Trump’s campaign slogan, “Make America Great Again,” is only one prominent example of a long-standing conservative tradition of eulogizing the past. Progressive politicians often campaign with the promise of a better future. But conservatives recognize that pledging to restore a golden past resonates with their electorate. Environmentalists may want to consider using that to their advantage: a new study shows that focusing on the past is effective in getting conservatives (who are much more likely than liberals to deny climate change) to act to protect the planet.

Specifically, the key is using pro-environment messaging that focuses on preserving a greener past, rather than averting future climate disasters, according to the study, published Dec. 12 in Proceedings of the National Academy of Sciences.

Study participants were asked self identify as liberal or conservative, and were then given statements or photographs about climate change, focusing on the past and the future. Next, they were asked about their desire to act and their attitudes and feelings about climate change.

The researchers played around with a bunch of variables. In one experiment, participants read one of two messages about climate change: “Looking forward to our nation’s future…there is increasing traffic on the road” or “Looking back to our nation’s past…there was less traffic on the road.” Here, conservatives looked less favourably on the future-focused message while reading the past-focused language increased their support for environmental conservation.

In another experiment, participants were asked to allocate money between two charities—one past-focused and the other future-focused. conservatives said they would donate about $0.15 to future-focused charities vs. $0.30 for past-focused charities.

The temporal framing did not affect liberals’ pro-environmental beliefs, and they were as likely to react positively to past-focused statements on climate change as those framed with a forward looking message. However, in the charity experiment, liberals tended to allocate more money to the future than the past.

Analyzing the results of the various experiments, the study found that while liberals expressed more pro-environment views in general, when climate change rhetoric focused on the past the difference in how conservatives and liberals responded to calls to act on climate change was reduced by 77%.

“One way to make America great again would be to return the land to the way it once was—so perhaps the slogan, and the goals of climate activists, can actually come together to form common ground,” says Matthew Baldwin, a researcher at the University of Cologne, and the lead author of the study.

While climate change advocates often frame their message as a warning about the future of the planet, it might be more effective to speak about restoring the environment to its former glory. “Activists can use this research to more effectively market climate change science. We know that scientific evidence alone is often not an effective way to convince people,” says Baldwin. “Taking care to understand the audience and tailor the message to fit the audience is as important in science as it is in any other marketing domain.”