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Survey data shows that most people believe climate change is happening, but many don't act, and as a postdoctoral fellow in Annenberg School for Communication Professor Emily Falk's Communication Neuroscience Lab, Alyssa (Allie) Sinclair has thought a lot about why that might be.

"People may struggle to understand how the issue is relevant to them or people they know [relevance], focus on the present instead of future consequences [future thinking], or feel like their actions don't matter [response efficacy]," says Sinclair, also a member of Professor Michael Mann's Penn Center for Science, Sustainability, and the Media, a joint venture of the Annenberg Public Policy Center and School of Arts & Sciences.

Building off health behavior studies and other literature in psychology, neuroscience, and communication, Sinclair led an interdisciplinary team of researchers examining how to overcome these barriers to climate action. In an "intervention tournament" with 7,624 U.S. adults, Penn researchers including Sinclair, Falk, and Mann tested 17 interventions targeting the themes of relevance, future thinking, and response efficacy to see which were most effective for motivating action.

"We find that helping them think about the future—especially when that future involves themselves and people they care about—is the most effective way to motivate action," Sinclair says.

This is true for motivating both individual actions, such as driving less or eating vegetarian meals, and collective actions, such as donating or volunteering. Interventions emphasizing relevance—why climate change should matter to you and people you care about—were the most effective in motivating people to share articles and petitions.

The team's findings are in the Proceedings of the National Academy of Sciences.

"There's been a growing number of efforts from other teams and from us to systematically look at what works and what doesn't work, and it's been really gratifying to see the fruits of that—to see that people are open to change when we give them the tools and resources," Falk says. This study builds on her research on messaging to motivate positive changes in health behaviors.

This study embodies the call in Penn's strategic framework, In Principle and Practice, for an "all-in" university effort to do more in the challenge of climate.

"This work reflects the emerging collaborations across campus in the climate space, something that I'm trying to foster in my new role as Vice Provost for Climate Science, Policy & Action," Mann says, adding that "understanding how to communicate the science and its implications in a way that leads to useful policy and action is central" to the role.

The work is also inventive in its approach. Sinclair, the paper's first author, explains that the traditional model of testing whether one idea works makes it difficult to compare findings across studies, so the researchers decided to test many ideas. She says intervention tournaments are not new, but they are rare, as they are ambitious efforts involving a lot of time, energy, and expertise.

Findings

The study—conducted among participants who affirm the existence and anthropogenic causes of climate change—found that two strategies targeting future thinking had the strongest impact on intentions to act: imagining oneself experiencing a negative future that could result from not addressing climate change and writing a letter for a child to read in the future. Both increased intentions to engage in both collective and individual actions.

The letter-writing approach also had the highest impact on intention to share petitions, both broadly on social media and directly with another person. Two interventions targeting relevance had the greatest impact on intention to share news articles: describing why news headlines on climate change matter to them and to people they know. They found that interventions emphasizing response efficacy increased the perceived impact of pro-environmental actions but did not consistently inspire action.

Some strategies exist at the intersection of relevance, future thinking, and response efficacy: brainstorming short-term personal benefits from engaging in pro-environmental behaviors in the next six months and developing a detailed plan to achieve an individual or collective goal. These also increased intentions to act.

Researchers also identified ineffective strategies, showing that receiving information about reducing one's carbon footprint did not increase intentions to act. This is important because many environmental agencies promote actions focused on individual carbon footprints, but these strategies may not be effective.

"There is a huge gulf between the actions people tend to think make a difference, and the actions that actually make a difference when it comes to climate action," Mann says. "Practitioners, i.e. communicators and organizations that participate in climate communication, could increase their effectiveness by incorporating the key findings of this and related work."

Sinclair says the perspective of climate scientists has been missing from a lot of behavioral science work on climate change, and Mann advised the team on what actions matter most.

The road ahead

The authors note that while research shows "behavioral intentions are reliably related to actual behavior," an important goal for future work is to test whether their top-performing interventions change real-world behavior. Such studies could measure the impact of a particular action—such as donating to environmental organizations or signing up for renewable energy programs—or take a longitudinal approach by repeatedly assessing participants' behaviors in real time.

In the future, the team aims to adapt their findings into interactive online tools, work with museums to highlight the leading interventions through displays and interactive activities, and partner with environmental journalists.

"Overall, we recommend illustrating future scenarios and emphasizing the personal and social impact of climate change as leading strategies to promote behavior change and information sharing," they write.

Additionally, they note that their findings around behavior change, motivation, and information sharing have potential applications in domains beyond climate action, such as for motivating healthy behaviors or civic engagement.