At this “strategic moment,” Schneider added, Francis’ emphasis on the poor provides a “real opportunity to create a climate movement that really puts people on the front lines first” and to “create space for environmental activists to be more courageous to call out the economic question.”

Schneider added that secular environmental activists have not placed economic issues “at the very center of their analysis.” Francis, he said, is drawing on an ancient religious belief, codified in the “earliest formulations of Catholic canon law,” that the “world is really the common inheritance of all human beings.” That notion of the common, said Schneider, is “coming back in secular activism in a big way” and will likely get a boost with Francis’ encyclical.

While Francis’ predecessors addressed environmental issues, he is the first pope to prioritize environmental issues and, significantly, will bring his diplomatic skills to bear in making his moral case to address it, said Nathan Schneider, a writer and columnist for the Catholic magazine America.

Although care for the environment has long been a central tenet not just of Catholicism but also of Judaism, Islam and other faiths, the environmental movement has long been animated largely by secular activism. Religious activists working on climate issues at the grass-roots level are delighted that Francis’ encyclical is expected to support the scientific consensus on climate change, declare a moral imperative to address an urgent crisis and focus on the disproportionate impact of climate change on the world’s poor.

For state and local activists like Rieber, Francis’ upcoming visit to the United States in September , during which he will address the United Nations and Congress, will “make this a visible issue, with the full strength of his office.” Rieber hopes that the pope’s discussion of climate change “will reach into areas that have not really been reached with climate change messaging — like Kansas.”

On Monday a leaked draft revealed the pope’s affirmation of a scientific consensus about “the presence of an alarming warming of the climatic system.” The final version will be released on Thursday.

“Given his large platform and the number of people, not just Catholics, he’s speaking to and for, we think it can be one of the most important, game-changing events in the whole discussion of climate change,” said Rabbi Moti Rieber, a coordinator at Kansas Interfaith Power and Light , part of a national movement aimed at mobilizing religious activists to combat climate change.

Pope Francis’ forthcoming encyclical on the environment and climate change is being met with enthusiasm among religious environmental activists, who say it could represent a transformational moment to spur increased faith-based activism and, they hope, break the political gridlock on addressing the climate crisis.

In American Catholicism, the encyclical is a highly anticipated reaffirmation of Catholic teaching. It is drawing attention because it marks the first time a pope has written on the environment in an encyclical — or papal letter on faith, morals or theology. It will also likely have a big impact because of Francis’ enormous popularity, said Dan Misleh, the executive director of the Catholic Climate Covenant, which works with other Catholic organizations, including the United States Conference of Catholic Bishops (USCCB), to implement a 2001 statement from the conference on climate change.

Whereas the encyclical is expected to communicate the urgency of the issue, the USCCB statement called for “a civil dialogue and prudent and constructive action to protect God’s precious gift of the earth’s atmosphere with a sense of genuine solidarity and justice for all God’s children.”

Recent polling shows that Catholics are divided on climate change, by ethnicity and party affiliation. According to data collected by the Pew Research Center, 62 percent of Catholic Democrats believe climate change is caused by human activity and “poses a serious problem,” a belief shared by only 24 percent of Catholic Republicans. Similarly, according to the Public Religion Research Institute, nearly three-quarters of Latino Catholics say climate change is a “crisis or major problem,” compared with 53 percent of white non-Hispanic Catholics.

Schneider maintained that the USCCB is not known for its concern about climate change. But, he said, “you see the sisters leading the way in all sorts of respects,” citing the Sisters of Loretto order’s efforts at fighting fracking in Kentucky and other nuns’ organic farming and environmental advocacy linked to Catholic social teaching. The nuns’ activism, he said, “hasn’t been taken seriously enough by the hierarchy” but is firmly rooted in the same theology driving the encyclical.

While papal encyclicals are rarely anticipated outside Catholicism, enthusiasm is running high for the pope’s climate change statement among a range of faith-based environmental activists. Religious environmental activists are hoping the encyclical will boost grass-roots organizing, interfaith cooperation and, ultimately, the political will to implement effective policy.

Ched Myers, a writer and organizer who works with Bartimaeus Cooperative Ministries, a Southern California social justice group that in the last decade has focused on climate change, said the encyclical would give that work “more traction.”

Even before the encyclical’s official release, said Myers, it “has already animated interfaith initiatives that I think are unprecedented.” He noted that the encyclical has inspired ecumenism on the issue in Christian communities and a rabbinic letter on the climate crisis signed by over 340 rabbis. The day of its release will coincide with the first day of Ramadan, as many Muslims press for a green Ramadan.

Because “the resistances to climate catastrophe are ideological, not scientific,” said Myers, Francis could help shatter stereotypes that religious people are climate change skeptics. The pontiff, said Myers, will “help popular culture in general overcome the notion that religious communities resist what science is saying on this point,” a prospect that excites scientists frustrated by the protracted political stalemate on climate.

Myers said faith-based environmental activism is “broader and deeper” than most people realize, particularly at the grass-roots level. “This encyclical is going to legitimate and strengthen that sector of the grass roots in a huge way,” he said.

He added that organizers “really need religious leaders to go very broad and very deep in their statements, and this pope is doing that,” particularly by “firmly anchoring this to a civilizational crisis” linked to poverty and inequality of resources.

Ultimately, though, activists are placing faith in the pope not just as an inspirer of activism but also as a broker of political and policy solutions, especially with the United Nations Conference on Climate Change to take place in Paris later this year.

Bill McKibben, a co-founder of the global climate movement 350.org, said Francis “is not just a moral arbiter. He’s also a canny observer of world politics.” With the encyclical, “he’s demonstrating that the time has come for the world to act. There’s enough consensus — or there will be once he’s done — for the world’s leaders to finally, really, get to work.”