5. Public opinion and perceptions

One barrier to creating wider acceptance of policy to mitigate climate change risks is the tendency people have to consider their own opinion to be the most common among the wider population, and to underestimate the number of people that accept the existence of human induced climate change, both among climate scientists and the wider public.  This was spectacularly confirmed by a 2013 survey of public opinion in Australia[i].

The survey divided opinions on climate change into four groups:  “Climate change is not happening”, “Don’t Know”, “It’s happening but natural”, and “It’s happening and human induced”.  The researchers asked a sample of over 5000 people to place themselves in the group that most closely matched their view.  They then asked each group to estimate how common they thought the four opinions were among the population at large.  The results of the survey are shown in the chart below.    The labels along the bottom show how many people placed themselves in each group.  The columns show the estimates by each group of how many of the wider public they thought held each opinion.  The dashed lines show the actual percentage in each group.  So for example, the left hand red bar shows on average  those whose own view was that “climate change is not happening” thought on average that their view was held by 43% of the public, whereas in fact it was held by only around 6% (283 out of 5036).  Those who accepted that climate change is human induced also thought their view was the most prevalent among the four possibilities.  However, in contrast to those who did not accept the reality of a changing climate, those who thought climate change was man-made still tended to underestimate prevalence of their own views, with 50% of the total sample (2540 out of 5036) actually holding this view, compared with the 40% estimated by those holding placing themselves in that group.


Indeed, the findings, which were reproduced by a second survey a year apart, showed that in every one of the four groups, each representing different views, on average people in that group believed that their own opinion was the most common, rather than any of the other three views, and also thought their own view was more common than any of the other three groups thought it was.  This tendency has been found across many different topics, and is referred to as a “false consensus” effect, reflecting for example our tendency to mix with people who tend to hold similar views to own.  Furthermore all groups estimated belief in human induced climate change to be less prevalent than it actually is.  These effects were particularly strong among those not accepting the occurrence of climate change, but even those who themselves thought that climate change is human induced underestimated how common this view is.

This matters particularly because assessing the changes in view over the year (from one survey to the second) showed that those with the greater tendency to overestimate the prevalence of their views were less likely to change them, implying that creating more accurate impressions of general public opinion might help shift opinion.  The authors note the specificity of their findings to Australia, and advocate testing in other countries.

While this research emphasises the importance of communicating public opinion, other new research[ii], also from Australia, emphasises the importance of communicating the scientific consensus.  Researchers looked over a range of topics, including smoking and lung cancer, HIV and Aids and climate change.  They found that people underestimate the degree of scientific consensus on each topic.  However, they were prepared to change their own views on a topic, increasing their acceptance of man-made climate change, if presented with information quantifying the actual extent of the scientific consensus.  Having numbers on the degree of consensus rather than just a general statement about how strong it was appears to have mattered.  The researchers used a figure of 97% acceptance of climate science by those in the field[iii].

Previous research carried out in the USA showed that people’s values strongly shape their perceptions of risk (a finding replicated in this survey), and that some personal values can make people resistant to descriptions of the science (see Page 2. of this section).  However the new research described here indicates that people may be more willing to respond to descriptions of the consensus among scientists than presentations of the science itself.   It would be interesting to see this work replicated, especially as the sample of the public was chosen for convenience (they stopped passing pedestrians) and so may not have been representative of the public as a whole in some respects.  It would also be interesting to see such work extended to other controversial topics in other cultural contexts.  This could include the science of evolution by natural selection, where in the USA lack of acceptance by those with a strong conflict of values appears resilient to overwhelming scientific consensus clearly communicated over decades.   However, as the authors note, their finding fits with other work from the USA showing that among Republicans acceptance of the consensus is the strongest explanatory variable for their own acceptance [iv].   Belief in the ability of individuals to do something effective about the problem was also found to contribute to acceptance of the science.

The authors of the first study attribute some of their findings to the particular character of the debate in the Australian media.  They note the tendency of the media to report the debate in a way that implies that there is more controversy than there actually is as contributing to this.  From this perspective, the tactic of questioning the scientific consensus adopted by those opposing action to mitigate climate change – many of whom have repeatedly suggesting that the consensus was actually weaker than it really is[v] – can be understood as highly effective.  It targets an area very likely to make a difference to people’s opinions.  This appears to have led some to adopt entrenched positions, and some have argued that the focus should be on persuading those who are not already strongly committed on the issue[vi].

But at least there can now, in view of these findings and those described in Page 2 of this section, be more clarity on the way forward: emphasise the scientific consensus, and the truth about public opinion, use straightforward presentation, including framing the problem sympathetically, use trusted means of communication, targeting especially those who remain undecided on the issue, involve those who have diverse backgrounds and values, and emphasise solutions.  No easy task, but at least the basis for a way forward.


[i] Your opinion on climate change might not be as common as you think, Z. Leviston et. al. Nature Climate Change, April 2013  http://www.nature.com/nclimate/journal/v3/n4/full/nclimate1743.html

[ii] The pivotal role of perceived scientific consensus in acceptance of science, Lewandowsky et. al. Nature Climate Change, April 2013  http://www.nature.com/nclimate/journal/v3/n4/full/nclimate1720.html

[iii] The source of this numbers is not stated in the paper as far as I could see but may be the widely cited study by Anderegg, Prall, Harold, and Schneider (2010) published in the PNAS

[iv] Rolfe-Redding et. al. Republicans and Climate Change, Yale Project on Climate Change Communication 2012  http://papers.ssrn.com/sol3/papers.cfm?abstract_id=2026002 The authors note the direction of causality is an issue but argue that their research suggests that knowledge of the scientific consensus causes acceptance, rather than the other way round.

[v] See references 20-23 in the Leviston et. al. paper.  The approaches used to throw doubt on the scientific consensus on global warming and other issues in the USA has also been well documented in the book Merchants of Doubt, Naomi Oreskes and Erik Conway, 2010.  http://www.merchantsofdoubt.org/  .The book contains more detail than many readers will need, but the website contains a link to an hour-long talk by Oreskes, which is a good starting point.

[vi] Weber, Psychology: Seeing is believing, Nature Climate Change April 2013.

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