CHICAGO, June 17 (Reuters) - Some U.S. scientists are expressing hope that Pope Francis' encyclical on global warming embracing the view that it is mostly caused by human activities will change public opinion in the United States, where the issue is highly politicized.
Texas Tech University climate scientist Katharine Hayhoe said the pope's document is important because more facts alone will not convince climate change skeptics.
"We have to connect these issues with our values," said Hayhoe, who described herself as an evangelical Christian.
Hayhoe said the pope's document will expose the "cognitive dissonance" in using religious arguments against global warming - for example, that God would not let this happen.
"The real reason you object to it has to come out of the closet," Hayhoe said.
The pope is due to release the document on Thursday. A leaked draft shows that Francis calls for urgent action on climate change and repeats the scientific consensus that the world is warming mostly thanks to human activity. That position has been contested by conservatives, particularly in the United States.
"What I think it will be effective at is reframing the basic essence of climate change as a moral issue - indeed, a moral imperative," said Michael MacCracken, chief scientist for climate change programs at the Climate Institute in Washington.
Michael Greenstone, an economics professor who directs the University of Chicago's Energy Policy Institute, said it is becoming "increasingly uncomfortable and complicated" to deny climate change, and the pope's statement will make it even harder.
"I think the dam will break at some point," Greenstone said. "The arc of history bends towards truth."
A Pew Research Center poll released on Tuesday found that 45 percent of Americans and 47 percent of U.S. Catholics attribute global warming to human causes.
DePaul University environmental science professor Mark Potosnak said he hopes the pope's stance will change opinions.
"It's really a moment to reframe the debate and move away from the partisanship, and emphasize to Catholics and others that it should really be a unity issue," Potosnak said. "There's been a lot of bad information out there. It's nice the pope had a voice here, and I think a lot of people are ready to listen."
Catholic priest Thomas Reese, who writes for the National Catholic Reporter, said the encyclical will raise the climate conversation to another level.
"Suddenly, you're not just doing it for the polar bears, you're doing it for God," Reese said. "I think it makes a big difference."
(Reporting by Mary Wisniewski; Editing by Will Dunham)