Activists, media, and politicians infected with dangerous overconfidence on climate change

"The fool doth think he is wise, but the wise man knows himself to be a fool." So said the character Touchstone, the court jester, in Shakespeare's comedic play As You Like It.

If England's greatest poet and dramatist were still alive, he would point out the strange situation we find ourselves in today, namely that the people who know the least about many topics are often the most vocal in supporting their causes. For example, in the climate change debate, activists claim with self-righteous certainty that we are causing a climate emergency due to our emissions of carbon dioxide, and that vast changes in our society are needed to avert catastrophe. Yet experts aren't nearly as confident. Although the media and world leaders tell us that the science is settled, a deeper dive into the issue reveals that it isn't as clear cut as they make it out to be.

This is an example of the Dunning-Kruger effect. The Dunning-Kruger effect is a cognitive bias that makes us more likely to overestimate our abilities when our skills or knowledge aren't adequate and to underestimate our abilities when we have greater developed skills or knowledge. A cognitive bias is an error in our thinking that affects how we perceive others, ourselves, or the world and influences how we make decisions. This can lead to irrational judgements and beliefs of certainty despite lack of credible evidence. In addition to the Dunning-Kruger effect, some other cognitive biases are the confirmation bias (interpreting new information as confirmation of your pre-existing beliefs), self-serving bias (the tendency to take personal responsibility for positive outcomes and blame external factors for negative outcomes), and availability bias (thinking that things that readily come to mind are more common than is actually the case).

In the seminal paper by Kruger and Dunning (1999), "Unskilled and unaware of it: How difficulties in recognizing one's own incompetence lead to inflated self-assessments," they found that we often overestimate our abilities despite lack of knowledge in a certain subject. Although the applicability of the Dunning-Kruger effect is debated, it can explain many situations where people are overconfident in their assessments despite lack of knowledge, as well as the more modest outlook of subject matter experts. A striking example of the latter can be seen with Socrates' famous statement in Plato's Apology, "I neither know nor think I know." Socrates was seen as one of the wisest men, and this humility is often characteristic of philosophers and scientists who, while being truly knowledgeable, recognize the limitations of their knowledge when there is much more that can be known.

In Dunning and Kruger's study, they had people perform a test and then guess their score as a percentile relative to others. Participants were separated into quartiles based on their estimated scores: those who performed in the bottom 25%, those who scored in the top 25%, and those who scored in the two middle quartiles. For each quartile, the average performance score and the average estimated score was plotted, an example of which can be seen in the graph below.

Source: https://bruceabernethy.com/assets/mirror/1999-kruger.pdf

We can see a significant overestimate of 46 percentile points for participants in the lowest quartile, illustrating that the effect is most significant for those without as much knowledge. Participants in the top quartile, while underestimating their result, only did so by less than 20 percentile points.

In the climate change debate, we see this played out point by point. Activists are the loudest and most dramatic in their demands and confidence that we are entering a human-caused climate crisis. Scientists, on the other hand, are much more wary of making such zealous claims, even those who support the scare in general.

At COP30 in Belem, Brazil last month, dozens of indigenous protestors with batons forced their way into the conference to call for more action on climate change and protest the environmental damage caused by developments. They caused injuries to security guards, and throughout the week, others joined the protestors outside the conference to demand for further action. This clearly illustrates the confidence these protestors had in their mission and "crusade" to stop climate change, despite the fact that it is extremely unlikely that any of them are climate scientists or have in-depth knowledge of the field.