Pope Francis has drawn the world's attention with a new encyclical that urges action on climate change. But will it have an impact?
The papal letter, titled "Laudato si," or "On Care for Our Common Home," paints a bleak picture of Earth as sick and poisoned at almost every level.
"The earth, our home, is beginning to look more and more like an immense pile of filth," Pope Francis wrote in the document, which is typically sent to bishops of all Roman Catholic churches. [6 Unexpected Effects of Climate Change]
In addition, the encyclical argues that climate change is a dire threat that humans have a moral responsibility to address, and stresses that action must come soon or else problems will get much, much worse.
"A very solid scientific consensus indicates that we are presently witnessing a disturbing warming of the climatic system. In recent decades, this warming has been accompanied by a constant rise in the sea level and, it would appear, by an increase of extreme weather events, even if a scientifically determinable cause cannot be assigned to each particular phenomenon. Humanity is called to recognize the need for changes of lifestyle, production and consumption, in order to combat this warming or at least the human causes which produce or aggravate it," Pope Francis wrote.
But though the 192-page letter is clear on the urgency of climate change, whether it will change hearts, minds or policy remains to be seen.
Catholics typically don't change voting patterns because of encyclicals, said Mark Gray, a political scientist with the Center for Applied Research in the Apostolate at Georgetown University in Washington, D.C., which conducts social science research for the Catholic Church.
Still, the pope has a global influence, and the new encyclical isn't aimed at just Catholics, so there's a good chance the letter could change minds globally, said Mark Shea, a Catholic blogger for the National Catholic Register.
The Catholic Church and voting
The Catholic Church doesn't endorse specific political parties or candidates, Shea said. So, even though the encyclical calls for action on climate change, "this isn't going to be giving you voting instructions," Shea told Live Science.
For instance, the Catholic Church considers torture, abortion and birth control gravely and intrinsically immoral, and it is never considered morally acceptable to do evil in order to do good, Shea said. But Catholics also say it's permissible to remotely cooperate with evil — for example, to buy a shirt that potentially involved child labor. This means, according to the Catholic Church, a person can, in good conscience, vote for a candidate who doesn't want to address human-caused climate change, as long as a candidate supports other good policies and he or she isn't voting for that candidate because of his climate-change-denial stance, Shea said.
And even if the church generally supports action on climate change, Catholics are free to disagree on specific policies that aim to reduce carbon emissions and thereby slow down global warming, such as taxes on carbon emissions, carbon cap-and-trade-programs, or increased funding for electric vehicles or sustainable wind and solar power.
As such, there is a lot of room for individuals to consult their own conscience and decide whether the climate change issue should alter their voting patterns or political focus, Shea said.
Historically, encyclicals have not made much of a dent in voting patterns, Gray said. There is one exception: Social scientists think a 1963 encyclical by Pope John XXIII, along with other statements from the church against nuclear armament, may have shifted attitudes in the 1980s. Still, even that didn't lead people to change their party affiliation, he added.
"The party tends to trump religion in the United States in terms of Catholics," Gray said.
Hard-liners on either side of the political spectrum are likely to cherry-pick the new papal letter to support their own viewpoints, Shea said.
For instance, the encyclical not only urges climate change action, which conservatives are typically skeptical of, but also criticizes more liberal approaches to reducing poverty, such as establishing reproductive rights and reducing the birthrate.
"My suspicion is that both lefties and righties will cannibalize the encyclical for the bits that they like and then use them to attack each other," Shea said.
Beyond that, Catholic voters are rarely single-issue voters, Gray said. They may choose party affiliation because of several issues, and just live with discomfort when their party's platform is at odds with Catholic teaching, Gray said. [Infographic: The World's Catholic Population]
Still, the new encyclical may shift attitudes among some Catholic independents, Gray added.
The encyclical could change the conversation in other ways, Gray said. The letter may put some Catholic Republican politicians in the hot seat over their unwillingness to tackle climate change, Gray said. And it may spur more voters to call congresspeople and grill them on their climate change stance, he said.
The new document may also make a big splash in the rest of the world, Shea said. Pope Francis' encyclical is addressing "every person living on this planet," not just Catholics
"This is a letter to the world, because he understands it as a global problem," Shea said.
Given Pope Francis' global popularity, it may be the first time that non-Christians and non-Catholics hear the Church's integrated approach to both the natural world and human nature, and that could provide an opportunity to change minds, Shea said.