Alarmed by accumulating scientific evidence that global warming could imperil the planet as we know it, environmentalists have been pressing for strong government action to deal with “climate change.” Yet for the American public, this issue is not a central worry and concern can be volatile. During 2006 and early 2007 public worry about threats from climate change grew. Environmentalists hoped that the arrival of a new president might open the door for strong regulatory and legislative action. But public concern started to wane by late 2007, and then plummeted sharply in 2008, just as comprehensive legislation was debated.
What happened? Given the ubiquity of public opinion surveys, this question would seem easy to answer. But questions about the threat of climate change are relatively recent. And speculations about why public attitudes might change range widely and focus mostly on personal experiences and mass social psychology. It has been hard to weigh factors that might matter, because views on this issue are measured only episodically by one polling organization at a time.
Using a well-established method in opinion research to combine results from all available surveys, we have created a “Climate Change Threat Index” that measures the level of public concern every three months from 2002 through 2011. Statistical models allow us to assess the causal impact of shifts over the same period in many factors that might have influenced public thinking. Our results show that partisan battles have had a major impact on public opinion.
The Drivers of Fluctuating Public Concern
To lay out our results, we begin with the factors that did not prove important and move to those that had a moderate and major impact:
- Unusual Weather is Not a Factor. One popular idea is that extreme weather events that have an impact on personal experience lead to increased concern over the threat of climate change. But we found no impact on public concern from the occurrence of droughts, hurricanes, extreme heat waves, or floods.
- Scientific Information Rarely Matters. Another explanation points to understanding of scientific information. Routine scientific analyses are not read by the public and have no impact on the levels of climate concern, but we found a slight effect from the release of major scientific reports and articles on climate change in popular scientific magazines such as Scientific American or National Geographic.
- Media Coverage Has a Significant Influence: Public opinion is thought by some to reflect the extent and prominence of media coverage, and we found that changing frequencies of stories highlighting climate change did have a significant effect on levels of public concern.
- Information Advocacy Matters only if There is a Big Splash. In any political controversy, advocacy groups spend time and money trying to mold beliefs and increase the salience of their perspective. Our analysis shows that most of these efforts have little impact on public opinion, but a notable exception was the documentary movie, An Inconvenient Truth, released with much publicity in May 2006. The visibility of this movie and the Academy Award and Nobel Prize bestowed on its author, Vice President Al Gore, strongly, though briefly, boosted public concern over the following year.
- War and Economic Recession Have an Impact: Overriding events influence public opinion across the board. Both the war efforts in Iraq and Afghanistan and the economic collapse in the fall of 2008 contributed to declines in public concern about climate change.
- Partisan Opinion Leaders Exert a Large Influence: Social scientists have shown that citizens use coverage of public controversies to gauge the positions of elites they find credible, and then interpret the news based on ideology and party identifications. This has been the case with climate change. The effect of partisan statements was found to be the largest single factor in explaining the ups and downs of public worries about the threat of climate change. After the Al Gore movie made its splash, Republicans started a drum-beat of agitation in 2007 questioning the seriousness of climate change, and public concern declined. Concern briefly climbed again at height of the 2009 push for regulatory legislation by the Democratic House of Representatives – only to plummet when the GOP and conservatives made an all-out push against Senate climate-change legislation starting in the second half of 2009.
Political Action and Public Persuasion
Public opinion does not dictate what Congress or regulators do about a complex problem, even if elected politicians often point to opinion trends to justify action or inaction. Yet as our results show, partisan political conflict itself affects what ordinary Americans say about the threat of climate change. This finding raises profound questions about any approach to environmental mobilization that relies on disseminating non-political “information” to the general public.
As elites with megaphones, Republicans and Democrats are taking increasingly polarized positions – in turn influencing what the public thinks. Of course, partisan divisions over environmental issues have been widening for some time. But there is reason to think that partisan warfare has reached a new high point, stoking divisions in the public at large that may not go away soon. Given the vested economic interests at work, a communication strategy focused only on education is unlikely to raise public concern and create sustained support for action. Under the present circumstances, communications must be linked to a broader political strategy. Political conflicts are ultimately resolved through mobilization and activism. For climate change and what to do about it, the battle has been joined.
Read more in Robert J. Brulle, Jason Carmichael, and J. Craig Jenkins, “Shifting Public Opinion on Climate Change: An Empirical Assessment of Factors Influencing Concern over Climate Change in the U.S., 2002-2010.” Climatic Change, February 2012.