Anticipation is mounting as one of the world's most important public figures prepares to convey a key message on ecology and the environment that could have a profound impact on the way 1.2 billion Catholics think about their relationship with the planet. Some believe it could even be a game-changer in the global struggle to deal with climate change.

Pope Francis' upcoming encyclical on ecology, due to be published Thursday, June 18, is expected to portray climate change as fundamentally connected to human rights and the plight of the world's poorest citizens, and to stress an urgent need for action.

"It means making change that leads to simpler, fuller lives, when we don't just consume resources like crazy," Lonnie Ellis, associate director of the Catholic Climate Covenant told DW.

"But it also means advocating and trying to change systems and laws. Francis has been pretty clear that we need to move away from a throwaway culture and an economy of exclusion."

Francis has been hailed as a superstar pope. The first non-European to be installed in the Vatican in more than a millennium, he has been outspoken on poverty and human rights, championing the marginalized and entertaining the faithful with a series of headline-grabbing one-liners. And he hasn't shied away from forceful criticism of powerful ideologies of the day, from free market economics to consumer culture.

Speaking at a Caritas event in New York last month, Francis warned that the powerful would face God's judgment if they failed to preserve the earth so that it can support all the world's people. He has previously called exploitation of the environment a sin.

Now the encyclical - described as a policy paper for the Catholic faith - intends to put environmental protection at the heart of religious practice.

Solar-powered churches

A papal encyclical - among the most important forms of Vatican communication - addresses a key aspect of Catholic doctrine

Eco-conscious Catholics say it is already having an impact - even before publication.

"We are getting so many more requests to come to schools and parishes and give talks about care for creation - there is so much buzz about this," said Ellis, who believes the faithful are ready to address the issue on a spiritual level.

"All this talk about the science - all the charts and graphs out there - I think people are hungering for a different kind of conversation about the moral issues at stake here."

Jeffry Odell Korgen, a lay Catholic ecclesial minister who works with the interfaith environmental group GreenFaith, pointed to signs in the US that environmental action is becoming a matter of faith.

"More and more churches are installing solar panels on their roofs," Korgen told DW. "Improving energy efficiency now says something about moral practice and putting faith into action."

Teresa Berger, a professor of theology at Yale School of Divinity, is planning to begin generating her own green power, too.

"I think the encyclical will have different impacts in different contexts - for me it will mean putting solar panels on my house - finally," she told DW. "With the papal encyclical coming out I said: The time is now."

Berger says that while stewardship of god's creation and care for the poor have always been at the heart of Catholic teaching, she expects Francis to convey a clear and compelling ecological message. She would like to see his followers in the US respond by, for example, abandoning their cars to get to Sunday Mass.

Less than half of Americans view climate change as a major threat, and activists there hope the pontiff's message will convince people of the urgency of the problem. In other parts of the world, the document will be seen as an important affirmation of problems the public is only too aware of.

Courage to take a stand

"In many parts of Argentina and Latin America, there is a lot of concern over actions that are having a huge environmental impact," said Pablo Canziani, a climate scientist working with Accion Catolica Argentina, pointing to large-scale mining projects and monoculture cultivation of genetically modified crops as major issues.

Francis is also hugely popular in his native Argentina, which globally has among the highest rates of public concern over climate change

"These kind of activities are being done without any purpose of fostering development, but purely in the service of greed. The only way to change this is through strong moral leadership," Canziani said.

Aside from taking a stand against one of the seven deadly sins, this could spur people to put greater pressure on politicians regarding environmental issues and human rights - and help give legitimacy to protestors defending both.

"Sometimes people are afraid of taking a stand on something that affects them. This encyclical will give them courage," he told DW.

In the Philippines as well, humankind's impact on the planet is no longer an abstract concept, with a link drawn between climate change and typhoons that have devastated the country in recent years.

As Typhoon Hagupit approached the Philippines in December, the Archbishop of Manila called on churches to pray for safety - and for forgiveness for sins against creation.

But Lou Arsenio of Archdiocese of Manila Ecology Ministry says more must be done to educate people about "the connection between ecology and spirituality."

"We have had difficulty getting people to see ecology as major concern, despite the fact we are having many problems because of climate change," she told DW. "We are hoping that the encyclical will open the eyes of many of our priests as well as lay people."

Ruffling feathers on the right

But not everyone in the Catholic Church is looking forward to the document. Some conservative commentators have accused the pope of jumping on the "bandwagon" of the global environmental movement, or of straying from his area of expertise.

Earlier this month, US presidential candidate Rick Santorum, a Catholic Republican who has argued against gay rights, contraception and abortion, said the church should leave science to the scientists and focus on theology and morality.

Francis has a history of ruffling feathers on the political right. His first apostolic exhortation in 2013 criticized global capitalism and free market economics, challenging the "trickle down" theory that society as a whole benefits from economic growth.

Pope Francis choose his papal name based on Saint Francis of Assisi, the patron saint of ecology

Advocates of the pope's stance on the environment point out that Jesus Christ himself upset the status quo. Some say controversy should be welcomed.

"That's what so exciting," Korgen told DW, stressing that the pope has framed environmental protection as very much a moral issue.

"Wherever we stand on the political spectrum, it is important to look in particular for these parts that challenge us, and engage with that challenge."

Inspiring others

The document will be released in various languages, and United Nations Secretary General Ban Ki-moon along with climate change campaigners around the word have already welcomed it as an important signal ahead of UN climate talks in Paris later this year.

And a time when ever more people are directly affected by the impacts of climate change - and pressure mounts on religious institutions to take the lead on issues such as divesting from fossil fuels - Korgen is convinced the encyclical will send ripples beyond the global Catholic community.

"I think it will spur action," Korgen said.