In surveys of Americans, climate change is an important environmental concern, but environmental concerns rank lower than issues such as national security and the economy. Advocates of climate change policies must confront the challenge that the public historically has viewed climate change as physically and temporally remote. A high-profile political event such as the Copenhagen climate negotiations or a weather-related catastrophe such as Hurricane Sandy catches attention and puts climate change on the political agenda. But attitudes about the causes of climate change and the appropriate level of government response are affected by one’s sense of personal risk (see Leiserowitz here, here and here). Partisanship may override the limits of individual knowledge: Democrats and independents are much more likely than Republicans to believe that there is solid evidence of global warming, by as much as a 30-point gap.
Throughout the 2000s, advocates experimented with a variety of frames to garner public support. The original frame of climate change as an environmental crisis focused on the effects on future generations and humankind. Such an appeal for transnational and intertemporal altruism is largely a moral claim. Indeed, some activists made this appeal through efforts such as the “What Would Jesus Drive?” campaign, an effort to link Christianity to environmental stewardship. In contrast, the green jobs orientation of the early 2000s, that then went on to infuse the rhetoric of the Obama administration, is a primarily material interest-based logic. In the late 2000s, advocates also sought to tie climate change to national security. Which of these various approaches is most likely to be successful?
In an article (open access) recently published in Research and Politics, we evaluated climate change frames with a survey experiment. We assigned a diverse sample of 330 participants recruited by a survey market research firm to one of four conditions: an economic self-interest appeal, a moral appeal, a mixed appeal combining self-interest and morality, and a control condition with no persuasive appeal (see the figure below for an example of the self-interest appeal). After reading a mock ad from an environmental organization, participants were then asked questions about their willingness to support advocacy efforts, including writing a letter to Congress, signing a petition and joining an organization.
Given the issue’s complexity, people may not be especially well-informed. We therefore expect that knowledge moderates the effect of persuasive messages on climate change and that more knowledgeable subjects are more likely to respond to a persuasive message. We measure knowledge about climate change with three questions:
- Every time we use coal or gas, we contribute to the greenhouse effect. How true is this? (“Probably true” and “definitely true” count as correct):
82 percent answered this correctly.
- The greenhouse effect is caused by a hole in the Earth’s atmosphere. How true is this? (“Probably not true” and “definitely not true” count as correct).
39 percent answered this correctly
- To the best of your knowledge, what was the Bush administration’s position on the Kyoto Protocol? (“Opposed it” counts as a correct answer):
22 percent answered this correctly
There was no main effect for the experimental manipulation on any of the behaviors, but the interaction between knowledge and experimental condition yielded significant effects for willingness to talk about climate change (F=3.51, p<.05) and willingness to sign a petition (F=2.43, p<.10) (see Figure 3 from the paper).
For low-knowledge participants, persuasive messages were either ineffective or demobilizing. However, for high-knowledge participants, both the economic self-interest message and the mixed message were effective in promoting helpful behaviors. Although these messages were not effective in promoting costlier behavior, such as donating money or writing a letter, an advocacy group could use an economic message to encourage knowledgeable people to participate in low-cost behaviors.
How can we explain these findings? Our expectation was that an economic self-interest frame was likely to be more persuasive given the costs of addressing climate change. In this context, high-knowledge subjects may be more familiar with those costs.
The economic self-interest appeal makes a claim that addressing climate change will bring jobs and business opportunities, potentially attenuating high-knowledge respondents’ costs concerns. Low-knowledge subjects, by contrast, are difficult to persuade with information.
In light of these findings, the next steps involve further work to identify what, if any, messages would persuade low-knowledge subjects or whether information might improve the persuasive appeal of self-interest frames. One particular frame that we did not explore was based on the consequences of climate change for Americans, a different interest-based logic that may be increasingly salient in light of Hurricane Sandy, Midwestern floods and devastating droughts across the Southwest. We have conducted some experiments in that vein and look forward to presenting those findings in our next project.