The vast majority of scientists – well over 90 percent by most measures – accept the evidence that humans are the driving force behind our current climate change. However, that figure is much lower among the public. One possible explanation for this discrepancy is that the public does not understand how strong the scientific consensus is. If people think that scientists are divided on this, they are more likely to find their own opinion justified, even if it goes against the conclusions of the people with the most relevant expertise.
Researchers have now looked at how people in the US react when told about the near unanimity of the scientific community on the subject. They found that results vary geographically, with a stronger response in states that are more politically conservative. This roughly compensates for the lower acceptance in the states initially, meaning all states look more or less the same.
The problem here is usually referred to as “consensus messages.” The idea is that many members of the public don’t fully realize how unified scientific opinion – the consensus – currently is. If they did, the public would be more likely to accept scientists’ conclusions and perhaps demand policies that address climate change. And there’s a lot of room for improvement here, as only about 10 percent of the American public correctly acknowledges that the scientific consensus on climate change is over 90 percent.
There is some evidence to support the idea that consensus messages can be valuable. The researchers behind the new work cite studies showing that people who don’t accept the scientific reality of climate change also don’t seem to know that scientists are almost unanimously agreed that it’s real. In addition, the awareness of scientific disagreement on environmental issues makes people less inclined to accept policy solutions. Still, no direct link has been shown between consensus messages and support for policy solutions, and it’s unclear whether knowing what scientists think changes personal opinions significantly, so the concept remains controversial.
The researchers did not attempt to address this controversy; instead, they just looked to see if consensus messages stuck. To do this, they have prepared a series of polls to address the issue. The study involved asking people about two additional issues so they wouldn’t recognize that the real topic was climate change. As part of a series of questions, people were asked to move a slider along a scale from one to a hundred to indicate what percentage of scientists believed man-made global warming was occurring.
Shortly after, they were told the actual figure (along with some other climate facts); later they got the same questions. That may sound more like a test of short-term memory, but the point is whether the mention of the existing consensus has made it through the filters people use to reject information they don’t like.
stands for state
Overall, the consensus message had an effect, increasing acceptance among respondents by 16 percentage points. But the researchers surveyed enough people (more than 6,000) to break down the results geographically. And here they got some unexpected results.
For example, you might think that consensus messages are resonating in California, a state with extensive public support for action on climate policy. But California came in last, moving just 12.2 percentage points in response to the consensus messages. By contrast, the places where opinions shifted the most were Wyoming and West Virginia, two coal-dependent states where climate change adoption is low to begin with. This was a general trend, with states where climate change adoption was low showing the biggest gains in recognizing the consensus to begin with.
Interestingly to say the least, the data simply suggests that you see bigger changes when there are more people around who need to be convinced. But there is an indication that there is more going on here. After the consensus messages, each state ended in the range of 81-87 percent acceptance that the consensus exists. This suggests that it is relatively easy to get to a saturation point, where there is anyone who can be convinced.
There are also some quirks in the details that suggest that this effect is not just a matter of politics. For example, relatively liberal states like Minnesota and Oregon saw bigger shifts than states like Nevada and Wisconsin, which tend to be more conservative.
Will it stick?
Overall, the results indicate that most people are willing to accept information about the scientific consensus. But the results are extremely limited and need a lot of follow-up. For one thing, it’s not clear whether the knowledge of the scientific consensus that these researchers saw will last. In the long run, people tend to align their views with those of their communities, and polls suggest that up to 30 percent of the U.S. doesn’t even believe the climate is warming, let alone that humanity is driving that change.
There is also the question of whether people will eventually believe the scientists. While the researchers behind the new results cite studies indicating that conservatives tend to delay authorities, this is one case where their scientific and political authorities are telling them opposite things. In other words, it’s still not clear whether consensus messages are enough to convince people that climate change is real, let alone a problem that requires a policy solution.
Still, the paper shows a valuable piece of the puzzle. Many have tended to treat the public as a monolithic thing when it comes to the public understanding of science. But the clear indication of regional differences makes it clear that there is not one message that works for everyone.
Nature Climate Change2018. DOI: 10.1038/s41558-018-0122-0 (About DOIs).