Rubber stamps marking true and false
Credit: Le Moal
Covering Climate Now logo

Can you recognize the truthfulness of simple statements about climate change? Are you sure about that?

A recent study asked 500 nonscientists to verify whether climate change statements were true or false and how confident they were that science agreed with them. The researchers found that nonscientists were underconfident in their knowledge of true statements about climate change­ but were overconfident in their ability to recognize statements as false.

“The confidence we have in our knowledge directs our decisions,” said Helen Fischer, a postdoctoral researcher in environmental cognition at the Stockholm Resilience Centre in Sweden. “If you have correct knowledge but you are not confident in that knowledge, then the accuracy of your knowledge doesn’t help. We need to be confident that it is correct to base our decisions on it.”

“If you have incorrect knowledge, this is doubly bad if you have high, unwarranted confidence in that knowledge.”

Conversely, “if you have incorrect knowledge, this is doubly bad if you have high, unwarranted confidence in that knowledge, because then you will base decisions on wrong knowledge. We will make unfounded decisions.” These results were published in Nature Climate Change in September 2019.

Unwarranted Self-Doubt

The degree to which confidence in knowledge is matched by the accuracy of that knowledge is known as confidence accuracy. “For example,” the team wrote, “rejecting the statement that natural variation in sunbeams is the main driver of climate change shows accurate knowledge, but being uncertain about this rejection shows inaccurate confidence. Accepting the statement that greenhouse gas emissions are a main driver of climate change shows accurate knowledge, and being certain about this acceptance also shows accurate confidence.”

Confidence accuracy can be a powerful tool to assess people’s understanding in areas of knowledge that, like climate change, are rife with misinformation.

Confidence accuracy can be a powerful tool to assess people’s understanding in areas of knowledge that, like climate change, are rife with misinformation. The researchers measured the confidence accuracy with regard to climate change of nonscientists in Germany by presenting them with statements about the state, sources, and consequences of climate change. For each statement, a person was asked whether science agrees with the statement and to rate their level of confidence in their answer from guessing (50% confidence) to absolutely certain (100% confidence).

For comparison, the team asked more than 200 climate scientists the same climate change questions and a different group of nonscientists questions about physical and biological sciences. These comparisons revealed how high nonscientists’ confidence accuracy could be with regular exposure to scientifically valid information and how high their confidence should be given their confidence in a similar topic.

The researchers found no significant difference in nonscientists’ confidence accuracy with regard to the state, sources, or consequences of climate change. “The most striking result,” Fischer said, “is how bad [nonscientist] citizens are at telling what they know and what they do not know about climate change compared with how good they are at telling what they know and do not know when it comes to general science.”

“For the false statements, citizens appeared to have no insight into the fact that they did not know.”

On true statements, nonscientists’ confidence in their climate change knowledge was only about half what it could be on the basis of the accuracy of that knowledge—they knew the right answer but didn’t trust that they did. This doubt was greater than for nonscientists’ general science knowledge and for climate scientists’ knowledge.

However, nonscientists sometimes were unable to verify 60% of the false statements about climate change yet were very confident that they had done so. This trend was seen only for nonscientists on climate change.

Even when considering that someone might just know more about physics or biology than about climate change, nonscientists were “disproportionately bad” at assessing the limits of their climate knowledge, Fischer said. “For the false statements,” the team wrote, “citizens appeared to have no insight into the fact that they did not know.”

Katharine Hayhoe, a climate scientist at Texas Tech University in Lubbock, said that “while the first half of the results of this study are encouraging—that people were able to correctly identify true statements and felt confident about their ability to do so—the second half of this study—that they were not as able to identify the false statements even when they felt confident they in their answers—is discouraging but not surprising.”

The Impact of Misinformation

“There is no question that misinformation increases people’s uncertainty regarding what is and what is not true,” Hayhoe said. “When strong statements are made by perceived experts or thought leaders who we respect, we tend to assume they are true. Today, however, we are being fed false information about climate change on a near-daily basis.”

Fischer noted that this research tested only German citizens and that the results might be different in countries with different educational, political, and media landscapes. Future research aims to assess whether confidence in climate change knowledge correlates with belief in climate change, how people’s confidence differs before and after their exposure to misinformation, and how that confidence changes over a long period of time.

“There has been a large, long-lasting effort to criticize the science of climate change,” said climate researcher Richard Alley of Pennsylvania State University in University Park. “There is scholarship…showing that so-called ‘skeptical’ scientists have greater public exposure than mainstream scientists, so that the public message received by a large fraction of the population is that scientific uncertainty and scientific debate are much larger than they really are.”

“The take-home message is that increasing knowledge is not enough.”

“If people are not confident that scientists agree,” Alley said, “it might not be surprising that people are not confident of their own understanding.”

“If we appear very confident, this affects others,” Fischer said. “This is very risky. If someone has low knowledge but high confidence, then this will influence others, and then wrong climate change knowledge can have strong network effects, for example, with the media or the Internet.”

Although this study was not able to assess the degree to which misinformation about climate change led to the true/false gap in confidence accuracy, she said, it did underscore an important point: “The take-home message is that increasing knowledge is not enough,” she said. “What has been done a lot is to try and increase citizen’s knowledge about climate change. Now, the knowledge is out there. [People’s] knowledge is not so bad.”

“The next step is to increase confidence,” Fischer said, “not just in accurate statements but also such that people know what is true and what is untrue with high confidence. So that when they see a false statement they confidently know, ‘No. I know very certainly this is false.’”

—Kimberly M. S. Cartier (@AstroKimCartier), Staff Writer

This story is part of Covering Climate Now, a global collaboration of more than 250 news outlets to strengthen coverage of the climate story.


Cartier, K. M. S. (2020), Nonscientists struggle to separate climate fact from fiction, Eos, 101, Published on 14 April 2020.

Text © 2020. AGU. CC BY-NC-ND 3.0
Except where otherwise noted, images are subject to copyright. Any reuse without express permission from the copyright owner is prohibited.