Expert Commentary

After an experimental online advertising campaign, Republicans shifted their views on climate change

Republicans exposed to a monthlong online video campaign delivering facts on climate science from trusted messengers, such as evangelicals and retired military, showed higher rates of belief that global warming is real and caused by human activity.

global warming
Excessive heat and nearby wildfires obscure the San Francisco skyline over the Labor Day 2020 weekend. (Patrick Perkins / Unsplash)

Republicans resistant to accepting that global warming is real and caused by humans could be swayed by online videos featuring climate science facts delivered by trusted messengers, such as evangelicals and retired military personnel, suggests recent research in Nature Climate Change.

The researchers conducted a monthlong experiment delivering the online videos to Republicans, Democrats and independents in two competitive congressional districts. Republicans in particular showed large upticks in their understanding that global warming is real and could impact future generations. The videos were designed to reach skeptical Republicans, though some Democrats were also convinced by the videos.

Addressing climate change is a top concern for 10% of Republicans and Republican-leaning Americans, compared with 49% of Democrats or those who lean Democrat, according to a Pew Research survey of 13,749 U.S. adults taken in late April.

“Because ambitious and durable climate policies require bipartisan support, it is important to engage more Republicans,” write Matthew Goldberg, Abel Gustafson, Seth Rosenthal and Anthony Leiserowitz in the recent paper, “Shifting Republican Views on Climate Change through Targeted Advertising.”

They add: “Although shifting basic beliefs and attitudes about climate change does not always lead to changes in behaviors or policy support, educating people about basic climate realities is an important foundation for problem recognition and solution seeking.”

The power of trusted messengers

Controlled lab tests have indicated right-leaning Americans can be swayed on climate science with messaging that resonates with values typically associated with conservative politics, such as free market approaches to tackling climate change.

The current research is among the first to test such messaging in a real-world field experiment. The authors recruited 1,600 respondents in two competitive congressional districts: the 2nd Congressional District in Missouri, near St. Louis, and the 7th Congressional District in Georgia, near Atlanta.

“Groups that are mixed tend to be more persuadable because they’re more likely to be challenged on their views, or exposed to information not directly in line with what they already think,” says Goldberg, an associate research scientist with the Yale Program on Climate Change Communication.

Respondents were variously recruited by automated voice messages sent to their landlines, text messages to their cell phones and an online survey panel. The researchers’ goal was to reduce unknown biases that could arise from using a single recruitment method.

The researchers delivered videos from the New Climate Voices campaign to select respondents through Facebook, YouTube and banner advertisements across the web from July 19-August 20, 2019. The videos, which the researchers helped develop for this study, feature four messengers delivering climate information targeted to convince Republicans that the earth is warming and that warming is caused by humans:

The videos reflect each messenger’s personal perspective and background. Keys, for example, talks about how climate change is a threat to national security.

“Why does the military care about climate change?” he says in one video. “The answer is, we see it as a threat to our country. We have at least 19 bases around the world affected by rising sea levels.”

After the campaign, the researchers found 40% of Republicans exposed to the videos said global warming is real compared with 33% of Republicans who didn’t see the videos. Likewise, 29% of Republicans who saw the videos think global warming is caused by humans, compared with 19% of those not exposed to the videos. And 41% of Republicans who saw the videos think global warming will harm future generations, compared with 25% of those who did not see the videos.

“The big, overarching question — or the potential sense of uncertainty — is the translation from the lab into the field,” Goldberg says. “When people see these advertisements on their Facebook feeds it’s nested in everything else they see, which could easily contradict it. So the fact that this could be effective in that environment is really encouraging.”

The researchers’ hypothesis that trusted messengers can sway opinion on climate change stems from something called social identity theory. The idea is that people align with particular social and cultural groups based on shared beliefs — it’s about where individuals see their place in society. Drawing on personal experience and upbringing, an individual might think of themselves as some combination of urban, rural, conservative, liberal, evangelical or atheist, as just a few examples.

Credible messengers have a better shot at changing minds — and credibility often stems from expertise.

For example, someone who identifies as a strong supporter of the armed forces would likely be more open to a climate science message from an Air Force general with decades of military experience rather than from a newly enlisted airman, or someone who has never served.

Research methods — plus, how Democrats reacted

To conduct their study, the authors randomly assigned zip codes within the two congressional districts as either control or treatment zip codes. The New Climate Voices videos were delivered to the treatment zip codes, but not to the control zip codes. The researchers built treatment and control groups that were broadly similar in terms of age, sex and political leanings.

The researchers surveyed an initial 1,600 respondents from the treatment and control zip codes about their beliefs on global warming — before the advertisements were delivered. They conducted this pre-campaign survey to rule out factors other than the advertisements that might affect beliefs about climate change, such as whether there was already a general rising understanding that the accelerated pace of global warming has been driven by human activity since the Industrial Revolution.

After the month of advertisements, the researchers administered the same survey on global warming to a different group of 1,600 respondents: 800 received the ads, 800 did not. In total, there were 540 Republicans, 418 Democrats, 502 independents and 140 respondents who did not affiliate with a political ideology. The treatment group received an average of roughly seven videos during the campaign.

While the campaign was designed to inform Republicans — and Democrats started out with higher levels of belief in global warming — the researchers did observe increases of several percentage points among Democrats in two areas. Some 93% of Democrats who saw the videos said global warming is real, compared with 87% of those who did not see the videos. And while 85% of Democrats exposed to the videos think global warming is caused by humans, that figure was 76% among Democrats not exposed to the campaign.

Still, the overall results were driven by swayed Republicans, according to the paper. The research doesn’t capture how long the effects lasted or how the advertisements would play in heavily Republican congressional districts.

But, it provides evidence that credible messengers in real-world advertising can move the needle when it comes to belief in and concern about global warming, Goldberg says. The results indicate that climate change “isn’t something only extremely liberal folks care about,” he adds.

Additional reading

Messaging for Environmental Action: The Role of Moral Framing and Message Source
Kristin Hurt and Marc Stern. Journal of Environmental Psychology, April 2020.

Promoting Persuasion with Ideologically Tailored Science Messages: A Novel Approach to Research on Emphasis Framing
Kate Luong, R. Kelly Garrett and Michael Slater. Science Communication, July 2019.

What Predicts Selective Exposure Online: Testing Political Attitudes, Credibility, and Social Identity
Magdalena Wojcieszak. Communication Research, May 2019.

Improving Climate Change Acceptance among U.S. Conservatives through Value-Based Message Targeting
Graham Dixon, Jay Hmielowski and Yanni Ma. Science Communication, June 2017.

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