Pope Francis' call last year for "swift and unified global action" to reverse climate change fell largely on deaf ears and closed minds, according to a study published Monday, and may indicate that in the United States politics holds stronger sway on this topic than religious authority.

In June 2015, Francis released the encyclical "Laudato si: On the Care of Our Common Home." A letter to the world's 1.2 billion Catholics, the encyclical  drew on scientific consensus to warn that climate change was a "global problem with grave implications," and posed one of the "principal challenges facing humanity." In addition, the pope highlighted the disproportionate risks climate change poses to the world's poor.

But Francis' call failed to rally any broad support among the American public, according to researchers at the Annenberg Public Policy Center at the University of Pennsylvania.

It "speaks to the relative power of politics and religion in shaping climate change opinions," concluded the study's authors.

"Laudato si"' "backfired" with conservative Catholics, who not only resisted the message "but defended their preexisting beliefs by devaluing the pope's credibility on climate change," said the paper's primary author, Nan Li, who conducted the study as a post-doctoral fellow last year at Penn. Li now teaches at Texas Tech University.

"He wasn't able to trigger an immediate change in people's opinion. People were very suspicious of it," Li said.

Encyclicals are considered authoritative statements of teaching by the Catholic Church, but are not viewed as infallible.

Li said she could not determine if  Francis' credibility on other matters was undermined by the hostile reception.

"I really don't know," she said. "There is just not enough evidence."

The study  was published Monday in the journal Climatic Change.

It surveyed 1,381 people in the week before the encyclical was released and an additional 1,374 two weeks after. Of those who replied, there were 711 Catholics.

Prior to the encyclical's release, 71 percent of American Catholics reported believing in climate change. That number remained constant in the weeks following.

The pope's message was widely embraced by Democrats, climate scientists, environmentalists, and social justice groups.

Right-leaning politicians and pundits, however, preemptively attacked the encyclical and cast doubts on the pope's competence.

Few Catholic priests used their pulpits to communicate the pope's message, according to the report, and many pastors remained silent on the matter. Of the 40 percent of Catholics who were aware of the encyclical, only 23 percent reported hearing about it during Mass.

"Many people would assume that the pope was a very influential figure and could leverage some of his believers to reconsider climate change," Li said.
"We didn't find that, especially among conservative Catholics."