ARLINGTON, Va.—Dan Misleh, director of the Catholic Climate Covenant, found himself facing a skeptic recently after he outlined the coalition’s preparations for Pope Francis’ upcoming encyclical on global warming.

The woman didn’t doubt the science. She just wasn’t sure of the bishops.

Why wouldn’t U.S. bishops record messages on climate change to be played in all churches, just as they often do for annual Lenten fundraising drives, she asked. Why not distribute cards in the pews, urging parishioners to sign pledges to care for creation and the poor, through personal action and advocacy on global warming?

“So what you’re asking for,” Misleh deadpanned, “are miracles?”

Actually, Misleh expects Pope Francis’ message on climate change—anticipated in June or July—to resonate far beyond social justice-oriented Catholics like the ones in his audience that day at an annual symposium by the Peace and Justice Commission of the Diocese of Arlington, Va., in the suburbs of Washington, D.C.

The climate coalition Misleh leads includes mainstream voices like Catholic Charities USA, the Association of Catholic Colleges and Universities, and the church leadership itself through the U.S. Conference of Catholic Bishops, as well as progressive religious groups. The Catholic Climate Covenant already is laying the groundwork for sermon outlines and news conferences and events in the wake of the pope’s encyclical, “to keep it in the public eye for as long as we can,” Misleh said.

A papal encyclical is meant to provide spiritual guidance to the world’s 1.1 billion Roman Catholics, but among advocates of climate action hopes are high that this one will resonate far beyond the church. They are hoping the pope’s moral authority can help break the intractable global political gridlock over reducing fossil fuel emissions.

That may be a lot to ask of a message designed to find acceptance in a huge and diverse religious flock. But many have faith that this particular pope—who is timing the letter to influence this year’s crucial climate treaty talks in Paris—has the leadership skills to deliver.

“Arguably, Pope Francis is one of the most interesting moral voices on the planet,” said Shaun Casey, the special representative on religion and global affairs at the U.S. Department of State, in an interview. “People are listening to him who never paid attention to a Roman Catholic pope, because of his charisma and because of his courage.