientific consensus and how confident are its conclusions? There are many studies addressing this question, which I review here. The median figure is around 97%, but there are those who argue that it is really >99%. The obvious question is – does it matter? I think it matters a little. Consensus is a continuum, and the stronger it is the lower the probability that it will be overturned. But even at 97%, that is certainly enough of a consensus on which to base public policy.

But again – when it comes to scicomm, none of this seems to matter. The research shows that on this issue (and these things do change issue to issue) the only factor with a significant effect on acceptance of AGW is political affiliation. Education level, scientific knowledge, and other demographics have an insignificant effect. What appears to be going on here is that anti-AGW propaganda has successfully turned the issue into a culture war, leavened with conspiracy thinking. If you approach the issue politically, ideologically, and culturally, than logic and evidence does not matter. It is also easy to dismiss any argument or evidence from the other side as the result of ideology.

After hundreds of exchanges with AGW deniers, this pattern is overwhelming. Anti-AGW arguments are mostly grounded in politics – rejecting the liberal conspiracy to take over the economy using AGW hysteria as justification. Education level and scientific literacy only affect the sophistication of the arguments used to backfill this position, but they aren’t enough to change the position.

At this point I would love to be able to say – and here is the solution. But again, nothing has worked so we don’t know what the solution is. That doesn’t mean I give up. My sense is, and this is supported by some research, that we need to teach critical thinking skills. This may work on an individual level, but we don’t have the infrastructure to execute this anytime soon on a societal level. There the only hope is a change in the politics and culture itself. That requires leadership, and given recent events I am not holding my breath. My prediction is that a thin political majority will emerge sufficient to take action only after there have already been serious and obvious consequences. This will still not move the hard core denier, but it may adequately marginalize them.