A ‘carbon clock’ in front of the Reichstag in Berlin shows the time remaining before global average temperatures will rise by 1.5 °C if carbon emissions continue to rise at the current rate.Credit: Sean Gallup/Getty

A study in Germany suggests that people have reasonably good grasp of the science surrounding climate change, but occasionally overestimate their understanding1.

Psychologists presented 509 volunteers with 8 scientific statements about the causes and consequences of climate change, and asked them whether the claims were true or false. Participants were then asked to indicate how certain they were that their answer was correct, according to established science, on a scale ranging from guessing (50%) to certainty (100%).

Most participants correctly identified true statements — and were relatively confident that their judgements were correct. But people weren’t as good at identifying statements that were false, despite being just as confident in their answers (see ‘Inconventient truths’).

For example, more than three-quarters of people successfully identified true statements that said that snow in the Northern Hemisphere had decreased in recent decades, and that human activities were the main cause of the rise in greenhouse gases. Their levels of self-reported confidence roughly correlated with these success rates, although for three of the four true statements, people slightly underestimated their knowledge.

But only 24% of people correctly identified that a statement linking rising greenhouse gases to risk of skin cancer was false. And, on average, they said their confidence in their judgement was a relatively high, at 75%.

For comparison, the study team asked 207 German climate-change researchers to verify the same set of true and false statements. On average, the scientists responded with both greater accuracy and with more confidence in their knowledge than citizens.

Confident decisions

People’s confidence in their knowledge of the facts is important when it comes to decision-making, says Helen Fischer at Stockholm University, who led the study. “People who trust in the solidity of their understanding of climate change, and that of their informants, are more likely to change their behaviour than citizens ignorant of the science or relying on mere guesswork,” she says. Researchers have extensively studied people’s attitudes towards climate change and how this relates to their education, personal values and political leanings, she adds. But the research doesn't usually focus on how confident people are in their knowledge.

The team was keen to base its study in Germany, where the policies aimed at curbing climate change — such as pricing carbon emissions from cars and buildings — has generated heated debate.

The work shows how important it is that the government’s climate policy is accompanied by a clear communication strategy, says Brigitte Knopf, secretary-general of the Mercator Research Institute on Global Commons and Climate Change in Berlin. “If, for example, it combines carbon pricing with revenue-neutral refund for households, it can avoid a burden on lower income groups in particular,” she says. “But it is important that it makes people aware of this in a catchy way.”