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While Sandra Geiger was at a conference as a doctoral student, the keynote speaker asked the audience a question: What percentage of people do you think are skeptical of climate change? Some said 30%. Others 50%. But the actual figure revealed later in the presentation was much lower, around 5%.

"And that really stuck with me, this huge misperception," said Geiger, who is now a postdoctoral researcher at Princeton University. This phenomenon, when groups systematically misperceive the beliefs of others, is called pluralistic ignorance. One study had documented it for climate change in Australia, where people overestimated how many climate skeptics existed in the country. But whether the misperception was more widespread was unknown.

So when she was a student at the University of Vienna, Geiger decided to focus her dissertation on this topic. The results, recently in Psychological Science, found that pluralistic ignorance around climate-change beliefs occurs in multiple countries around the world. Geiger and colleagues also set out to understand if there were ways to attenuate these misperceptions and whether that can push people to become more active and vocal about climate issues.

"The idea of pluralistic ignorance, I think, is very important," said APS Fellow Stephan Lewandowsky, a psychologist at the University of Bristol who wasn't involved in the study. "It has downstream consequences," where if people think climate-change skeptics are more common, that stance has a stronger hold on society.

To understand the extent of pluralistic ignorance with climate change, Geiger and her colleagues gathered online survey responses of more than 3,500 participants from 11 different countries. The countries were systematically chosen for the study to gather a large and varied global sample, explained Geiger, where the selected countries differed in geography, how much of the population believed in climate change, their strictness in social norms, and how underrepresented they were in psychological research.

The administered survey began with two questions: One of the questions assessed the participant's own climate-change beliefs—whether they thought climate change was happening and whether it was human-caused. The survey also asked participants to indicate their beliefs of others: How many people in their country did they think believed in climate change? And to what extent did those people think it was human-caused?

In doing so, the researchers found that although most people agree that climate change is occurring and driven by human actions, people still underestimate pro-climate sentiments in their country. For instance, Brazil had one of the largest perception gaps, with a 20.8% difference between how many participants believed in human-caused climate change and their perception of what others believed. The gaps were consistent across countries, with Indonesia having the smallest gap (7.5%).

"For me, the surprising part was that these misperceptions are so widespread. They really were there in every single country we tested," Geiger said.

In the second part of the survey, the researchers implemented an intervention to combat these perception gaps: exposing the participants to representative public opinion on climate change views in their respective countries. Once participants had been given this information, Geiger and colleagues then measured whether they were more willing to live greener lifestyles, support climate policies, or express their opinions on climate change. However, the study found that this strategy was not very effective.

Future research, Geiger said, could dig into what kinds of messages can correct misconceptions and propel action. Previous studies have found that communicating the consensus among climate scientists can change the public's minds to a small extent. More work, too, will need to be done on which misconceptions are the most damaging and important to correct.

Regardless, speaking up and expressing your opinion, even if you're not an expert, could be a good start. This is because silence can create misguided perceptions, Geiger explained, making it seem like others do not care very much about climate change. These misperceptions, in turn, sustain a spiral of silence.

"It's important that people speak up and make their opinion heard on the topic," Geiger said. Only this way can the spiral be broken.